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There is much emerging information surrounding the impact of sleep duration and quality on food choice and consumption in both children and adults. However, less attention has been paid to the effects of dietary patterns and specific foods on nighttime sleep. Early studies have shown that certain dietary patterns may affect not only daytime alertness but also nighttime sleep. In this review, we surveyed the literature to describe the role of food consumption on sleep. Research has focused on the effects of mixed meal patterns, such as high-carbohydrate plus low-fat or low-carbohydrate diets, over the short term on sleep. Such studies highlight a potential effect of macronutrient intakes on sleep variables, particularly alterations in slow wave sleep and rapid eye movement sleep with changes in carbohydrate and fat intakes. Other studies instead examined the intake of specific foods, consumed at a fixed time relative to sleep, on sleep architecture and quality. Those foods, specifically milk, fatty fish, tart cherry juice, and kiwifruit, are reviewed here. Studies provide some evidence for a role of certain dietary patterns and foods in the promotion of high-quality sleep, but more studies are necessary to confirm those preliminary findings., Competing Interests: 2 Author disclosures: M-P St-Onge, A Mikic, and CE Pietrolungo, no conflicts of interest., (© 2016 American Society for Nutrition.)

Objective: The role of metabolic condition and diet in regulating circulating levels of adropin, a peptide hormone linked to cardiometabolic control, is not well understood. In this study, weight loss and diet effects on plasma adropin concentrations were examined., Methods: This report includes data from (1) a weight loss trial, (2) an evaluation of acute exercise effects on mixed-meal (60% kcal from carbohydrates) tolerance test responses, and (3) a meta-analysis to determine normal fasting adropin concentrations., Results: Distribution of plasma adropin concentrations exhibited positive skew and kurtosis. The effect of weight loss on plasma adropin concentrations was dependent on baseline plasma adropin concentrations, with an inverse association between baseline and a decline in concentrations after weight loss (Spearman's ρ = -0.575; P < 0.001). When ranked by baseline plasma adropin concentrations, only values in the upper quartile declined with weight loss. Plasma adropin concentrations under the main area of the bell curve correlated negatively with habitual carbohydrate intake and plasma lipids. There was a negative correlation between baseline values and a transient decline in plasma adropin during the mixed-meal tolerance test., Conclusions: Plasma adropin concentrations in humans are sensitive to dietary macronutrients, perhaps due to habitual consumption of carbohydrate-rich diets suppressing circulating levels. Very high adropin levels may indicate cardiometabolic conditions sensitive to weight loss., (© 2016 The Obesity Society.)

Purpose of Review: The adverse cardiovascular health effects of saturated fats have been debated recently since the publication of studies reporting no increase in cardiovascular risk with saturated fat intakes. We purport that this may be because of the varied nature of saturated fats, which range in length from 2 to over 20 carbon atoms, and review evidence surrounding the cardiovascular health effects of medium-chain triglycerides (MCT)., Recent Findings: MCTs are saturated fats of shorter chain length than other, more readily consumed saturated fats. Studies have reported that consumption of MCT may lead to improvements in body composition without adversely affecting cardio-metabolic risk factors. There may also be synergistic actions between MCT and n-3 polyunsaturated fats that may lead to improvements in cardiovascular health., Summary: It is clinically relevant to distinguish between sources of saturated fats for cardiovascular health. Medium, and possibly shorter chain, saturated fats behave differently than long-chain saturated fats and should not be judged similarly when it comes to their cardio-metabolic health effects. Given their neutral, and potentially beneficial cardiovascular health effects, they should not be categorized together.

Study Objectives: Sleep restriction alters food intake, but less is known about how dietary patterns affect sleep. Current goals were to determine whether: (1) sleep is different after consumption of a controlled diet vs. an ad libitum diet, and (2) dietary intake during ad libitum feeding is related to nocturnal sleep., Methods: Twenty-six normal weight adults (30-45 y), habitually sleeping 7-9 h/night, participated in a randomized-crossover inpatient study with 2 phases of 5 nights: short (4 h in bed) or habitual (9 h in bed) sleep. Only data from the habitual sleep phase were used for the present analyses. During the first 4 days, participants consumed a controlled diet; on day 5, food intake was self-selected. Linear regression was used to determine relations between daytime food intake and nighttime sleep on day 5., Results: Sleep duration did not differ after 3 days of controlled feeding vs. a day of ad libitum intake. However, sleep after ad libitum eating had less slow wave sleep (SWS, P = 0.0430) and longer onset latency (P = 0.0085). Greater fiber intake predicted less stage 1 (P = 0.0198) and more SWS (P = 0.0286). Percent of energy from saturated fat predicted less SWS (P = 0.0422). Higher percent of energy from sugar and other carbohydrates not considered sugar or fiber was associated with arousals (P = 0.0320 and 0.0481, respectively)., Conclusions: Low fiber and high saturated fat and sugar intake is associated with lighter, less restorative sleep with more arousals. Diet could be useful in the management of sleep disorders but this needs to be tested., Clinical Trial Registration: http://www.clinicaltrials.gov, #NCT00935402., (© 2016 American Academy of Sleep Medicine.)

Adropin is a peptide hormone encoded by the Energy Homeostasis Associated (ENHO) gene whose physiological role in humans remains incompletely defined. Here we investigated the impact of dietary interventions that affect systemic glucose and lipid metabolism on plasma adropin concentrations in humans. Consumption of glucose or fructose as 25% of daily energy requirements (E) differentially affected plasma adropin concentrations (P < 0.005) irrespective of duration, sex or age. Glucose consumption reduced plasma adropin from 3.55 ± 0.26 to 3.28 ± 0.23 ng/ml (N = 42). Fructose consumption increased plasma adropin from 3.63 ± 0.29 to 3.93 ± 0.34 ng/ml (N = 45). Consumption of high fructose corn syrup (HFCS) as 25% E had no effect (3.43 ± 0.32 versus 3.39 ± 0.24 ng/ml, N = 26). Overall, the effect of glucose, HFCS and fructose on circulating adropin concentrations were similar to those observed on postprandial plasma triglyceride concentrations. Furthermore, increases in plasma adropin levels with fructose intake were most robust in individuals exhibiting hypertriglyceridemia. Individuals with low plasma adropin concentrations also exhibited rapid increases in plasma levels following consumption of breakfasts supplemented with lipids. These are the first results linking plasma adropin levels with dietary sugar intake in humans, with the impact of fructose consumption linked to systemic triglyceride metabolism. In addition, dietary fat intake may also increase circulating adropin concentrations.

