Search

Background: The effect of calorie restriction (CR) on cognitive function is not well understood, and the impact of the dietary patterns consumed during CR has not been investigated., Objectives: We analyzed the combined association of CR and dietary quality with spatial working memory (SWM) in healthy adults without obesity., Methods: The Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy (CALERIE) trial was a 2-y, multisite clinical trial. This trial was registered at clinicaltrials.gov as NCT00427193. Participants were randomized to a 25% reduction in EI (n = 143) or an ad libitum Control (n = 76). The Dietary Inflammatory Index (DII) and the Healthy Eating Index (HEI) captured dietary quality, with a lower DII and higher HEI score indicating a healthier diet. The Cambridge Neuropsychological Test Automated Battery battery was used to assess SWM. Longitudinal associations between each dietary pattern index and SWM for CR and Control were assessed by multivariable negative binomial models that included baseline, 12-mo, and 24-mo visits., Results: Participants were aged 38.1 ± 7.2 y with a BMI of 25.1 ± 1.7 kg/m 2 . A total of 70% of the participants were female. Baseline mean DII and HEI scores were -0.15 (range: -3.77, 4.21) and 59.1 (24.1, 91.0) and did not differ between groups. Improvements in DII and HEI were significantly different between CR and Control over 2 y (both P-interaction = 0.001). In longitudinal analyses, there was no association of either index with SWM. Furthermore, though within-group improvements in SWM were observed at 12 mo, there was no statistically significant difference between CR (SWM errors: 9.0; 95% CI: 1.9, 41.6) and Control (11.7; 95% CI: 2.6, 53.5; P > 0.99), holding DII constant. Comparable results were observed at 24 mo and for the HEI., Conclusions: Dietary quality during CR was not associated with measures of SWM over 2 y in healthy adults without obesity. These results suggest that, in healthy populations, dietary patterns and CR may have a limited impact on working memory. Further research is required to understand the concurrent effect of these nutritional strategies., (Copyright © 2023. Published by Elsevier Inc.)

Background: Development of methods to accurately measure dietary intake in free-living situations-restaurants or otherwise-is critically needed to understand overall dietary patterns., Objective: This study aimed to develop and test reliability and validity of digital images (DI) for measuring children's dietary intake in quick-service restaurants (QSRs), validating against weighed plate waste (PW) and bomb calorimetry (BC)., Design: In 2016, cross-sectional data were collected at two time points within a randomized controlled trial assessing children's leftovers in QSRs from parents of 4- to 12-year-old children., Participants/setting: Parents (n = 640; mean age = 35.9 y; 70.8% female) consented and agreed to provide their child's PW for digital imaging, across 11 QSRs in Massachusetts in areas with low socioeconomic status and ethnically diverse populations., Outcome Measures: Outcome measures were interrater reliability for DIs, correspondence between methods for energy consumed and left over, and correspondence between methods across varying quantities of PW., Analyses Performed: Intraclass correlations, percent agreement, Spearman correlations, Wilcoxon signed rank tests, and Bland-Altman plots were used., Results: Interrater reliability ratings for DIs had substantial intraclass correlations (ICC = 0.94) but not acceptable exact percent agreement (80.2%); DI and PW energy consumed were significantly correlated (r = 0.96, P < 0.001); DI slightly underestimated energy consumed compared with PW (Mdiff = -1.61 kcals, P < 0.001). Bland-Altman plots showed high DI-PW correspondence across various energy amounts and revealed few outliers. Energy left over by BC was highly correlated with DI (r = 0.87, P < 0.001) and PW (r = 0.90, P < 0.001); and mean differences were not significantly different from DI (Mdiff = 9.77 kcal, P = 0.06) or PW (Mdiff = -2.84 kcal, P = 0.20)., Conclusions: Correspondence was high between PW and DI assessments of energy consumed, and high with BC energy left over. Results demonstrate reliability and practical validity of digital images for assessing child meal consumption in QSR settings., (Copyright © 2023 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.)

Background: Physical activity may be a way to increase and maintain fat-free mass (FFM) in later life, similar to the prevention of fractures by increasing peak bone mass., Objectives: A study is presented of the association between FFM and physical activity in relation to age., Methods: In a cross-sectional study, FFM was analyzed in relation to physical activity in a large participant group as compiled in the International Atomic Energy Agency Doubly Labeled Water database. The database included 2000 participants, age 3-96 y, with measurements of total energy expenditure (TEE) and resting energy expenditure (REE) to allow calculation of physical activity level (PAL = TEE/REE), and calculation of FFM from isotope dilution., Results: PAL was a main determinant of body composition at all ages. Models with age, fat mass (FM), and PAL explained 76% and 85% of the variation in FFM in females and males < 18 y old, and 32% and 47% of the variation in FFM in females and males ≥ 18 y old, respectively. In participants < 18 y old, mean FM-adjusted FFM was 1.7 kg (95% CI: 0.1, 3.2 kg) and 3.4 kg (95% CI: 1.0, 5.6 kg) higher in a very active participant with PAL = 2.0 than in a sedentary participant with PAL = 1.5, for females and males, respectively. At age 18 y, height and FM-adjusted FFM was 3.6 kg (95% CI: 2.8, 4.4 kg) and 4.4 kg (95% CI: 3.2, 5.7 kg) higher, and at age 80 y 0.7 kg (95% CI: -0.2, 1.7 kg) and 1.0 kg (95% CI: -0.1, 2.1 kg) higher, in a participant with PAL = 2.0 than in a participant with PAL = 1.5, for females and males, respectively., Conclusions: If these associations are causal, they suggest physical activity is a major determinant of body composition as reflected in peak FFM, and that a physically active lifestyle can only partly protect against loss of FFM in aging adults., (© The Author(s) 2021. Published by Oxford University Press on behalf of the American Society for Nutrition.)

Background: Unrestrained eating behavior, as a potential proxy for diet frequency, timing, and caloric intake, has been questioned as a plausible risk factor for digestive system cancers, but epidemiological evidence remains sparse., Objectives: We investigated prospectively the associations between unrestrained eating behavior and digestive system cancer risk., Methods: Participants in the Nurses' Health Study who were free of cancer and reported dietary information in 1994 were followed for ≤18 y. Cox models were used to estimate HRs and 95% CIs for unrestrained eating (eating anything at any time, no concern with figure change, or both) and risk of digestive system cancers., Results: During follow-up, 2064 digestive system cancer cases were documented among 70,450 eligible participants in analyses of eating anything at any time, In total, 2081 digestive system cancer cases were documented among 72,468 eligible participants in analyses of no concern with figure change. In fully adjusted analyses, women with the behavior of eating anything at any time had a higher risk of overall digestive system cancer (HR: 1.22; 95% CI: 1.10, 1.35), overall gastrointestinal tract cancer ((HR: 1.33; 95% CI: 1.18, 1.50), buccal cavity and pharynx cancer (HR: 1.50; 95% CI: 1.02, 2.21), esophageal cancer (HR: 1.62; 95% CI: 1.01, 2.62), small intestine cancer (HR: 1.92; 95% CI: 1.02,3. 59), and colorectal cancer (HR: 1.20; 95% CI: 1.04, 1.38), and a non-statistically significant increased risk of stomach cancer (HR: 1.54; 95% CI: 0.96,2.48), compared with women without this behavior. No statistically significant association was observed for pancreatic cancer and liver and gallbladder cancer. The combined effect of eating anything at any time and having no concern with figure change was associated with a significantly increased risk of overall digestive system cancer (HR: 1.27; 95% CI: 1.10, 1.46), overall gastrointestinal tract cancer (HR: 1.45; 95% CI: 1.23, 1.71), and colorectal cancer (HR: 1.34; 95% CI: 1.11, 1.63), compared with women exhibiting the opposite., Conclusions: Unrestrained eating behavior was independently associated with increased risk of gastrointestinal tract cancers. The potential importance of unrestrained eating behavior modification in preventing gastrointestinal tract cancers should be noted., (© The Author(s) 2021. Published by Oxford University Press on behalf of the American Society for Nutrition.)