Objective and Background: We and others have reported that experimentally induced short sleep does not affect resting metabolic rate and leads to increased laboratory-measured 24-h energy expenditure. Here, we aimed to determine if sleep timing and/or quality are related to physical activity (PA) levels., Methods: Measures of PA via waist actigraphy, sleep diary, and sleep quality questionnaires were collected over a 7-18-day period in 22 adults (mean age ± standard deviation (SD): 35.8 ± 4.6 years, and mean body mass index ± SD: 23.8 ± 1.1 kg/m(2)) who were on their habitual sleep-wake and activity schedules., Results: During the recording period, mean (±SD) bedtime and wake times were 00:17 ± 1:07 h (range: 22:02-02:07 h) and 08:20 ± 1:14 h (range: 06:30-10:11 h), respectively. After controlling for sleep duration, later bedtime, wake time, and midpoint of sleep were associated with less time spent in moderate-to-vigorous PA (p = 0.013, p = 0.005, and p = 0.007, respectively), and increased time in sedentary PA (p = 0.016, p = 0.013, and p = 0.013, respectively)., Conclusions: Current results suggest that even relatively small alterations in sleep timing may influence PA. However, causality cannot be inferred from this cross-sectional study. Clinical intervention studies should be conducted to assess the relationship between sleep timing and energy balance., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Study Objectives: To determine if weight loss and/ or changes in apnea-hypopnea index (AHI) improve sleep architecture in overweight/ obese adults with type 2 diabetes (T2D) and obstructive sleep apnea (OSA)., Methods: This was a randomized controlled trial including 264 overweight/ obese adults with T2D and OSA. Participants were randomized to an intensive lifestyle intervention (ILI) or a diabetes and support education (DSE) control group. Measures included anthropometry, AHI, and sleep at baseline and year-1, year-2, and year-4 follow-ups., Results: Changes in sleep duration (total sleep time [TST]), continuity [wake after sleep onset (WASO)], and architecture stage 1, stage 2, slow wave sleep, and REM sleep) from baseline to year 1, 2, and 4 did not differ between ILI and DSE. Repeated-measure mixed-model analyses including data from baseline through year-4 for all participants demonstrated a significant positive association between AHI and stage 1 sleep (p < 0.001), and a significant negative association between AHI and stage 2 (p = 0.01) and REM sleep (p < 0.001), whereas changes in body weight had no relation to any sleep stages or TST. WASO had a significant positive association with change in body weight (p = 0.009)., Conclusions: Compared to control, the ILI did not induce significant changes in sleep across the 4-year follow-up. In participants overall, reduced AHI in overweight/ obese adults with T2D and OSA was associated with decreased stage 1, and increased stage 2 and REM sleep. These sleep architecture changes are more strongly related to reductions in AHI than body weight, whereas WASO may be more influenced by weight than AHI., Clinical Trial Registration Number: NCT00194259., (© 2014 American Academy of Sleep Medicine.)

Short sleep duration is increasingly recognized as a risk factor for obesity. Sleep is now considered 1 of the 3 lifestyle behaviors, along with diet and exercise, which are closely associated with health. If sleep duration is a causal factor in the etiology of obesity, it must affect energy intake and/or energy expenditure to create a positive energy balance. The preponderance of evidence to date points to an effect of sleep restriction on energy intake that exceeds the added energy costs of maintaining longer wakefulness. Observational studies describe greater intakes of energy, fat, and possibly carbohydrates in short sleepers and this is corroborated by clinical interventions. These intervention studies further provide mechanistic explanations, via alterations in hormonal and neuronal controls of food intake, for an association between short sleep and obesity.

Background: Medium chain triglycerides (MCT) enhance thermogenesis and may reduce food intake relative to long chain triglycerides (LCT). The goal of this study was to establish the effects of MCT on appetite and food intake and determine whether differences were due to differences in hormone concentrations., Methods: Two randomized, crossover studies were conducted in which overweight men consumed 20 g of MCT or corn oil (LCT) at breakfast. Blood samples were obtained over 3 h. In Study 1 (n=10), an ad lib lunch was served after 3 h. In Study 2 (n=7), a preload containing 10 g of test oil was given at 3 h and lunch was served 1 h later. Linear mixed model analyses were performed to determine the effects of MCT and LCT oil on change in hormones and metabolites from fasting, adjusting for body weight. Correlations were computed between differences in hormones just before the test meals and differences in intakes after the two oils for Study 1 only., Results: Food intake at the lunch test meal after the MCT preload (Study 2) was (mean±s.e.m.) 532±389 kcal vs 804±486 kcal after LCT (P<0.05). MCT consumption resulted in a lower rise in triglycerides (P=0.014) and glucose (P=0.066) and a higher rise in peptide YY (PYY, P=0.017) and leptin (P=0.036) compared with LCT (combined data). Correlations between differences in hormone levels (glucagon-like peptide (GLP-1), PYY) and differences in food intake were in the opposite direction to expectations., Conclusions: MCT consumption reduced food intake acutely but this does not seem to be mediated by changes in GLP-1, PYY and insulin.

Background/objectives: The extent to which alterations in energy expenditure (EE) in response to sleep restriction contribute to the short sleep-obesity relationship is not clearly defined. Short sleep may induce changes in resting metabolic rate (RMR), thermic effect of food (TEF) and postprandial substrate oxidation., Subjects/methods: Ten females (age and body mass index: 22-43 years and 23.4-28 kg m(-2)) completed a randomized, crossover study assessing the effects of short (4 h per night) and habitual (8 h per night) sleep duration on fasting and postprandial RMR and respiratory quotient (RQ). Measurements were taken after three nights using whole-room indirect calorimetry. The TEF was assessed over a 6-h period following consumption of a high-fat liquid meal., Results: Short versus habitual sleep did not affect RMR (1.01±0.05 and 0.97±0.04 kcal min(-1); P=0.23). Fasting RQ was significantly lower after short versus habitual sleep (0.84±0.01 and 0.88±0.01; P=0.028). Postprandial EE (short: 1.13±0.04 and habitual: 1.10±0.04, P=0.09) and RQ (short: 0.88±0.01 and habitual: 0.88±0.01, P=0.50) after the high-fat meal were not different between conditions. TEF was similar between conditions (0.24±0.02 kcal min(-1) in both; P=0.98), as was the ~6-h incremental area under the curve (1.16±0.10 and 1.17±0.09 kcal min(-1) × 356 min after short and habitual sleep, respectively; P=0.92)., Conclusions: Current findings observed in non-obese healthy premenopausal women do not support the hypothesis that alterations in TEF and postprandial substrate oxidation are major contributors to the higher rate of obesity observed in short sleepers. In exploring a role of sleep duration on EE, research should focus on potential alterations in physical activity to explain the increased obesity risk in short sleepers.

Background: Breakfast is associated with lower body weight in observational studies. Public health authorities commonly recommend breakfast consumption to reduce obesity, but the effectiveness of adopting these recommendations for reducing body weight is unknown., Objective: We tested the relative effectiveness of a recommendation to eat or skip breakfast on weight loss in adults trying to lose weight in a free-living setting., Design: We conducted a multisite, 16-wk, 3-parallel-arm randomized controlled trial in otherwise healthy overweight and obese adults [body mass index (in kg/m²) between 25 and 40] aged 20-65 y. Our primary outcome was weight change. We compared weight change in a control group with weight loss in experimental groups told to eat breakfast or to skip breakfast [no breakfast (NB)]. Randomization was stratified by prerandomization breakfast eating habits. A total of 309 participants were randomly assigned., Results: A total of 283 of the 309 participants who were randomly assigned completed the intervention. Treatment assignment did not have a significant effect on weight loss, and there was no interaction between initial breakfast eating status and treatment. Among skippers, mean (±SD) baseline weight-, age-, sex-, site-, and race-adjusted weight changes were -0.71 ± 1.16, -0.76 ± 1.26, and -0.61 ± 1.18 kg for the control, breakfast, and NB groups, respectively. Among breakfast consumers, mean (±SD) baseline weight-, age-, sex-, site-, and race-adjusted weight changes were -0.53 ± 1.16, -0.59 ± 1.06, and -0.71 ± 1.17 kg for the control, breakfast, and NB groups, respectively. Self-reported compliance with the recommendation was 93.6% for the breakfast group and 92.4% for the NB group., Conclusions: A recommendation to eat or skip breakfast for weight loss was effective at changing self-reported breakfast eating habits, but contrary to widely espoused views this had no discernable effect on weight loss in free-living adults who were attempting to lose weight., (© 2014 American Society for Nutrition.)

Objective: This study investigated whether plasma adropin concentrations are influenced by sleep restriction and correlate with dietary preferences., Methods: Plasma adropin concentrations were measured by ELISA using samples from a study that investigated feeding behavior in sleep deprived lean (body mass index 22-26 kg/m(2) ) men and women aged 30-45 y. Sleep (habitual or restricted to 4h/night) and diet were controlled during a 4-day inpatient period. On day 5, food was self-selected (FS). Adropin was measured on day 4 in samples collected throughout the day, and then after an overnight fast at 0730 on days 5 (Pre-FS) and 6 (Post-FS)., Results: Plasma adropin concentrations were not affected by sleep restriction. However, circulating adropin concentrations correlated with food selection preferences in women, irrespective of sleep status. Pre-FS adropin correlated positively with fat intake (total fat, r = 0.867, P < 0.05; saturated fat, r = 0.959, P < 0.01) and negatively with carbohydrate intake (r = -0.894, P < 0.05) as a percent total energy. Post-FS adropin correlated with total (r = 0.797, P < 0.05) and saturated fat intake (r = 0.945, P < 0.01), and negative with total carbohydrate intake (r = -0.929, P < 0.01). Pre-FS adropin also correlated with fat intake in kcal adjusted for body size (total fat, r = 0.852, P < 0.05; saturated fat, r = 0.927, P < 0.01)., Conclusions: Plasma adropin concentrations correlate with fat consumption in women., (Copyright © 2013 The Obesity Society.)

Context: Sleep restriction alters responses to food. However, the underlying neural mechanisms for this effect are not well understood., Objective: The purpose of this study was to determine whether there is a neural system that is preferentially activated in response to unhealthy compared with healthy foods., Participants: Twenty-five normal-weight individuals, who normally slept 7-9 h per night, completed both phases of this randomized controlled study., Intervention: Each participant was tested after a period of five nights of either 4 or 9 h in bed. Functional magnetic resonance imaging (fMRI) was performed in the fasted state, presenting healthy and unhealthy food stimuli and objects in a block design. Neuronal responses to unhealthy, relative to healthy food stimuli after each sleep period were assessed and compared., Results: After a period of restricted sleep, viewing unhealthy foods led to greater activation in the superior and middle temporal gyri, middle and superior frontal gyri, left inferior parietal lobule, orbitofrontal cortex, and right insula compared with healthy foods. These same stimuli presented after a period of habitual sleep did not produce marked activity patterns specific to unhealthy foods. Further, food intake during restricted sleep increased in association with a relative decrease in brain oxygenation level-dependent (BOLD) activity observed in the right insula., Conclusion: This inverse relationship between insula activity and food intake and enhanced activation in brain reward and food-sensitive centers in response to unhealthy foods provides a model of neuronal mechanisms relating short sleep duration to obesity.

Data from cross-sectional and longitudinal studies have illustrated a relationship between short sleep duration (SSD) and weight gain. Individuals with SSD are heavier and gain more weight over time than normal-duration sleepers. This sleep-obesity relationship may have consequences for obesity treatments, as it appears that short sleepers have reduced ability to lose weight. Laboratory-based clinical studies found that experimental sleep restriction affects energy expenditure and intake, possibly providing a mechanistic explanation for the weight gain observed in chronic short sleepers. Specifically, compared to normal sleep duration, sleep restriction increases food intake beyond the energetic costs of increased time spent awake. Reasons for this increased energy intake after sleep restriction are unclear but may include disrupted appetite-regulating hormones, altered brain mechanisms involved in the hedonic aspects of appetite, and/or changes in sleep quality and architecture. Obstructive sleep apnea (OSA) is a disorder at the intersection of sleep and obesity, and the characteristics of the disorder illustrate many of the effects of sleep disturbances on body weight and vice versa. Specifically, while obesity is among the main risk factors for OSA, the disorder itself and its associated disturbances in sleep quality and architecture seem to alter energy balance parameters and may induce further weight gain. Several intervention trials have shown that weight loss is associated with reduced OSA severity. Thus, weight loss may improve sleep, and these improvements may promote further weight loss. Future studies should establish whether increasing sleep duration/improving sleep quality can induce weight loss.

Background: Epidemiologic evidence has shown a link between short sleep and obesity. Clinical studies suggest a role of increased energy intake in this relation, whereas the contributions of energy expenditure (EE) and substrate utilization are less clearly defined., Objective: Our aim was to investigate the effects of sleep curtailment on 24-h EE and respiratory quotient (RQ) by using whole-room indirect calorimetry under fixed-meal conditions., Design: Ten females aged 22-43 y with a BMI (in kg/m²) of 23.4-27.5 completed a randomized, crossover study. Participants were studied under short- (4 h/night) and habitual- (8 h/night) sleep conditions for 3 d, with a 4-wk washout period between visits. Standardized weight-maintenance meals were served at 0800, 1200, and 1900 with a snack at 1600. Measures included EE and RQ during the sleep episode on day 2 and continuously over 23 h on day 3., Results: Short compared with habitual sleep resulted in significantly higher (± SEM) 24-h EE (1914.0 ± 62.4 compared with 1822.1 ± 43.8 kcal; P = 0.012). EE during the scheduled sleep episode (0100-0500 and 2300-0700 in short- and habitual-sleep conditions, respectively) and across the waking episode (0800-2300) were unaffected by sleep restriction. RQ was unaffected by sleep restriction., Conclusions: Short compared with habitual sleep is associated with an increased 24-h EE of ~92 kcal (~5%)--lower than the increased energy intake observed in prior sleep-curtailment studies. This finding supports the hypothesis that short sleep may predispose to weight gain as a result of an increase in energy intake that is beyond the modest energy costs associated with prolonged nocturnal wakefulness.

Short sleep has been associated with cardiovascular risk. The aim of this study was to determine the impact of short-term sleep restriction on lipid profiles and resting blood pressure factors in young, normal-weight individuals (14 men, 13 women). Participants were randomized to five nights of either habitual (9 h) or short (4 h) sleep in a cross-over design separated by a 3-week washout period. There was no sleep × day interaction on lipid profile and blood pressure. Short-term sleep restriction does not alter lipid profiles and resting blood pressure in healthy, normal-weight individuals. The association between short sleep and increased cardiovascular risk reported in the epidemiological literature may be the result of long-term sleep restriction and poor lifestyle choices., (© 2013 European Sleep Research Society.)

Acute and chronic caffeine intakes have no impact on hydration status (R.J. Maughan and J. Griffin, J. Hum. Nutr. Diet. 16(6): 411-420, 2003), although no research has been conducted to analyze the effects using dilution techniques on total-body water (TBW) and its compartments. Therefore, the aim of this study was to investigate the effects of a moderate dose of caffeine on TBW, extracellular water (ECW), and intracellular water (ICW) during a 4-day period in active males. Thirty men, nonsmokers and low caffeine users (<100 mg·day(-1)), aged 20-39 years, participated in this double-blind, randomized, crossover trial (ClinicalTrials.gov: No. NCT01477294). The study included 2 conditions (5 mg·kg(-1)·day(-1) of caffeine and placebo (malt-dextrin)) of 4 days each, with a 3-day washout period. TBW and ECW were assessed by deuterium oxide and sodium bromide dilution, respectively, whereas ICW was calculated as TBW minus ECW. Body composition was assessed by dual-energy X-ray absorptiometry. Physical activity (PA) was assessed by accelerometry and water intake was assessed by dietary records. Repeated-measures analysis of variance (ANOVA) was used to test main effects. No changes in TBW, ECW, or ICW and no interaction between the randomly assigned order of treatment and time were observed (p > 0.05). TBW, ECW, and ICW were unrelated to fat-free mass, water ingestion, and PA (p > 0.05). These findings indicate that a moderate caffeine dose, equivalent to approximately 5 espresso cups of coffee or 7 servings of tea, does not alter TBW and fluid distribution in healthy men, regardless of body composition, PA, or daily water ingestion.