Background & Aims: Unrestrained eating behavior has been thought to be a proxy for diet frequency, timing, and caloric intake. We investigated the association of unrestrained eating with mortality risk in the Nurses' Health Study prospectively., Methods: During follow-up (1994-2016), 21,953 deaths were documented among 63,999 eligible participants in analyses of eating anything at any time, 22,120 deaths were documented among 65,839 participants in analyses of no concern with figure change. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox proportional hazards models., Results: Eating anything at any time was associated with an increased mortality from cancer (overall HR, 95%CI: 1.07, 1.00-1.13; driven by gastrointestinal tract cancer: 1.30, 1.10-1.54) and respiratory disease (1.16, 1.05-1.29), and decreased cardiovascular disease-specific mortality (0.92, 0.86-0.99), compared to those without this behavior; however, no association was observed between this behavior and all-cause mortality (1.02, 0.99-1.05). Women who reported having no concern with figure change experienced higher risk of mortality from all-cause (1.08, 1.05-1.11), cancer (1.08, 1.02-1.14), and respiratory disease (1.18, 1.08-1.30), compared to those not reporting this behavior. Their combined effect was associated with a higher all-cause (1.09, 1.04-1.14), cancer-specific (overall: 1.18, 1.09-1.28; gastrointestinal tract cancer: 1.36, 1.08-1.71; lung cancer: 1.09; 1.04-1.14), and respiratory disease-specific (1.30, 1.13-1.50) mortality, and was inversely associated with cardiovascular disease-specific mortality (0.88, 0.80-0.98), compared to those exhibiting the opposite., Conclusions: Unrestrained eating was associated with increased risk of all-cause, cancer-specific (particularly for gastrointestinal tract cancer and lung cancer), and respiratory disease-specific mortality, and decreased risk of cardiovascular disease-specific mortality., Competing Interests: Conflict of interest BMW declares research funding from Celgene and Eli Lilly and Company and consulting for BioLineRx, Celgene, G1 Therapeutics, and GRAIL, outside the submitted work. ATC declares research funding from Bayer and consulting for Bayer, Pfizer Inc. and Boehringer Ingelheim, outside the submitted work. JAM declares institutional research funding from Boston Biomedical and consulting for Ignyta, Taiho Pharmaceutical, and Cota, outside the submitted work. CSF declares consulting for Agios, Bain Capital, Bayer, Celgene, Dicerna Pharmaceuticals, Eli Lilly and Company, Entrinsic Health Solutions, Five Prime Therapeutics, Genentech, Gilead Sciences, KEW, Merck & Co., Merrimack Pharmaceuticals, Pfizer, Sanofi, Taiho Pharmaceutical, and Unum Therapeutics, outside the submitted work. He also serves as a Director for CytomX Therapeutics and owns unexercised stock options for CytomX Therapeutics and Entrinsic Health Solutions, outside the submitted work. KN declares institutional research funding from Revolution Medicines, Celgene, Genentech, Gilead Sciences, Pharmavite, Tarrex Biopharma, and Trovagene, and consulting/advisory board fees from Array Biopharma, Bayer, Eli Lilly, Genentech, Seattle Genetics, and Tarrex Biopharma, outside the submitted work. Other authors declare no potential conflicts of interest., (Copyright © 2021 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.)

Background: Lifestyle interventions are the first-line treatment for obesity, but participant weight loss is typically low., Objectives: We evaluated the efficacy of an alternative lifestyle intervention [Healthy Weight for Living (HWL)] compared with a modified Diabetes Prevention Program (m-DPP). HWL was based on a revised health behavior change model emphasizing hunger management and the development of healthy food preferences. m-DPP was a standard Diabetes Prevention Program implemented with counselor time matched to HWL. Participants were adult dependents of military personnel and had overweight or obesity., Methods: Participants were randomly assigned to HWL (n = 121) or m-DPP (n = 117), delivered primarily by group videoconference with additional midweek emails. The primary outcome was 12-mo weight change. Secondary outcomes included 6-mo changes in cardiometabolic risk factors and diet. Intention-to-treat (ITT) and complete case (CC) analyses were performed using linear mixed models., Results: Retention did not differ between groups (72% and 66% for HWL and m-DPP at 12 mo, respectively; P = 0.30). Mean ± SE adjusted 12-mo weight loss in the ITT cohort was 7.46 ± 0.85 kg for HWL and 7.32 ± 0.87 kg for m-DPP (P = 0.91); in the CC cohort, it was 7.83 ± 0.82 kg for HWL and 6.86 ± 0.88 kg for m-DPP (P = 0.43). Thirty-eight percent of HWL and 30% of m-DPP completers achieved ≥10% weight loss (P = 0.32). Improvements in systolic blood pressure, LDL cholesterol, triglycerides, fasting glucose, general health, sleep, and mood were similar across groups; improvements in diastolic blood pressure were greater in m-DPP. Adjusted group mean reductions in energy intake were not significantly different between groups, but HWL participants were more adherent to their dietary prescription for lower glycemic index and high fiber and protein (P = 0.05 to <0.001 for ITT)., Conclusions: HWL and m-DPP showed equivalent and clinically impactful mean weight loss with cardiometabolic benefits. These results identify an alternative approach for behavioral treatment of overweight and obesity.This trial was registered at clinicaltrials.gov as NCT02348853., (© The Author(s) 2021. Published by Oxford University Press on behalf of the American Society for Nutrition.)

The amount of time spent in poor health at the end of life is increasing. This narrative review summarizes consistent evidence indicating that healthy dietary patterns and maintenance of a healthy weight in the years leading to old age are associated with broad prevention of all the archetypal diseases and impairments associated with aging including: noncommunicable diseases, sarcopenia, cognitive decline and dementia, osteoporosis, age-related macular degeneration, diabetic retinopathy, hearing loss, obstructive sleep apnea, urinary incontinence, and constipation. In addition, randomized clinical trials show that disease-specific nutrition interventions can attenuate progression-and in some cases effectively treat-many established aging-associated conditions. However, middle-aged and older adults are vulnerable to unhealthy dietary patterns, and typically consume diets with inadequate servings of healthy food groups and essential nutrients, along with an abundance of energy-dense but nutrient-weak foods that contribute to obesity. However, based on menu examples, diets that are nutrient-dense, plant-based, and with a moderately low glycemic load are better equipped to meet the nutritional needs of many older adults than current recommendations in US Dietary Guidelines. These summary findings indicate that healthy nutrition is more important for healthy aging than generally recognized. Improved public health messaging about nutrition and aging, combined with routine screening and medical referrals for age-related conditions that can be treated with a nutrition prescription, should form core components of a national nutrition roadmap to reduce the epidemic of unhealthy aging., (© The Author(s) 2021. Published by Oxford University Press on behalf of the American Society for Nutrition.)

Background: Emerging research indicates that eating timing may influence dietary intake and metabolic health. However, studies to date have not examined the association of multiple measures of eating timing with both dietary intake and metabolic health in adults with overweight and obesity., Objective: To examine the association of multiple measures of eating timing with dietary intake (ie, dietary composition, diet quality, and eating frequency) and metabolic health (ie, body composition and cardiometabolic risk)., Design: This is a cross-sectional analysis of baseline data from a weight loss and maintenance intervention collected from May 2015 to January 2018., Participants/setting: Participants were women with overweight or obesity who were dependents of active duty and retired military personnel (N = 229; mean ± standard error, BMI = 34.7 ± 0.4 kg/m 2 , age = 40.9 ± 0.7 years). The study was conducted at military installations in Massachusetts, Connecticut, New York, Colorado, and Kentucky., Main Outcome Measures: Eating timing variables examined included daily eating interval (time between first and last eating occasion), time-restricted eating (≤11 hours daily eating interval), early energy eaters (eating ≥60% of energy during the first half of time awake), and bedtime eaters (eating within 2 hours of bedtime)., Statistical Analysis: The main analysis was limited to those reporting plausible energy intake (64% of total sample [n = 146]). Linear, quantile, or logistic regression models were used to determine the association of eating timing with measures of dietary intake and metabolic health., Results: In individuals reporting plausible energy intake, each additional 1 hour in daily eating interval was associated with 53 kcal higher energy intake, higher glycemic load, eating frequency, and waist circumference (P < 0.05 for all). Significant associations were observed for: time-restricted eating and a lower energy intake, glycemic load, and eating frequency; early energy eating and higher carbohydrate intake; bedtime eating and a higher energy intake, glycemic load, and eating frequency., Conclusions: These findings lend support for the mechanistic targeting of eating timing in behavioral interventions aimed at improving dietary intake and body composition., (Copyright © 2021 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.)

Objective: There is substantial variability in the effectiveness of group lifestyle interventions for weight loss. We examined associations between intervention weight loss counselors and participant weight loss and program engagement in a structured lifestyle intervention., Methods: Data were from 575 adults (87% female, 51 (12) years, baseline BMI: 32.4 (7.2) kg/m 2 ) in an 11-week structured group lifestyle program. Participants self-enrolled in groups led by 11 weight loss counselors based on meeting times. All weight loss counselors received the same training. Linear mixed models were used to evaluate counselor predictors of participant percent (%) weight loss and program engagement (weight reporting throughout 11 weeks)., Results: Of the 575 participants, 415 (72%) defined as complete reporters, i.e. reported weight weekly, lost a mean 7.3% weight (range: +3.1% to 16.2%). Participant weight loss differed between weight loss counselors (p = 0.003), and adjusted mean participant weight loss by weight loss counselor ranged from 6% to 9%. Weight loss was greater for weight loss counselors with a graduate degree in nutrition than weight loss counselors with another graduate degree (8.3% versus 6.4%, p = 0.05), but was not different between weight loss counselors with and without graduate degrees. Higher counselor BMI was associated with higher participant weight loss (p = 0.005)., Conclusions: These results demonstrate the potential for quantitatively important effects of weight loss counselor characteristics on participant success and engagement in structured lifestyle interventions, indicating a need for research in this area., (Copyright © 2020 Asia Oceania Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.)

Background: Quick-service restaurants (QSRs) serve one-third of US children on any given day, yet no methods can directly measure energy (kcal) consumed in QSRs. Weighed plate waste is one feasible option, but the accuracy is unknown., Objective: The objective of this study was to determine the accuracy of weighed plate waste for measuring children's energy consumption in QSRs., Methods: Children's plate waste (entrées and sides) was collected for a larger study assessing a community-wide health messaging campaign to inform parents' orders for children in QSRs; a subsample (n = 194) was used for validation. Gross energy left over estimated by weighed plate waste combined with restaurant-stated nutrition information was compared to gross energy determined by bomb calorimetry, the gold-standard energy assessment technique. Analyses were conducted at the meal level (all food items, combined) and stratified by the number of items per meal (1, 2, or 3). Pearson correlations and paired t tests analyzed agreement; Bland-Altman statistics examined differences between energy estimations for the total and stratified subsample., Results: Overall, significant agreement was observed between weighed plate waste and bomb calorimetry (r = 0.99, P < 0.001). On average, weighed plate waste underestimated energy content by <2 kcal compared with bomb calorimetry (mean percent difference ± SD of 0.3% ± 10.7%); 94% of estimations fell within the limits of agreement (-23.5 to 26.8 kcal), and 63% and 24% of estimations differed by <10 or <20 net kcal, respectively. Although stratification by item number showed slight variation, mean differences for all strata were <5 kcal (t test P > 0.80), suggesting the accuracy of weighed plate waste for measuring meals of various sizes., Conclusions: Weighed plate waste is an accurate and valid field technique for measuring children's energy consumption from food in QSRs. Future improvements to capturing beverages, self-serve condiments, and sharing behaviors may improve the overall feasibility and accuracy., (Copyright © American Society for Nutrition 2019.)

Background: US national survey data shows fast food accounted for 11% of daily caloric intake in 2007-2010., Objective: To provide a detailed assessment of changes over time in fast-food menu offerings over 30 years, including food variety (number of items as a proxy), portion size, energy, energy density, and selected micronutrients (sodium, calcium, and iron as percent daily value [%DV]), and to compare changes over time across menu categories (entrées, sides, and desserts)., Design: Fast-food entrées, sides, and dessert menu item data for 1986, 1991, and 2016 were compiled from primary and secondary sources for 10 popular fast-food restaurants., Statistical Analysis: Descriptive statistics were calculated. Linear mixed-effects analysis of variance was performed to examine changes over time by menu category., Results: From 1986 to 2016, the number of entrées, sides, and desserts for all restaurants combined increased by 226%. Portion sizes of entrées (13 g/decade) and desserts (24 g/decade), but not sides, increased significantly, and the energy (kilocalories) and sodium of items in all three menu categories increased significantly. Desserts showed the largest increase in energy (62 kcal/decade), and entrées had the largest increase in sodium (4.6% DV/decade). Calcium increased significantly in entrées (1.2%DV/decade) and to a greater extent in desserts (3.9% DV/decade), but not sides, and iron increased significantly only in desserts (1.4% DV/decade)., Conclusions: These results demonstrate broadly detrimental changes in fast-food restaurant offerings over a 30-year span including increasing variety, portion size, energy, and sodium content. Research is needed to identify effective strategies that may help consumers reduce energy intake from fast-food restaurants as part of measures to improve dietary-related health issues in the United States., (Copyright © 2019 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.)

Background: Emerging evidence suggests novel roles for bacterially derived vitamin K forms known as menaquinones in health and disease, which may be attributable in part to anti-inflammatory effects. However, the relevance of menaquinones produced by gut bacteria to vitamin K requirements and inflammation is undetermined. Objective: This study aimed to quantify fecal menaquinone concentrations and identify associations between fecal menaquinone concentrations and serum vitamin K concentrations, gut microbiota composition, and inflammation. Design: Fecal and serum menaquinone concentrations, fecal microbiota composition, and plasma and fecal cytokine concentrations were measured in 80 men and postmenopausal women (48 men, 32 women, age 40-65 y) enrolled in a randomized, parallel-arm, provided-food trial. After consuming a run-in diet for 2 wk, participants were randomly assigned to consume a whole grain-rich (WG) or a refined grain-based (RG) diet for 6 wk. Outcomes were measured at weeks 2 and 8. Results: The median total daily excretion of menaquinones in feces was 850 nmol/d but was highly variable (range: 64-5358 nmol/d). The total median (IQR) fecal concentrations of menaquinones decreased in the WG diet compared with the RG diet [-6.8 nmol/g (13.0 nmol/g) dry weight for WG compared with 1.8 nmol/g (12.3 nmol/g) dry weight for RG; P < 0.01)]. However, interindividual variability in fecal menaquinone concentrations partitioned individuals into 2 distinct groups based on interindividual differences in concentrations of different menaquinone forms rather than the diet group or the time point. The relative abundances of several gut bacteria taxa, Bacteroides and Prevotella in particular, differed between these groups, and 42% of identified genera were associated with ≥1 menaquinone form. Menaquinones were not detected in serum, and neither fecal concentrations of individual menaquinones nor the menaquinone group was associated with any marker of inflammation. Conclusion: Menaquinone concentrations in the human gut appear highly variable and are associated with gut microbiota composition. However, the health implications remain unclear. This trial was registered at clinicaltrials.gov as NCT01902394., (© 2017 American Society for Nutrition.)