Humans have an innate requirement for sleep that is intrinsically governed by circadian and endocrine systems. More recently, reduced sleep duration has gained significant attention for its possible contribution to metabolic dysfunction. Significant evidence suggests that reduced sleep duration may elevate the risk for impaired glucose functioning, insulin resistance and type 2 diabetes. However, to date, few studies have determined the implications of reduced sleep duration with regard to glucose control during pregnancy. With the high prevalence of overweight and obesity in women of reproductive age, the occurrence of gestational diabetes mellitus (GDM) is increasing. GDM results in elevated risk of maternal and fetal complications, as well as increased risk of type 2 diabetes postpartum. Infants born to women with GDM also carry a life-long risk of obesity and type 2 diabetes. The impact of reduced sleep on glucose management during pregnancy has not yet been fully assessed and a paucity of literature currently exits. Herein, we review the association between reduced sleep and impaired carbohydrate metabolism and propose how reduced sleep during pregnancy may result in further dysfunction of the carbohydrate axis. A particular focus will be given to sleep-disordered breathing, as well as GDM-complicated pregnancies. Putative mechanisms of action by which reduced sleep may adversely affect maternal and infant outcomes are also discussed. Finally, we will outline important research questions that need to be addressed.

Short sleep duration and obesity are common occurrence in today's society. An extensive literature from cross-sectional and longitudinal epidemiological studies shows a relationship between short sleep and prevalence of obesity and weight gain. However, causality cannot be inferred from such studies. Clinical intervention studies have examined whether reducing sleep in normal sleepers, typically sleeping 7-9 h/night, can affect energy intake, energy expenditure, and endocrine regulators of energy balance. The aim of this review is to evaluate studies that have assessed food intake, energy expenditure, and leptin and ghrelin levels after periods of restricted and normal sleep. Most studies support the notion that restricting sleep increases food intake, but the effects on energy expenditure are mixed. Differences in methodology and component of energy expenditure analyzed may account for the discrepancies. Studies examining the effects of sleep on leptin and ghrelin have provided conflicting results with increased, reduced, or unchanged leptin and ghrelin levels after restricted sleep compared to normal sleep. Energy balance of study participants and potential sex differences may account for the varied results. Studies should strive for constant energy balance and feeding schedules when assessing the role of sleep on hormonal profile. Although studies suggest that restricting sleep may lead to weight gain via increased food intake, research is needed to examine the impact on energy expenditure and endocrine controls. Also, studies have been of short duration, and there is little knowledge on the reverse question: does increasing sleep duration in short sleepers lead to negative energy balance?

Sleep reduction is associated with increased energy intake and weight gain, though few studies have explored the relationship between sleep architecture and energy balance measures in the context of experimental sleep restriction. Fourteen males and 13 females (body mass index: 22-26 kg/m(2)) participated in a crossover sleep curtailment study. Participants were studied under two sleep conditions: short (4 h/night; 0100-0500 h) and habitual (9 h/night; 2200-0700 h), for 5 nights each. Sleep was polysomnographically recorded nightly. Outcome measures included resting metabolic rate (RMR), feelings of appetite-satiety, and ad libitum food intake. Short sleep resulted in reductions in stage 2 sleep and rapid eye movement (REM) sleep duration (P < 0.001), as well as decreased percentage of stage 2 sleep and REM sleep and increased slow wave sleep (SWS) percentage (P < 0.05). Linear mixed model analysis demonstrated a positive association between stage 2 sleep duration and RMR (P = 0.051). Inverse associations were observed between REM sleep duration and hunger (P = 0.031) and between stage 2 sleep duration and appetite for sweet (P = 0.015) and salty (P = 0.046) foods. Stage 2 sleep percentage was inversely related to energy consumed (P = 0.024). Stage 2 sleep (P = 0.005), SWS (P = 0.008), and REM sleep (P = 0.048) percentages were inversely related to fat intake, and SWS (P = 0.040) and REM sleep (P = 0.050) were inversely related to carbohydrate intake. This study demonstrates that changes in sleep architecture are associated with markers of positive energy balance and indicate a means by which exposure to short sleep duration and/or an altered sleep architecture profile may lead to excess weight gain over time.

Study Objective: To determine the hormonal effects of reducing sleep duration under controlled feeding conditions., Design: Randomized, crossover study., Setting: Inpatient., Participants: Twenty-seven normal weight, 30- to 45-yr-old men and women habitually sleeping 7-9 hr/night., Intervention: PARTICIPANTS WERE STUDIED UNDER TWO SLEEP CONDITIONS: short (4 hr in bed) or habitual (9 hr in bed) sleep. A controlled diet was provided for each 4-day study period., Measurements and Results: Fasting blood samples were obtained daily and frequent blood samples were obtained throughout day 4. The main outcomes measures included glucose, insulin, leptin, ghrelin, adiponectin, total glucagon-like peptide 1 (GLP-1) and peptide YY(3-36) (PYY(3-36)) concentrations. Body weights were reduced by 2.2 ± 0.4 lb and 1.7 ± 0.4 lb during the habitual and short sleep phases, respectively (both P < 0.0001). There was no effect of sleep duration on glucose, insulin, and leptin profiles (all P > 0.05). Ghrelin and GLP-1 responses differed by sex. Short sleep increased fasting (P = 0.054) and morning (08:00-12:00) (P = 0.042) total ghrelin in men but not women. The reverse was observed for GLP-1: afternoon levels (12:30-19:00) were lower (P = 0.016) after short sleep compared with habitual sleep in women but not men., Conclusions: These data suggest that, in the context of negative energy balance, short sleep does not lead to a state of increased insulin resistance, but may predispose to overeating via separate mechanisms in men and women., Clinical Trial Information: Trial registration on http://www.clinicaltrials.gov. #NCT00935402.

Evidence suggests that ginger consumption has anti-inflammatory, anti-hypertensive, glucose-sensitizing, and stimulatory effects on the gastrointestinal tract. This study assessed the effects of a hot ginger beverage on energy expenditure, feelings of appetite and satiety and metabolic risk factors in overweight men. Ten men, age 39.1±3.3 y and body mass index (BMI) 27.2±0.3 kg/m(2), participated in this randomized crossover study. Resting state energy expenditure was measured using indirect calorimetry and for 6h after consumption of a breakfast meal with or without 2 g ginger powder dissolved in a hot water beverage. Subjective feelings of satiety were assessed hourly using visual analog scales (VAS) and blood samples were taken fasted and for 3 h after breakfast consumption. There was no significant effect of ginger on total resting energy expenditure (P=.43) or respiratory quotient (P=.41). There was a significant effect of ginger on thermic effect of food (ginger vs control=42.7±21.4 kcal/d, P=.049) but the area under the curve was not different (P=.43). VAS ratings showed lower hunger (P=.002), lower prospective food intake (P=.004) and greater fullness (P=.064) with ginger consumption versus control. There were no effects of ginger on glucose, insulin, lipids, or inflammatory markers. The results, showing enhanced thermogenesis and reduced feelings of hunger with ginger consumption, suggest a potential role of ginger in weight management. Additional studies are necessary to confirm these findings., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Context: Mouse studies suggest that adropin, a peptide hormone, is required for metabolic homeostasis and prevention of obesity-associated insulin resistance. Whether obesity and insulin resistance are associated with low plasma adropin levels in humans is not known., Objectives: Our objective was to investigate the hypothesis that obesity and indicators of insulin resistance are associated with low adropin levels and determine whether weight loss regulates adropin levels., Design and Participants: Plasma was obtained from 85 female [age 21-67 yr, body mass index (BMI) 19.4-71.5 kg/m2] and 45 male (age 18-70 yr, BMI 19.1-62.6 kg/m2) volunteers for other clinical studies. The impact of Roux-en-Y gastric bypass was investigated in 19 obese females (BMI 37-65 kg/m2) using samples collected at baseline and 1-12 months after surgery., Results: Adropin levels correlate negatively with BMI (r=-0.335, P<0.001) and age (r=-0.263, P=0.003). Age-adjusted adropin levels are higher in males [4.1 ng/ml; 95% confidence interval (CI)=3.6-4.6 ng/ml] than females (3.0 ng/ml; 95% CI=2.6-3.4 ng/ml) (P=0.001). In all subjects, lower age-adjusted adropin levels were observed in overweight (3.3 ng/ml; 95% CI=2.8-3.8 ng/ml, P=0.033) and obese (2.7 ng/ml; 95% CI=2.1-3.3 ng/ml, P=0.001) compared with healthy-weight subjects (4.1 ng/ml; 95% CI=3.6-4.5 ng/ml). This effect was gender specific (weight category×gender, P<0.001) and was observed in males only. Aging and diagnosis with two or more metabolic syndrome risk factors was associated with low adropin levels, irrespective of sex. Adropin concentrations increased after Roux-en-Y gastric bypass, peaking 3 months after surgery (P<0.01)., Conclusions: Although males exhibit higher adropin levels that are reduced by obesity, aging and markers of insulin resistance are associated with low plasma adropin irrespective of sex.

Background: Epidemiologic evidence shows an increase in obesity concurrent with a reduction in average sleep duration among Americans. Although clinical studies propose that restricted sleep affects hormones related to appetite, neuronal activity in response to food stimuli after restricted and habitual sleep has not been investigated., Objective: The objective of this study was to determine the effects of partial sleep restriction on neuronal activation in response to food stimuli., Design: Thirty healthy, normal-weight [BMI (in kg/m²): 22-26] men and women were recruited (26 completed) to participate in a 2-phase inpatient crossover study in which they spent either 4 h/night (restricted sleep) or 9 h/night (habitual sleep) in bed. Each phase lasted 6 d, and functional magnetic resonance imaging was performed in the fasted state on day 6., Results: Overall neuronal activity in response to food stimuli was greater after restricted sleep than after habitual sleep. In addition, a relative increase in brain activity in areas associated with reward, including the putamen, nucleus accumbens, thalamus, insula, and prefrontal cortex in response to food stimuli, was observed., Conclusion: The findings of this study link restricted sleep and susceptibility to food stimuli and are consistent with the notion that reduced sleep may lead to greater propensity to overeat.

Mannooligosaccharides (MOS), extracted from coffee, have been shown to promote a decrease in body fat when consumed as part of free-living, weight-maintaining diets. Our objective was to determine if MOS consumption (4 g/day), in conjunction with a weight-loss diet, would lead to greater reductions in adipose tissue compartments than placebo. We conducted a double-blind, placebo-controlled weight-loss study in which 60 overweight men and women consumed study beverages and received weekly group counseling for 12 weeks. Weight and blood pressure were measured weekly, and adipose tissue distribution was assessed at baseline and at end point using magnetic resonance imaging. A total of 54 subjects completed the study. Men consuming the MOS beverage had greater loss of body weight than men consuming the Placebo beverage (-6.0 ± 0.6% vs. -2.3 ± 0.5%, respectively, P < 0.05). Men consuming the MOS beverage also had reductions in total body volume (P < 0.0001), total (P < 0.0001), subcutaneous (P < 0.0001), and visceral (P < 0.05) adipose tissue that were greater than changes observed in those consuming the Placebo beverage. In women, changes in body weight and adipose tissue compartments were not different between groups. Adding coffee-derived MOS to a weight-loss diet enhanced both weight and adipose tissue losses in men, suggesting a potential functional use of MOS for weight management and improvement in adipose tissue distribution. More studies are needed to investigate the apparent gender difference in response to MOS consumption.

Background: Although dietary weight-loss counseling usually employs a 500 to 1,000 kcal/day energy deficit to induce weight loss of 0.5 to 1 kg/week, this rate of weight loss is rarely achieved in research settings. Biological factors, such as changes in metabolic rate, are partly responsible, but would only account for a small deviation from expected weight loss. There must be other factors, behavioral or related to study design and implementation, that affect the rate of weight loss observed., Objective: To examine factors that influence the rate of weight loss obtained in clinical studies., Design: Thirty-five weight-loss studies published between 1995 and 2009 were identified that used dietary counseling to induce weight loss in healthy subjects. Studies were included if they had a duration of at least 6 weeks, used a strategy to counsel subjects to reduce free-living energy intakes, and reported weight-loss data based on a completers analysis. Variables that were associated with the rate of weight loss among age, sex (percent female subjects), initial body weight, frequency of dietary counseling, placebo use, exercise level, study length, and prescribed energy deficit were examined using linear regression analysis., Results: Study length was negatively related to the rate of weight loss (P<0.0001), whereas subject age (P<0.002), subject age squared (P=0.0073), initial body weight (P=0.0003), frequency of dietary counseling (P=0.0197), and prescribed energy deficit (P<0.0001) were positively related to the rate of weight loss observed in clinical studies., Conclusions: These findings provide a tool for investigators and clinical dietitians to predict the rate of weight loss that can be expected within a population given the age, initial body weight, frequency of dietary counseling, and energy deficit prescription. These data from clinical studies suggest that the rate of weight loss is greater in older and heavier subjects and with higher contact frequency and caloric restriction., (Copyright © 2012 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.)

Background: Evidence suggests a relation between short sleep duration and obesity., Objective: We assessed energy balance during periods of short and habitual sleep in normal-weight men and women., Design: Fifteen men and 15 women aged 30-49 y with a body mass index (in kg/m(2)) of 22-26, who regularly slept 7-9 h/night, were recruited to participate in this crossover inpatient study. All participants were studied under short (4 h/night) and habitual (9 h/night) sleep conditions, in random order, for 5 nights each. Food intake was measured on day 5, and energy expenditure was measured with the doubly labeled water method over each period., Results: Participants consumed more energy on day 5 during short sleep (2813.6 ± 593.0 kcal) than during habitual sleep (2517.7 ± 593.0 kcal; P = 0.023). This effect was mostly due to increased consumption of fat (20.7 ± 37.4 g; P = 0.01), notably saturated fat (8.7 ± 20.4 g; P = 0.038), during short sleep. Resting metabolic rate (short sleep: 1455.4 ± 129.0 kcal/d; habitual sleep: 1486.5 ± 129.5 kcal/d; P = 0.136) and total energy expenditure (short sleep: 2589.2 ± 526.5 kcal/d; habitual sleep: 2611.1 ± 529.0 kcal/d; P = 0.832) did not differ significantly between sleep phases., Conclusions: Our data show that a reduction in sleep increases energy and fat intakes, which may explain the associations observed between sleep and obesity. If sustained, as observed, and not compensated by increased energy expenditure, the dietary intakes of individuals undergoing short sleep predispose to obesity. This trial is registered at clinicaltrials.gov as NCT00935402.

Clinical studies have shown that the consumption of coffee mannooligosaccharides (MOS) decreases body fat, suggesting that MOS consumption may be useful for weight management. This study was undertaken to determine whether consumption of coffee MOS improves body composition when consumed as part of a weight-maintaining diet. In this double-blind, randomized, placebo-controlled study, 54 men and women, age 19-65 y and with BMI of 27-33 kg/m(2), consumed study beverages twice daily, for 12 wk. Beverages were identical except for the presence (MOS group) or absence (placebo group) of MOS (4 g/d). Body composition was assessed at baseline and endpoint using magnetic resonance imaging (MRI). Body weight, blood pressure, and assessments of feelings of appetite and satiety were taken weekly. Fifty men and women completed both baseline and endpoint MRI scans. There was a significant beverage x time interaction on total body volume (P = 0.026), total adipose tissue (TAT) (P = 0.046), and total subcutaneous adipose tissue (P = 0.032) in men but not women. Men consuming the MOS beverage had a greater percent change in total body volume (P = 0.043) and tended to have greater percent changes in subcutaneous (P = 0.069) and TAT (P = 0.098) compared with the placebo group. Consumption of a MOS-containing beverage, as part of a free-living weight-maintaining diet, leads to reductions in total body volume, relative to placebo, in men. More research is needed to further investigate the mechanism by which MOS may act to improve body composition and to elucidate the influence of gender.

Data from National Health and Nutrition Examination Surveys (NHANES) 1999-2004 have recently shown the percent body fat of American adults. Average American men and women have ~28 and 40% body fat. When categorized by BMI and age, the data also show high percent body fat values, particularly in lower BMI categories. These data should make one reflect on the health status of Americans in all BMI categories and the use of these data for public health recommendations.