Background: Calorie restriction (CR) retards aging and increases longevity in many animal models. However, it is unclear whether CR can be implemented in humans without adverse effects on body composition. Objective: We evaluated the effect of a 2-y CR regimen on body composition including the influence of sex and body mass index (BMI; in kg/m 2 ) among participants enrolled in CALERIE-2 (Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy), a multicenter, randomized controlled trial. Design: Participants were 218 nonobese (BMI: 21.9-28.0) adults aged 21-51 y who were randomly assigned to 25% CR (CR, n = 143) or ad libitum control (AL, n = 75) in a 2:1 ratio. Measures at baseline and 12 and 24 mo included body weight, waist circumference, fat mass (FM), fat-free mass (FFM), and appendicular mass by dual-energy X-ray absorptiometry; activity-related energy expenditure (AREE) by doubly labeled water; and dietary protein intake by self-report. Values are expressed as means ± SDs. Results: The CR group achieved 11.9% ± 0.7% CR over 2-y and had significant decreases in weight (-7.6 ± 0.3 compared with 0.4 ± 0.5 kg), waist circumference (-6.2 ± 0.4 compared with 0.9 ± 0.5 cm), FM (-5.4 ± 0.3 compared with 0.5 ± 0.4 kg), and FFM (-2.0 ± 0.2 compared with -0.0 ± 0.2 kg) at 24 mo relative to the AL group (all between-group P < 0.001). Moreover, FFM as a percentage of body weight at 24 mo was higher, and percentage of FM was lower in the CR group than in the AL. AREE, but not protein intake, predicted preservation of FFM during CR ( P < 0.01). Men in the CR group lost significantly more trunk fat ( P = 0.03) and FFM expressed as a percentage of weight loss ( P < 0.001) than women in the CR group. Conclusions: Two years of CR had broadly favorable effects on both whole-body and regional adiposity that could facilitate health span in humans. The decrements in FFM were commensurate with the reduced body mass; although men in the CR group lost more FFM than the women did, the percentage of FFM in the men in the CR group was higher than at baseline. CALERIE was registered at clinicaltrials.gov as NCT00427193., (© 2017 American Society for Nutrition.)

Background: The effect of whole grains on the regulation of energy balance remains controversial. Objective: We aimed to determine the effects of substituting whole grains for refined grains, independent of body weight changes, on energy-metabolism metrics and glycemic control. Design: The study was a randomized, controlled, parallel-arm controlled-feeding trial that was conducted in 81 men and postmenopausal women [49 men and 32 women; age range: 40-65 y; body mass index (in kg/m 2 ): <35.0]. After a 2-wk run-in period, participants were randomly assigned to consume 1 of 2 weight-maintenance diets for 6 wk. Diets differed in whole-grain and fiber contents [mean ± SDs: whole grain-rich diet: 207 ± 39 g whole grains plus 40 ± 5 g dietary fiber/d; refined grain-based diet: 0 g whole grains plus 21 ± 3 g dietary fiber/d] but were otherwise similar. Energy metabolism and body-composition metrics, appetite, markers of glycemic control, and gut microbiota were measured at 2 and 8 wk. Results: By design, body weight was maintained in both groups. Plasma alkylresorcinols, which are biomarkers of whole-grain intake, increased in the whole grain-rich diet group (WG) but not in the refined grain-based diet group (RG) ( P -diet-by-time interaction < 0.0001). Beta ± SE changes (ΔWG compared with ΔRG) in the resting metabolic rate (RMR) (43 ± 25 kcal/d; P = 0.04), stool weight (76 ± 12 g/d; P < 0.0001), and stool energy content (57 ± 17 kcal/d; P = 0.003), but not in stool energy density, were higher in the WG. When combined, the favorable energetic effects in the WG translated into a 92-kcal/d (95% CI: 28, 156-kcal/d) higher net daily energy loss compared with that of the RG ( P = 0.005). Prospective consumption ( P = 0.07) and glycemia after an oral-glucose-tolerance test ( P = 0.10) trended toward being lower in the WG than in the RG. When nonadherent participants were excluded, between-group differences in stool energy content and glucose tolerance increased, and between-group differences in the RMR and prospective consumption were not statistically significant. Conclusion: These findings suggest positive effects of whole grains on the RMR and stool energy excretion that favorably influence energy balance and may help explain epidemiologic associations between whole-grain consumption and reduced body weight and adiposity. This trial was registered at clinicaltrials.gov as NCT01902394., (© 2017 American Society for Nutrition.)

Background: Excess energy intake from meals consumed away from home is implicated as a major contributor to obesity, and ∼50% of US restaurants are individual or small-chain (non-chain) establishments that do not provide nutrition information., Objective: To measure the energy content of frequently ordered meals in non-chain restaurants in three US locations, and compare with the energy content of meals from large-chain restaurants, energy requirements, and food database information., Design: A multisite random-sampling protocol was used to measure the energy contents of the most frequently ordered meals from the most popular cuisines in non-chain restaurants, together with equivalent meals from large-chain restaurants., Setting: Meals were obtained from restaurants in San Francisco, CA; Boston, MA; and Little Rock, AR, between 2011 and 2014., Main Outcome Measures: Meal energy content determined by bomb calorimetry., Statistical Analysis Performed: Regional and cuisine differences were assessed using a mixed model with restaurant nested within region×cuisine as the random factor. Paired t tests were used to evaluate differences between non-chain and chain meals, human energy requirements, and food database values., Results: Meals from non-chain restaurants contained 1,205±465 kcal/meal, amounts that were not significantly different from equivalent meals from large-chain restaurants (+5.1%; P=0.41). There was a significant effect of cuisine on non-chain meal energy, and three of the four most popular cuisines (American, Italian, and Chinese) had the highest mean energy (1,495 kcal/meal). Ninety-two percent of meals exceeded typical energy requirements for a single eating occasion., Conclusions: Non-chain restaurants lacking nutrition information serve amounts of energy that are typically far in excess of human energy requirements for single eating occasions, and are equivalent to amounts served by the large-chain restaurants that have previously been criticized for providing excess energy. Restaurants in general, rather than specific categories of restaurant, expose patrons to excessive portions that induce overeating through established biological mechanisms., (Copyright © 2016 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.)