It has been well documented that as individuals age, body composition changes, even in the absence of changes in body weight. Studies have shown that fat mass increases and muscle mass decreases with age. However, it is unclear why such changes occur. Resting metabolic rate (RMR) and substrate oxidation rates have been examined with aging. It has been proposed that reductions in RMR and fat oxidation may lead to changes in body composition. Alternatively, changes in body composition with aging may lead to reductions in RMR. The purpose of this review is to provide an overview of the literature surrounding the impact of aging on RMR and substrate oxidation. Although long-term longitudinal studies are lacking, most cross-sectional studies or short-term longitudinal studies show a reduction in RMR with aging that cannot be explained by changes in body composition including loss in fat-free mass, where the latter includes atrophy or decreases in the mass of high metabolic rate organs. There is indirect evidence suggesting that the metabolic rate of individual organs is lower in older compared with younger individuals. With aging, we conclude that reductions in the mass of individual organs/tissues and in tissue-specific organ metabolic rate contribute to a reduction in RMR that in turn promotes changes in body composition favoring increased fat mass and reduced fat-free mass., (2010 Elsevier Inc. All rights reserved.)

Sleep duration has been inversely associated with body mass index (BMI). We examined the relationship between self-reported sleep duration and BMI, waist circumference, and percent body fat in Black and White individuals from the CARDIA study. Box-Tidwell regression models were adjusted for age and race (Model 1), additional lifestyle and demographic variables (Model 2), and physical activity (Model 3). There were significant interactions between sleep and gender for the main outcome variables. In men, there was a trend for an inverse relationship between reported sleep duration and BMI in Model 2 (beta = -0.20, P = .053) but not model 3 (beta = -0.139, P = .191). In women, inverse relationships were observed between sleep duration and BMI (beta = -0.294, P = .005) and waist circumference (beta = -0.442, P = .059), in Model 2. These associations became nonsignificant in model 3 (BMI: beta = -0.172, P = .084; waist circumference: beta = -0.161, P = .474). Our results are consistent with previous findings that sleep is associated with BMI and other body composition variables. However, the relationship between self-reported sleep duration and body composition may be stronger in women than in men.

Background: Dropouts and missing data are nearly-ubiquitous in obesity randomized controlled trails, threatening validity and generalizability of conclusions. Herein, we meta-analytically evaluate the extent of missing data, the frequency with which various analytic methods are employed to accommodate dropouts, and the performance of multiple statistical methods., Methodology/principal Findings: We searched PubMed and Cochrane databases (2000-2006) for articles published in English and manually searched bibliographic references. Articles of pharmaceutical randomized controlled trials with weight loss or weight gain prevention as major endpoints were included. Two authors independently reviewed each publication for inclusion. 121 articles met the inclusion criteria. Two authors independently extracted treatment, sample size, drop-out rates, study duration, and statistical method used to handle missing data from all articles and resolved disagreements by consensus. In the meta-analysis, drop-out rates were substantial with the survival (non-dropout) rates being approximated by an exponential decay curve (e(-lambdat)) where lambda was estimated to be .0088 (95% bootstrap confidence interval: .0076 to .0100) and t represents time in weeks. The estimated drop-out rate at 1 year was 37%. Most studies used last observation carried forward as the primary analytic method to handle missing data. We also obtained 12 raw obesity randomized controlled trial datasets for empirical analyses. Analyses of raw randomized controlled trial data suggested that both mixed models and multiple imputation performed well, but that multiple imputation may be more robust when missing data are extensive., Conclusion/significance: Our analysis offers an equation for predictions of dropout rates useful for future study planning. Our raw data analyses suggests that multiple imputation is better than other methods for handling missing data in obesity randomized controlled trials, followed closely by mixed models. We suggest these methods supplant last observation carried forward as the primary method of analysis.

Milk consumption has decreased in children over the past years. This may play a role in the prevalence of pediatric obesity, because clinical studies have found a beneficial effect of milk consumption for weight management. The objectives of this study were to test whether high-milk consumption leads to greater weight loss and improvements in metabolic risk factors than low milk consumption during a 16-wk healthy eating diet. Overweight children aged 8-10 y were randomized to either high (4 x 236 mL/d) or low (1 x 236 mL/d) milk consumption. Children were provided dietary counseling on healthy eating at baseline and at wk 1, 2, 4, 6, 8, and 12. Serum glucose, insulin, and lipids were measured in fasting children at baseline and wk 8 and 16. An oral glucose tolerance test and body composition assessment by magnetic resonance imaging were conducted at baseline and endpoint. Body weight changes during the 16-wk study not differ between the high-milk (1.3 +/- 0.3 kg) and low-milk (1.1 +/- 0.3 kg) groups. There was no beverage x week interaction on any of the body composition and metabolic variables studied (blood pressure, serum lipids, glucose, and insulin). There was a beverage x week interaction (P = 0.044) on insulin area under the curve showing a trend toward reduced insulin output with a glucose challenge after high-milk consumption (P = 0.062). These data suggest that in overweight children, high-milk consumption in conjunction with a healthy diet does not lead to greater weight loss but may ameliorate insulin action compared with low-milk consumption.

Baseline serum C-reactive protein (CRP) concentrations play a role in the lipid response to diet. This study was a randomized, cross-over, controlled feeding study with 3 phases of 25 d each aimed at determining whether baseline CRP concentrations modulate the serum lipid response to diets differing in fat type and quantity. Participants were adult men and women, age 19-65 y, with LDL-cholesterol concentrations of 3.37-4.66 mmol/L. All participants consumed 3 diets differing in the type of snack, either low or high in fat: low-fat (30.8% of energy), moderate in fat and saturated fat (37.9 and 11.4% of energy, respectively), or moderate in fat and polyunsaturated fat (36.3 and 9.7% of energy, respectively). Using baseline CRP as a continuous variable, CRP x diet interactions on change in serum lipoprotein&#95;a (P = 0.045) and HDL-cholesterol (P = 0.06) were observed. When we used previously established categories to define CRP concentrations (low, <1 mg/L; intermediate, 1-3 mg/L; or high, >3 mg/L), we found a CRP x diet interaction on change in triglyceride concentrations (P = 0.03) and trends for CRP x diet interaction on change in LDL (P = 0.06) and total cholesterol (P = 0.07). If replicated, these results suggest that considering baseline CRP concentrations when prescribing dietary interventions to lower lipid concentrations may be useful. Individuals with high baseline CRP concentrations may benefit from moderate-fat, high polyunsaturated fat diets, whereas those with low baseline CRP concentrations may obtain greater lipid-lowering benefits from low-fat diets.

Dietary survey data show that intake of sugar-sweetened beverages is negatively associated with intake of milk, but these findings have yet to be confirmed by laboratory feeding studies. The objectives of the present study were to analyze children's intake across two laboratory-based ad libitum lunches to (a) investigate the relationships between intake of sweetened beverages, milk, and calcium, and (b) explore relationships between beverage consumption and child age and weight status. Data were extracted from a cohort of 126 3- to 7-year-old twins from diverse ethnic backgrounds who participated in a cross-sectional study (conducted from November 1999 to September 2002) designed to determine the genetic and environmental contributions to eating and body weight. At two visits, children ate ad libitum from lunches that offered a variety of sugar-sweetened and calcium-rich beverages. Total beverage and nutrient intakes were computed from the test meals. Weight, height, and waist circumference were assessed on the final visit. Regression analyses tested the associations among intake of sweetened beverages, calcium, and milk (primary aim), and whether these variables were associated with child age and weight status (secondary aim). Sweetened beverage intake was negatively correlated with both milk (P<0.01) and calcium (P<0.01) intakes, and these relationships remained after controlling for age, sex, and ethnicity (P<0.01). Child age was negatively associated with milk intake (r=-0.22, P<0.01) but positively associated with intake of sweetened beverages (r=0.27, P<0.01). Results support the notion that sugar-sweetened beverages displace milk in a single meal, and this phenomenon may vary with child age. Due to the cross-sectional nature of this study, future investigations are needed to determine the long-term implications of this consumption pattern. The possibility that limiting sweetened beverages may help optimize dietary calcium during childhood is a topic that merits further research.