Background: Controversy remains over the most effective approaches to prevent childhood malnutrition., Objectives: We tested the feasibility and effectiveness of delivering ready-to-use supplementary foods (RUSFs) as a second daily meal in preschool children aged 3-5 y in Guinea-Bissau, and compared RUSFs with different levels of dairy protein., Methods: This study was a 3 mo cluster-randomized controlled pilot trial of 2 RUSFs differing in dairy protein in 533 boys and girls from 9 preschools. Children receiving RUSFs were compared with wait-listed controls, and all students received a daily school lunch. The RUSFs were delivered 5 d/wk for 3 mo and contained 478 kcal and 11.5 g protein per 92-g daily serving. Deliveries included a ready-to-use supplementary food with 15% of protein from dairy sources (RUSF-15%) or one with 33% of protein from dairy sources (RUSF-33%). Intention-to-treat (ITT) and per-protocol analyses (>50 d of RUSF consumption) were conducted. Changes in the weight-for-age z score (WAZ) and height-for-age z score were primary outcomes. Additional outcomes included changes in mid-upper arm circumference (MUAC), hemoglobin, and retinol binding protein., Results: Baseline anthropometry was not different between groups (WAZ, -0.48 ± 1.04) and increased significantly over time (P < 0.01) with no effects of the RUSFs in ITT analyses. However, children consuming RUSFs for >50 d had a significantly greater increase in WAZ relative to the increase in controls (+0.40 and +0.32 for RUSF-15% and RUSF-33%, respectively, compared with +0.24 in controls, P < 0.01 and P < 0.05, respectively). RUSF-33%, but not RUSF-15%, also eliminated a decrease in MUAC observed in controls (-0.01 cm in RUSF-33% compared with -0.34 cm in controls, P < 0.05). The only difference between RUSF-15% and RUSF-33% was a mean decrease in hemoglobin in children receiving RUSF-15% (-0.5 compared with -0.002 g/dL, P = 0.05)., Conclusions: Implementation of 2-meal preschool feeding programs is feasible in low-income countries, and there are measurable benefits relative to 1-meal programs in children attending preschool regularly. In addition, MUAC and hemoglobin measurements indicate that meals with 33% compared with 15% of protein from dairy may help prevent wasting and anemia., (© 2016 American Society for Nutrition.)

The role of dietary energy density (ED) in the regulation of energy intake (EI) is controversial. Methodologically, there is also debate about whether beverages should be included in dietary ED calculations. To address these issues, studies examining the effects of ED on EI or body weight in nonelderly adults were reviewed. Different approaches to calculating dietary ED do not appear to alter the direction of reported relations between ED and body weight. Evidence that lowering dietary ED reduces EI in short-term studies is convincing, but there are currently insufficient data to determine long-term effectiveness for weight loss. The review also identified key barriers to progress in understanding the role of ED in energy regulation, in particular the absence of a standard definition of ED, and the lack of data from multiple long-term clinical trials examining the effectiveness of low-ED diet recommendations for preventing both primary weight gain and weight regain in nonobese individuals. Long-term clinical trials designed to examine the impact of dietary ED on energy regulation, and including multiple ED calculation methods within the same study, are still needed to determine the importance of ED in the regulation of EI and body weight., (© 2014 American Society for Nutrition.)

The doubly labeled water (DLW) method is considered the reference method for the measurement of energy expenditure under free-living conditions. However, the reproducibility of the DLW method in longitudinal studies is not well documented. This study was designed to evaluate the longitudinal reproducibility of the DLW method using 2 protocols developed and implemented in a multicenter clinical trial-the Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy (CALERIE). To document the longitudinal reproducibility of the DLW method, 2 protocols, 1 based on repeated analysis of dose dilutions over the course of the clinical trial (dose-dilution protocol) and 1 based on repeated but blinded analysis of randomly selected DLW studies (test-retest protocol), were carried out. The dose-dilution protocol showed that the theoretical fractional turnover rates for (2)H and (18)O and the difference between the 2 fractional turnover rates were reproducible to within 1% and 5%, respectively, over 4.5 y. The Bland-Altman pair-wise comparisons of the results generated from 50 test-retest DLW studies showed that the fractional turnover rates and isotope dilution spaces for (2)H and (18)O, and total energy expenditure, were highly reproducible over 2.4 y. Our results show that the DLW method is reproducible in longitudinal studies and confirm the validity of this method to measure energy expenditure, define energy intake prescriptions, and monitor adherence and body composition changes over the period of 2.5-4.4 y. The 2 protocols can be adopted by other laboratories to document the longitudinal reproducibility of their measurements to ensure the long-term outcomes of interest are meaningful biologically. This trial was registered at clinicaltrials.gov as NCT00427193.

Background: The energy intake necessary to maintain weight and body composition is called the energy requirement for weight maintenance and can be determined by using the doubly labeled water (DLW) method., Objective: The objective was to determine the energy requirements of nonobese men and women in the Comprehensive Assessment of Long-Term Effects of Reducing Intake of Energy 2 study., Design: Energy requirements were determined for 217 healthy, weight-stable men and women [aged >21 to <50 y; 70% female, 77% white; body mass index (BMI; in kg/m(2)) 22 to <28; 52% overweight] over 28 d with 2 consecutive 14-d DLW assessments in addition to serial measures of body weight and fat-free mass and fat mass by dual-energy X-ray absorptiometry. Energy intake and physical activity were also estimated by self-report over ≥6 consecutive d in each DLW period., Results: Total daily energy expenditure (TDEE) was consistent between the 2 DLW studies (TDEE1: 2422 ± 404 kcal/d; TDEE2: 2465 ± 408 kcal/d; intraclass correlation coefficient = 0.90) with a mean TDEE of 2443 ± 397 kcal/d that was, on average, 20% (580 kcal/d) higher in men than in women (P < 0.0001). The regression equation relating mean TDEE to demographics and weight was as follows: TDEE (kcal/d) = 1279 + 18.3 (weight, kg) + 2.3 (age, y) - 338 (sex: 1 = female, 0 = male); R(2) = 0.57. When body composition was included, TDEE (kcal/d) = 454 + 38.7 (fat-free mass, kg) - 5.4 (fat mass, kg) + 4.7 (age in y) + 103 (sex: 1 = female, 0 = male); R(2) = 0.65. Individuals significantly underreported energy intake (350 kcal/d; 15%), and underreporting by overweight individuals (~400 kcal/d; 16%) was greater (P < 0.001) than that of normal-weight individuals (~270 kcal/d; 12%). Estimates of TDEE from a 7-d physical activity recall and measured resting metabolic rate also suggested that individuals significantly underreported physical activity (~400 kcal/d; 17%; P < 0.0001)., Conclusion: These new equations derived over 1 mo during weight stability can be used to estimate the free-living caloric requirements of nonobese adults. This trial was registered at clinicaltrials.gov as NCT00427193.

The United States population is aging rapidly, and understanding the potential impact and feasibility of lifestyle interventions on the aging process is of central importance for addressing future population health and health care costs. This symposium addressed the question of whether caloric restriction may be a feasible strategy to improve human health by reductions in rates of primary and secondary aging in humans, viewed from the perspective of existing data in animal models, and by using emerging data from the human Comprehensive Assessment of Long-Term Reduction in Energy Intake trial, which is a randomized trial of human caloric restriction in free-living men and women.

Background: Worksites are potentially effective locations for obesity control because they provide opportunities for group intervention and social support. Studies are needed to identify effective interventions in these settings., Objective: We examined the effects of a multicomponent lifestyle intervention on weight loss and prevention of regain in 4 worksites (2 intervention and 2 control sites)., Design: Overweight and obese employees (n = 133) enrolled in this pilot worksite-randomized controlled trial with a 0-6-mo weight-loss phase and a 6-12-mo structured weight-maintenance phase. The intervention combined recommendations to consume a reduced-energy, low-glycemic load, high-fiber diet with behavioral change education. Outcome measurements included changes in body weight and cardiometabolic risk factors., Results: The mean ± SEM weight loss was substantial in intervention participants, whereas control subjects gained weight (-8.0 ± 0.7 compared with +0.9 ± 0.5 kg, respectively; P < 0.001), and 89% of participants completed the weight-loss phase. Intervention effects were not significant at the 0.05 level but would have been at the 0.10 level (P = 0.08) in a mixed model in which the worksite nested within group was a random factor. There were also significant improvements in cardiometabolic risk factors in intervention compared with control subjects regarding fasting total cholesterol, glucose, systolic blood pressure, and diastolic blood pressure (P ≤ 0.02 for each). No significant weight regain was observed in participants who enrolled in the structured weight-maintenance program (0.5 ± 0.7 kg; P = 0.65), and overweight and obese employees in intervention worksites who were not enrolled in the weight-loss program lost weight compared with subjects in control worksites (-1.3 ± 0.5 compared with +0.7 ± 0.2 kg, respectively; P = 0.02)., Conclusion: Worksites can be effective for achieving clinically important reductions in body weight and improved cardiometabolic risk factors. This trial was registered at clinicaltrials.gov as NCT01470222.

The relative importance of eating frequency to weight control is poorly understood. This review examines the evidence to date on the role of eating frequency in weight control in free-living adults. The majority of cross-sectional studies in free-living adults show an inverse relationship between eating frequency and adiposity; however, this is likely an artifact produced by the underreporting of eating frequency concurrent with underreporting of energy intake. When implausible energy intake reporting (which is mostly underreporting) is taken into account, the association between eating frequency and adiposity becomes positive. In studies in which eating frequency is prescribed and food intake is mostly self-selected, there is either no effect or a minor positive effect of eating frequency on energy intake. Most of those studies have been short-term and lack the necessary dietary biomarkers to validate reported energy intakes and eating frequencies. In conclusion, there is some suggestion from cross-sectional studies in which energy intake underreporting is taken into account and from experimental studies to date that greater eating frequency may promote positive energy balance. However, experimental studies of longer-term duration that include objective dietary biomarkers are necessary before firm conclusions about the relative importance of eating frequency in weight control can be made.

Hepatitis C virus (HCV) RNA-dependent RNA polymerase (NS5B) is required for viral replication. Crystal structures of the NS5B apoprotein show that the finger and thumb domains interact to encircle the active site, and that inhibitors defined by P495 resistance that bind to the thumb-finger interface displace the Δ1 finger loop and disrupt this structure. Since crystal structures may not reveal all of the conformations of a protein in solution we have developed an alternative method, using limited trypsin protease digestion, to investigate the impact of inhibitors as well as substrates on the movement of the Δ1 loop. This assay can be used to study NS5B under conditions that support enzymatic activity. In the absence of inhibitors, no specific region of NS5B was hypersensitive to trypsin, and no specific intermediate cleavage products were formed. Binding of P495-site inhibitors to NS5B induced specific trypsin hypersensitivity at lysine residues 50 and 51. Previously characterized inhibitors and mutant polymerases were used to link this specific trypsin hypersensitivity to movement of the Δ1 loop. Trypsin hypersensitivity identical to the inhibitor pattern was also induced by the binding of the RNA template. The addition of primer to the NS5B-template complex eliminated the hypersensitivity. The data are consistent with displacement of the Δ1 finger loop from the thumb by the binding of template, and reversal by the addition of primer or NTP. Our results complement inhibitor-enzyme co-crystal studies, and the assay provides a rapid and sensitive method to study dynamic changes in HCV NS5B polymerase conformation under conditions that support functional activity., (Copyright © 2010 Elsevier B.V. All rights reserved.)

The accuracy of stated energy contents of reduced-energy restaurant foods and frozen meals purchased from supermarkets was evaluated. Measured energy values of 29 quick-serve and sit-down restaurant foods averaged 18% more than stated values, and measured energy values of 10 frozen meals purchased from supermarkets averaged 8% more than originally stated. These differences substantially exceeded laboratory measurement error but did not achieve statistical significance due to considerable variability in the degree of underreporting. Some individual restaurant items contained up to 200% of stated values and, in addition, free side dishes increased provided energy to an average of 245% of stated values for the entrees they accompanied. These findings suggest that stated energy contents of reduced-energy meals obtained from restaurants and supermarkets are not consistently accurate, and in this study averaged more than measured values, especially when free side dishes were taken into account. If widespread, this phenomenon could hamper efforts to self-monitor energy intake to control weight, and could also reduce the potential benefit of recent policy initiatives to disseminate information on food energy content at the point of purchase., (Copyright 2010 American Dietetic Association. Published by Elsevier Inc. All rights reserved.)

The relative influence of genetics and the environment on factors associated with cardiovascular disease (CVD) and metabolic syndrome (MetS) remains unclear. We performed model-fitting analyses to quantify genetic, common environmental, and unique environmental variance components of factors associated with CVD and MetS [waist circumference, blood pressure, fasting plasma glucose and insulin, homeostatic model assessment of insulin resistance (HOMA-IR), and fasting plasma lipids] in adult male and female monozygotic twins reared apart or together. We also investigated whether MetS components share common influences. Plasma cholesterol and triglyceride concentrations were highly heritable (56-77%, statistically significant). Waist circumference, plasma glucose and insulin, HOMA-IR, and blood pressure were moderately heritable (43-57%, statistically significant). Unique environmental factors contributed to the variance of all variables (20-38%, perforce statistically significant). Common environmental factors contributed 23, 30, and 42% (statistically significant) of the variance of waist circumference, systolic blood pressure, and plasma glucose, respectively. Two shared factors influenced MetS components; one influenced all components except HDL cholesterol, another influenced only lipid (triglyceride and HDL cholesterol) concentrations. These results suggest that genetic variance has a dominant influence on total variance of factors associated with CVD and MetS and support the proposal of one or more underlying pathologies of MetS.

The enzymatic activity of hepatitis C virus (HCV) RNA-dependent RNA polymerase NS5B is modulated by the molar ratio of NS5B enzyme and RNA template. Depending on the ratio, either template or enzyme can inhibit activity. Inhibition of NS5B activity by RNA template exhibited characteristics of substrate inhibition, suggesting the template binds to a secondary site on the enzyme forming an inactive complex. Template inhibition was modulated by primer. Increasing concentrations of primer restored NS5B activity and decreased the affinity of template for the secondary site. Conversely, increasing template concentration reduced the affinity of primer binding. The kinetic profiles suggest template inhibition results from the binding of template to a site that interferes with primer binding and the formation of productive replication complexes.

Background: There remains no consensus about the optimal dietary composition for sustained weight loss., Objective: The objective was to examine the effects of 2 dietary macronutrient patterns with different glycemic loads on adherence to a prescribed regimen of calorie restriction (CR), weight and fat loss, and related variables., Design: A randomized controlled trial (RCT) of diets with a high glycemic load (HG) or a low glycemic load (LG) at 30% CR was conducted in 34 healthy overweight adults with a mean (+/-SD) age of 35 +/- 6 y and body mass index (kg/m(2)) of 27.6 +/- 1.4. All food was provided for 6 mo in diets controlled for confounding variables, and subjects self-administered the plans for 6 additional months. Primary and secondary outcomes included energy intake measured by doubly labeled water, body weight and fatness, hunger, satiety, and resting metabolic rate., Results: All groups consumed significantly less energy during CR than at baseline (P < 0.01), but changes in energy intake, body weight, body fat, and resting metabolic rate did not differ significantly between groups. Both groups ate more energy than provided (eg, 21% and 28% CR at 3 mo and 16% and 17% CR at 6 mo with HG and LG, respectively). Percentage weight change at 12 mo was -8.04 +/- 4.1% in the HG group and -7.81 +/- 5.0% in the LG group. There was no effect of dietary composition on changes in hunger, satiety, or satisfaction with the amount and type of provided food during CR., Conclusions: These findings provide more detailed evidence to suggest that diets differing substantially in glycemic load induce comparable long-term weight loss.