Objective: Medium chain triglyceride (MCT) consumption may have a beneficial impact on weight management, however, some studies point to a negative impact of MCT oil consumption on cardiovascular disease risk. This study examined the effects of MCT oil consumption, as part of a weight loss diet, on metabolic risk profile compared to olive oil., Design: Thirty-one men and women, age 19-50 y and body mass index 27-33 kg/m(2), completed this randomized, controlled, 16-week weight loss program. Oils were consumed at a level of approximately 12% of the subjects' prescribed energy intakes in the form of muffins and liquid oil., Results: After controlling for body weight, there was a significant effect of time on fasting serum glucose (P = 0.0177) and total cholesterol (P = 0.0386) concentrations, and on diastolic blood pressure (P = 0.0413), with reductions in these variables occurring over time; there was no time-by-diet interaction for any of the parameters studied. Two of the 3 subjects in the MCT oil group with evidence of the metabolic syndrome at baseline did not have metabolic syndrome at endpoint. In the olive oil group, 6 subjects had the metabolic syndrome at baseline; 2 subjects no longer had metabolic syndrome at endpoint, 1 person developed metabolic syndrome, and 4 subjects did not have any change in their metabolic syndrome status., Conclusions: Our results suggest that MCT oil can be incorporated into a weight loss program without fear of adversely affecting metabolic risk factors. Distinction should be made regarding chain length when it comes to discussing the effects of saturated fats on metabolic risk factors.

Recent studies have found that baseline inflammatory status affected the response of the lipid profile to diet intervention. The goal of this study was to determine whether baseline inflammatory status, as reflected in C-reactive protein, interleukin 6, and tumor necrosis factor alpha, affected the lipid and insulin response to a weight loss intervention. A second goal was to determine whether inflammatory markers were related to traditional metabolic risk factors, such as lipids and insulin, in our sample of 190 overweight (body mass index, 27-30 kg/m2) premenopausal women. Body composition, fat distribution, serum lipids, insulin sensitivity (Si), and markers of inflammation were assessed at baseline and after weight loss to body mass index<25 kg/m2. All measurements were taken after a 4-week period of weight maintenance. Mixed-model, repeated-measures analysis was used to determine whether the interaction of baseline inflammatory status and time was significant in determining the changes in metabolic risk factors (Si and lipids) with weight loss. Weight loss was associated with significant reductions in total cholesterol, low-density lipoprotein cholesterol, triglycerides, and insulin, and increases in high-density lipoprotein cholesterol and Si. Triglycerides were higher (P=.054) and Si lower (P=.057) with increasing C-reactive protein tertile. The interaction of baseline inflammatory status and time was not significant for any outcome variable of interest. These results do not support the hypothesis that baseline inflammatory status affects the lipid and insulin response to a weight loss intervention. However, in these young, healthy women, weight loss had a beneficial impact on both inflammatory status and risk factors for chronic metabolic disease.

Objective: We have recently reported that parous European-American (EA) women have disproportionately more intra-abdominal adipose tissue (IAAT) than their nulliparous counterparts. Mediating mechanisms for IAAT accumulation remain unknown; however, some evidence suggests a possible catecholamine link. The objective of this study was to determine whether the IAAT-parity relationship found in EA women exists in African-American (AA) women and to determine whether catecholamines play a mediating role., Methods and Procedures: Subjects included 44 EA and 47 AA premenopausal women. Free-living physical activity by doubly labeled water (activity-related time equivalent (ARTE)), body composition (air plethysmography, computed tomography), and 24-h fractionated urinary catecholamines were measured., Results: Repeated measures ANOVA revealed parous EA and AA women had significantly higher IAAT than their nulliparous counterparts (100.1 +/- 28.5 and 76.2 +/- 34.8 cm(2) vs. 75.9 +/- 29.1 and 59.6 +/- 15.0 cm(2)). In AA women and nulliparous women, 24-h urinary dopamine was significantly higher (AA parous 260.8 +/- 88; EA parous 197.2 +/- 78.8; AA nulliparous 376.5 +/- 81; EA nulliparous 289.6 +/- 62). Multiple regression analysis for modeling IAAT indicated that race, parity, dopamine, ARTE, and VO(2max) were all significant and independent contributors to the model (Unstandardized betas: race -32.6 +/- 7.4; parity (number of births) 10.0 +/- 3.4; 24-h urinary dopamine 0.08 +/- 0.04; ARTE (min/day) -0.09 +/- 0.04; VO(2max) (ml/kg/min) -2.8 +/- 1.0)., Discussion: Independent of the potential confounders: age, race, percent body fat, IAAT, 24-h fractionated urinary catecholamines, physical activity, and VO(2max), parous EA and AA women had more IAAT than their nulliparous counterparts. Of the catecholamines, dopamine was found to be significantly lower in parous women and higher in AA's. Dopamine, however, did not explain racial or parity differences in IAAT.

Background: Clinical studies have shown that consumption of medium-chain triacylglycerols (MCTs) leads to greater energy expenditure than does consumption of long-chain triacylglycerols. Such studies suggest that MCT consumption may be useful for weight management., Objective: We aimed to determine whether consumption of MCT oil improves body weight and fat loss compared with olive oil when consumed as part of a weight-loss program., Design: Forty-nine overweight men and women, aged 19-50 y, consumed either 18-24 g/d of MCT oil or olive oil as part of a weight-loss program for 16 wk. Subjects received weekly group weight-loss counseling. Body weight and waist circumference were measured weekly. Adipose tissue distribution was assessed at baseline and at the endpoint by use of dual-energy X-ray absorptiometry and computed tomography., Results: Thirty-one subjects completed the study (body mass index: 29.8 +/- 0.4, in kg/m(2)). MCT oil consumption resulted in lower endpoint body weight than did olive oil (-1.67 +/- 0.67 kg, unadjusted P = 0.013). There was a trend toward greater loss of fat mass (P = 0.071) and trunk fat mass (P = 0.10) with MCT consumption than with olive oil. Endpoint trunk fat mass, total fat mass, and intraabdominal adipose tissue were all lower with MCT consumption than with olive oil consumption (all unadjusted P values < 0.05)., Conclusions: Consumption of MCT oil as part of a weight-loss plan improves weight loss compared with olive oil and can thus be successfully included in a weight-loss diet. Small changes in the quality of fat intake can therefore be useful to enhance weight loss.

Previous studies have linked overweight to lower milk and calcium consumption and have proposed a role of milk consumption on energy expenditure (EE). The goal of this study was to compare EE and food intake after a meal of either mixed-nutrient or single-nutrient beverage and examine whether supplementation with that beverage for 1 week will impact EE. This was a randomized, controlled crossover study testing the effect of 2 beverages, milk or fruit-flavored beverage, before and after a supplementation period of 1 week on EE. Food intake at a meal after a snack intake of each beverage was assessed at the end of each measurement period. Ten children, aged 9 to 10 years, participated in all of the testing sessions in the study. There was a significant beverage by testing day interaction on daily EE and thermic effect of food (TEF), whereby EE was greater with milk consumption relative to the fruit-flavored beverage on day 8 (P = .0014) and with fruit-flavored beverage consumption on day 1 vs day 8 (P = .01). Similarly, the TEF was greater with milk compared with fruit-flavored beverage consumption on day 8 (P = .0007) and with fruit-flavored beverage consumption on day 1 relative to day 8 (P = .0097). The TEF declined more rapidly during 6 hours after a fruit-flavored beverage than a milk meal (P = .0018). Food intake did not differ after snack consumption of each beverage before and after milk and fruit-flavored beverage supplementation periods. Over the longer term, consumption of milk beverages may have more favorable effects on energy balance in children than consumption of fruit-flavored beverages.