Discovery and development of effective antiviral agents to combat hepatitis C virus (HCV) is the focus of intensive research both in academia and in pharmaceutical companies. One of the HCV nonstructural proteins, NS5B (an RNA-dependent RNA polymerase), represents an attractive target in light of the clinical success of human immunodeficiency virus reverse transcriptase inhibitors. To identify and evaluate NS5B inhibitors, we developed a homogeneous, solid-phase, high-throughput biochemical assay for detecting NS5B enzymatic activity. In this assay, a biotinylated oligo(dT(12)) primer was immobilized onto streptavidin-coated scintillation proximity assay (SPA) beads, and after addition of homopolymeric A template, NS5B enzyme, and radiolabeled uridine 5'-triphosphate, the primer-dependent RNA synthesis occurred on beads. Optimization of the on-bead reaction resulted in the use of significantly less RNA template and NS5B enzyme while producing a faster steady state reaction rate compared to the solution-phase or off-bead SPA. The newly developed solid-phase assay is functionally comparable to the solution-phase assay as similar potencies of HCV NS5B inhibitors tested were obtained with the two assays. Furthermore, the solid-phase assay offers the advantage of delaying initiation, mimicking a physical preincubation step required for evaluating time-dependent inhibitors.

Objective: To examine relative associations of dietary composition variables with body mass index (BMI; calculated as kg/m2) among young and middle-aged US adults. We hypothesized that in subjects with physiologically plausible reported energy intakes, fiber intake would be inversely associated with BMI, independent of other dietary composition and sociodemographic variables., Subjects and Design: Data from adults age 20 to 59 years in the Continuing Survey of Food Intakes by Individuals (CSFII) 1994-1996 were used. Exclusions were pregnancy or lactation, food insecurity, missing weight or height data, or having only one dietary recall. Based on our previously published methods, a physiologically plausible reported energy intake was calculated as being within +/-22% of predicted energy requirements for the mean of two 24-hour recalls., Results: Reporting plausibility ([reported energy intake/predicted energy requirements]x100) averaged 83% in the total sample (N=4,539) and increased to 96% in the plausible sample (n=1,932). Only approximately 5% of the plausible sample consumed the Adequate Intake for fiber. In plausibly reporting women, fiber, its interaction with percentage energy from fat, and energy density were independently associated with BMI. Only percentage energy from fat was associated with BMI in men reporting plausibly. Compared with the total sample, stronger relationships between diet and BMI were observed among the plausible reporters. In women, a low-fiber (< 1.5 g/MJ), high-fat (> or = 35% energy) diet was associated with the greatest increase in risk of overweight or obesity compared with a high-fiber, low-fat diet., Conclusions: Weight control advice for US women should place greater emphasis on consumption of fiber.

The relative contribution of circulating glucose to meal-to-meal variability in energy intake is not known. In 8 free-living young (median age 26.5 y) women with healthy body weight (median BMI 22.2 kg/m(2)), we measured glucose in the interstitial space by an automated monitoring procedure (continuous glucose monitoring system, CGMS) for up to 3 consecutive days (mean 706 glucose readings per subject). We examined the association between interstitial glucose (which lags blood glucose by approximately 10 min), self-reported hunger, satiety, desire for a meal, and nutrient intakes. Participants reported consuming a typical Western diet (59% carbohydrate, 27% fat, 14% protein). Median (interquartile range) interstitial glucose was 5.2 mmol/L (4.7-5.8). Using repeated-measures techniques in univariate analyses, desire for a meal (r = 0.45, P < 0.0001), hunger (r = 0.37, P = 0.0002), satiety (r = -0.40, P < 0.0001), low interstitial absolute mean glucose up to 25 min before eating (r = -0.23, P = 0.02), and a large decline in glucose between 40 and 5 min before eating (r = -0.17, P = 0.08) were all associated with meal energy intake. In multivariate regression analyses, desire for a meal (P < 0.0001) and hunger (P = 0.02) were the strongest independent contributors to meal energy intake, whereas absolute mean glucose measured in the period 15 to 0 min before eating was marginally significant (P = 0.08). In conclusion, absolute glucose level is a significant predictor of energy intake in nonobese women. However, desire for a meal and hunger are quantitatively more important, emphasizing the importance of both glucose signals and nonglucose (internal or environmental) factors in within-subject variability in energy intake. In addition, the CGMS may have utility in understanding the role of circulating glucose in energy regulation in free-living subjects under a wide range of different nutritional conditions.

To test the hypothesis that total energy expenditure (TEE) and resting energy expenditure (REE) are low in extremely obese individuals, factors that could contribute to maintenance of excess weight, a cross-sectional study was conducted in 30 weight stable, extremely obese women [BMI (mean +/- SEM) 48.9 +/- 1.7 kg/m(2)]. TEE was measured over 14 d using the doubly labeled water method, REE and the thermic effect of feeding (TEF) were measured using indirect calorimetry, and activity energy expenditure (AEE) was calculated as TEE - (REE + TEF). Body composition was determined using a 3-compartment model. Subjects were divided into tertiles of BMI (37.5-45.0; 45.1-52.0; and 52.1-77.0 kg/m(2)) for data analysis. TEE and REE increased with increasing BMI tertile: TEE, 12.80 +/- 0.5, 14.67 +/- 0.5, and 16.10 +/- 0.9 MJ/d (P < 0.01); REE, 7.87 +/- 0.2, 8.78 +/- 0.3, and 9.94 +/- 0.6 MJ/d (P < 0.001), and these values were 29-38% higher than published means of measured TEE in nonobese individuals. No significant differences were observed among BMI tertiles for AEE, TEF, or physical activity level (PAL = TEE/REE, overall mean 1.64 +/- 0.16). The Harris-Benedict and WHO equations provided the closest estimates of REE (within 3%), whereas the obese-specific equations of Ireton-Jones overpredicted (40%) and Bernstein underpredicted (21%) REE. Extremely obese individuals have high absolute values for TEE and REE, indicating that excess energy intake contributes to the maintenance of excess weight. Standard equations developed for nonobese populations provided the most accurate estimates of REE for the obese individuals studied here. REE was not accurately predicted by equations developed in obese populations.

To identify existing dietary patterns and examine associations between these patterns and plasma homocysteine and B vitamin concentrations in an urban Chinese population living in Beijing (n = 119), dietary information was collected with a food frequency questionnaire designed for this population. Plasma homocysteine and B vitamin concentrations were examined. Food group variables, expressed as percentages of total energy intake, were entered into cluster analysis to define three distinct dietary pattern groups. The prevalence of high homocysteine (>11 micromol/L for women and 12 micromol/L for men), was 31.9%; of low folate (<6.8 nmol/L), 36.2%; of low vitamin B-12 (<221 pmol/L), 36.9%; and of low vitamin B-6 (<30 nmol/L), 16.0%. The three dietary patterns derived were defined by relatively greater intake of 1) fruit and milk, 2) red meat and 3) refined cereals. More than 40% of subjects in the refined cereals group had high plasma homocysteine and low plasma folate concentrations, and 67% had low plasma vitamin B-12 concentrations. Those following the refined cereals pattern were 4 and 5.2 times more likely to have high homocysteine and low vitamin B-12 concentrations, respectively, relative to the fruit and milk dietary pattern group (P < 0.01), after adjustment for potential confounders. High intake of refined cereals was associated with low B vitamin and high homocysteine concentrations, whereas the pattern high in fruit and milk was associated with the lowest homocysteine. Dietary patterns appear to play an important role in the micronutrient and homocysteine status of these Chinese adults.