Background: Fat deposition in muscle has been found to be related to metabolic risk., Objective: This study compared soleus intramyocellular lipid (IMCL) concentrations after consumption of weight-maintaining, controlled diets differing in total fat and fat type., Design: This study consisted of 3 phases of 25 d each in a crossover, controlled feeding design. The low-fat (LF) diet provided 30.8% and 5.2% of energy from fat and polyunsaturated fat (PUFA), respectively. Two higher-fat diets were tested: the high-fat (HF) diet provided 37.9% and 5.8% of energy from fat and PUFA, respectively, and the high-PUFA (HPUFA) diet provided 36.3% and 9.7% of energy from fat and PUFA, respectively. Twenty-four men and women [age range: 19-65 y; body mass index (in kg/m(2)): 20-35] whose LDL and glucose concentrations were between 130 and 180 mg/dL and <126 mg/dL, respectively, completed all study phases., Results: IMCL content was 1.88 times as high after the HF diet (P = 0.005) and 1.71 times as high after the HPUFA diet (P = 0.002) as after the LF diet. There was no significant correlation between percentage fat mass or waist circumference and IMCL content. With pooled data from all diets, there was no significant correlation between IMCL content and insulin or glucose concentration. There was no significant difference in IMCL content in subjects with or without the metabolic syndrome or in subjects with LDL particle pattern A or B., Conclusions: Our results suggest that IMCL content is not modulated by dietary fat type but by total fat intake and that reducing fat intake effectively lowers IMCL. However, the metabolic implications of having lower IMCL concentrations are not clear.

Background: The perception that all high-fat snacks are unhealthy may be wrong., Objective: We aimed to assess whether replacing low-fat and high-fat snacks with snacks rich in polyunsaturated fatty acids (PUFAs) and low in saturated and trans fatty acids would improve cardiovascular health., Design: Thirty-three adults participated in a randomized crossover trial of 3 controlled feeding phases of 25 d each in which a different type of snack was provided: low-fat (30.8% of energy from fat, 5.2% of energy from PUFAs), high-PUFA (36.3% of energy from fat, 9.7% of energy from PUFAs), or high-fat (37.9% of energy from fat, 5.8% of energy from PUFAs) snack., Results: Each diet reduced LDL- and total cholesterol concentrations, but reductions were greater with the low-fat and the high-PUFA diets than with the high-fat diet: LDL cholesterol (11.8% and 12.5% compared with 8.8%, respectively; P = 0.03 and 0.01), total cholesterol (10.5% and 10.7% compared with 7.9%, respectively; P = 0.03 and 0.02). The high-PUFA diet tended to reduce triacylglycerol concentrations (9.4%; P = 0.06), and this change was greater than that with the low-fat (P = 0.028) and high-fat (P = 0.0008) diets., Conclusions: These data show that snack type affects cardiovascular health. Consuming snack chips rich in PUFA and low in saturated or trans fatty acids instead of high-saturated fatty acid and trans fatty acid or low-fat snacks leads to improvements in lipid profiles concordant with reductions in cardiovascular disease risk.

The objective of this study was to determine whether a weight-loss diet high in soy-protein-rich foods leads to greater weight loss and reductions in waist circumference, fat mass, and cardiovascular disease risk factors than a control diet. Groups of overweight women (body mass index [calculated as kg/m(2)] of 28 to 33, aged 25 to 49 years) were counseled to decrease their caloric intake by 500 kcal/day for a period of 12 weeks; in addition, the soy-protein-rich group was counseled to consume 15 g soy protein/1,000 kcal daily. Soy-protein-rich foods were provided to subjects. Body weight, waist circumference, percent body fat, fat-free mass, lipids, glucose, and insulin were measured at repeated intervals. Forty-seven women completed the study. Both groups lost a similar amount of weight both when a completers only (-3.18%+/-0.63% vs -4.04%+/-0.95% for soy-protein-rich and control diets, respectively) and a last-observation-carried-forward analysis (-1.93%+/-0.50% vs -2.50%+/-0.67%, for soy-protein-rich and control diets, respectively) were performed. There was no difference between groups in change in percent fat mass (-5.31%+/-1.50% for soy-protein-rich diet vs -3.94%+/-1.68% for control diet), percent fat-free mass, and waist circumference. There was no dietary assignment-by-group interaction on lipid, glucose, and insulin concentrations when analyses were done on completers only or on all subjects using a last-observation-carried-forward approach. Percent change in any of the biochemical parameters studied over the 12-week period was not significantly different between groups. Our results do not lend support to the emerging notion that soy-protein-rich foods could be considered potential functional foods for weight management, in the quantities consumed in this study.

Purpose of Review: Several body composition changes are known to occur with aging. The purpose of this review is to evaluate recent literature examining body composition changes with aging and how these relate to changes in physical function and metabolic risk., Recent Findings: Cross-sectional and longitudinal studies have observed increases in fat mass and decreases in muscle mass or lean tissue mass in older adults, often in the absence of differences or changes in body weight. Cross-sectional studies have also reported increases in intramyocellular lipid and liver fat in older versus younger adults and related changes in body composition with changes in physical function and metabolic risk, but few longitudinal data are available. Furthermore, most longitudinal studies lack precise methods of assessing body fat distribution and muscle and organ quality, resulting in a lack of detailed and precise information on body composition changes with aging and their relationship to health., Summary: Research to date has outlined a need for more detailed body composition measurements of aging adults. Absence of change in a total body compartment may mask a change in subcompartments that may impact health. Furthermore, intervention studies to determine ways to maintain body composition are consistent with healthy living throughout the aging process.

Objective: To examine the impact of nonfat and low-fat phytosterol-enriched beverages on low-density lipoprotein (LDL) electrophoretic characteristics., Design: Double-blind, randomized, crossover, placebo-controlled dietary trial., Setting: Diets were prepared and consumed at the Mary Emily Clinical Nutrition Research Unit of McGill University. Analyses were performed at the Institute on Nutraceuticals and Functional Foods of Laval University., Subjects and Intervention: In total, 15 moderately hypercholesterolemic persons consumed each of three experimental diets that each comprised a different beverage: nonfat placebo (NF control), nonfat with phytosterols (NFPS) or low-fat with phytosterols (LFPS). Participants consumed three beverages daily at meal time for a total of 1.8 g of phytosterols per day. Nondenaturing 2-16% polyacrylamide gradient gel electrophoreses were used to characterize LDL size characteristics., Results: The NFPS and LFPS beverage induced no significant changes in several features of the LDL size phenotype compared to the control diet., Conclusion: The consumption of phytosterol-supplemented nonfat and low-fat beverages is not associated with clinically meaningful changes in the LDL particle size phenotype.

Although specialized cortical pathways that process specific sensory stimuli and/or execute cognitive functions have been identified, the neuro-specificity for food-related stimuli has not been clearly demonstrated. We employed functional magnetic resonance imaging (fMRI) to compare neural systems associated with the appreciation of foods and nonfoods. Healthy, normal weight, right-handed men and women (n = 12; age 29.8 +/- 1.8 y, BMI 21.8 +/- 0.8 kg/m(2)) were imaged by fMRI while fasting. Real food and nonfood items were presented to subjects both visually and tactilely, during scanning. Subjects were instructed to pay attention to the items. A randomized 2 x 2 block design consisted of 4 conditions: visual food, visual nonfood, tactile food, and tactile nonfood. Brain regions that were significantly activated to a greater extent during the presentation of foods compared with nonfood items included the anterior cingulate, superior temporal gyrus, parahippocampal gyrus, hippocampus, and the insula. These findings support the claim that the presence of food (either seen or felt) elicits a unique cortical response that is differentiated from nonfood items. This neural substrate specialized for processing of foods informs models of food-related behavior.