Little is known about the relative effects of fermentable fiber (FF) vs. nonfermentable fiber (NFF) on energy regulation in humans. We compared 27 +/- 0.6 g/d supplements of FF (pectin, beta-glucan) and NFF (methylcellulose) for their ability to decrease ad libitum energy intake (EI) and hunger, increase satiety and cause spontaneous body weight and fat losses. Men and women (n = 11) aged 23-46 y, BMI 20.0-34.4 kg/m2, consumed first NFF and then FF for 3 wk each, with a 4-wk washout period between phases. Daily satiety assessed with analog scales was higher with NFF than FF (60.7 +/- 1.0 vs. 57.7 +/- 0.8 mm, P = 0.01). However, there were no differences in reported EI (NFF < FF by 7%, P = 0.31, NFF < baseline by 9.5%, P = 0.11), body weight (NFF 0.13 kg, P = 0.73; FF 0.13 kg, P = 0.60) or fat percentage (NFF -0.3%, P = 0.56; FF -0.1%, P = 0.66) within either phase. In contrast to findings in animals, NFF was more, rather than less satiating than FF, and use of neither NFF nor FF preparations was associated with body weight or fat loss. These pilot results suggest no role for short-term use of FF and NFF supplements in promoting weight loss in humans consuming a diet ad libitum.

Background: Little is known about the determinants of individual variability in body weight and fat loss after gastric bypass surgery or about the effects of massive weight loss induced by this surgery on energy requirements., Objectives: The objectives were to determine changes in energy expenditure and body composition with weight loss induced by gastric bypass surgery and to identify presurgery predictors of weight loss., Design: Thirty extremely obese women and men with a mean (+/- SD) age of 39.0 +/- 9.6 y and a body mass index (BMI; in kg/m(2)) of 50.1 +/- 9.3 were tested longitudinally under weight-stable conditions before surgery and after weight loss and stabilization (14 +/- 2 mo). Total energy expenditure (TEE), resting energy expenditure (REE), body composition, and fasting leptin were measured., Results: Subjects lost 53.2 +/- 22.2 kg body weight and had significant decreases in REE (-2.4 +/- 1.0 MJ/d; P < 0.001) and TEE (-3.6 +/- 2.5 MJ/d; P < 0.001). Changes in REE were predicted by changes in fat-free mass and fat mass. The average physical activity level (TEE/REE) was 1.61 at both baseline and follow-up (P = 0.98). Weight loss was predicted by baseline fat mass and BMI but not by any energy expenditure variable or leptin. Measured REE at follow-up was not significantly different from predicted REE., Conclusions: TEE and REE decreased by 25% on average after massive weight loss induced by gastric bypass surgery. REE changes were predicted by loss of body tissue; thus, there was no significant long-term change in energy efficiency that would independently promote weight regain.

Background: The relative influence of diet and physical activity on body fatness remains uncertain., Objective: The objective of the study was to investigate associations of dietary variables and physical activity with body fatness in urban Chinese adults., Design: We conducted a cross-sectional study in 130 weight-stable men and women aged 35-49 y. Subjects were selected from upper and lower tertiles of dietary fat and physical activity on the basis of screening questionnaires. Dietary intake was assessed by weighed food intake, physical activity level (PAL) was calculated as the ratio of predicted total energy expenditure (TEE) to predicted resting energy expenditure, and body composition was measured with the use of (2)H(2)O. Reported energy intake and predicted TEE were validated against TEE determined with the use of (2)H(2)(18)O (n = 73)., Results: Body fatness was positively associated with dietary variety (ie, variety of ingredients) (partial r = 0.186, P = 0.039) and frequency of consuming restaurant foods (partial r = 0.237, P = 0.001) and negatively associated with PAL (partial r = -0.307, P = 0.001) in a multiple regression analysis that controlled for sex and confounders. The combined variance accounted for by dietary variety and restaurant food consumption (9.1%) was equivalent to that for PAL (9.4%). Neither dietary fat nor energy density predicted body fatness, but dietary energy density predicted within-subject day-to-day variation in reported energy intake (P < 0.001)., Conclusions: Dietary variety, frequency of restaurant food consumption, and PAL significantly predicted body fatness in urban Chinese adults, but dietary fat did not. These findings support previous studies in US adults and suggest that dietary variables other than fat have an important influence on adult body composition.

Background: The specific underlying causes of adult weight gain remain uncertain., Objective: The objective was to determine the association of 3 measures of eating behavior with weight gain and body mass index (BMI; in kg/m(2)) in adults., Design: Current dietary restraint, disinhibition, and hunger were assessed with the use of the Eating Inventory in 638 healthy, nonsmoking women aged 55-65 y. In addition, subjects reported their current weight and height, their weight for 6 age intervals, and changes in voluntary dietary energy restriction over the past 10 y. Current weight and height were validated in 10% of subjects., Results: Current disinhibition strongly predicted weight gain and current BMI (partial r = 0.27 and 0.34, respectively, both P < 0.001). Neither restraint nor hunger was a significant independent predictor of either variable, but the positive associations between disinhibition and both weight gain and BMI were attenuated by restraint (P = 0.016 and 0.010, respectively, after adjustment for confounding variables). In the subpopulation of women who reported a stable level of voluntary dietary energy restriction, disinhibition also strongly predicted weight gain and higher BMI, and restraint was negatively associated with weight gain (partial r = -0.17, P = 0.019)., Conclusions: Higher disinhibition is strongly associated with greater adult weight gain and higher current BMI, and dietary restraint may attenuate this association when disinhibition is high. These findings suggest that eating behavior has an important role in the prevention of adult-onset obesity and that further studies are warranted.

There is little information on the accuracy of simple body composition methods in non-Western populations. We determined the percentage of body fat (%BF) by isotope dilution [oxygen-18 (H(2)(18)O) and deuterium oxide ((2)H(2)O)] and anthropometry in 71 healthy, urban Chinese adults aged 35-49 y [body mass index (BMI) 18-35 kg/m(2)]. The accuracy of several prediction equations for assessment of %BF from skinfold measurements was evaluated against %BF determined by H(2)(18)O dilution. We also assessed the relationship between BMI and %BF, and the fat-free mass (FFM) hydration coefficient for our population. All skinfold equations yielded means within approximately 2%BF of H(2)(18)O-derived %BF. However, on the basis of residual plot analysis and the 95% confidence interval (CI) for the mean difference between methods, the equations of Durnin and Womersley (for assessment of body density from skinfolds) coupled with that of Brozek et al. (for assessment of %BF from body density) provided the most valid assessment for individuals. In addition, the FFM hydration coefficient averaged 0.734 +/- 0.002 (SEM), indicating that the usually assumed value of 0.732 is appropriate for this population. Finally, although BMI had high specificity (90%) for classifying individuals as having body fat within the normal range (<24%BF for men, and <35%BF for women), it had poor sensitivity (66%) for identifying individuals as having high body fat. We conclude that compared with H(2)(18)O dilution, skinfold thickness can provide an accurate and reliable assessment of body composition in healthy Chinese adults. Furthermore, using the equation of Brozek et al. may be preferable to using Siri's equation to predict %BF from body density in populations in which individuals have >30%BF.