Search

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 ([+ or -] SD) age of 35 [+ or -] 6 y and body mass index (kg/[m.sup.2]) of 27.6 [+ or -] 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 tat, and resting metabolic rate did not differ significantly between groups. Both groups are 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 [+ or -] 4.1% in the HG group and -7.81 [+ or -] 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. KEY WORDS Glycemic load, caloric restriction, body weight, metabolism

The article discusses the concept of calories and its impact to weight loss. Highlighted is the result of a research which reveals that the composition of food including protein content in food is almost as important as the amount of food being consumed by a person. Moreover, it is also noted that exercise has minimal effect in the weight loss and burning of calories in the body.

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 ([+ or -] SD) age of 39.0 [+ or -] 9.6 y and a body mass index (BMI; in kg/[m.sup.2]) of 50.1 [+ or -] 9.3 were tested longitudinally under weight-stable conditions before surgery and after weight loss and stabilization (14 [+ or -] 2 mo). Total energy expenditure (TEE), resting energy expenditure (REE), body composition, and fasting leptin were measured. Results: Subjects lost 53.2 [+ or -] 22.2 kg body weight and had significant decreases in REE (-2.4 [+ or -] 1.0 MJ/d; P < 0.001) and TEE (-3.6 [+ or -] 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. 2003;78:22-30. KEY WORDS Obesity, weight loss, energy expenditure, fat mass, fat-free mass, body water, gastric bypass surgery, energy requirements

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 [sup.2]H[sup.2]O. Reported energy intake and predicted TEE were validated against TEE determined with the use of [sup.2][H.sub.2][sup.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. KEY WORDS Physical activity level, dietary fat, energy density, dietary variety, restaurant food, body composition, doubly labeled water, China, adults

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.sup.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. Am J Clin Nutr 2002;75:476-83. KEY WORDS Dietary restraint, disinhibition, body weight, BMI, obesity, overweight, postmenopausal women, body mass index, women

The effects of aging on energy requirements and energy balance have been studied by several research groups using the doubly labeled water method. The weight of evidence from these investigations suggests that current recommended dietary allowances underestimate the usual energy needs of adults of all ages, including older adults. In addition, doubly labeled water studies have found a significant negative association between body fatness and energy expenditure for physical activity, and a significant positive association between energy expenditure for physical activity and fat-free mass. Further studies are needed to refine estimates of energy requirements for different population groups and to address the role of physical activity in the prevention and treatment of obesity. Am J Clin Nutr 1998;68(suppl):975S-9S.

There remains controversy over the effects of dietary fat content on voluntary energy intake. Additionally, the question of whether there is a genetic susceptibility to overeating high-fat diets has not been resolved. To address these issues, we designed two diets: a low-fat diet providing [approximately equals] 20% of energy as fat and a high-fat diet with [approximately equals] 40% of energy as fat. The diets were matched for energy density, fiber, and palatability. In a two-phase, 18-d intervention study, voluntary energy intakes and macronutrient oxidation rates during the fasting and fed states were determined in seven pairs of identical male twins. In contrast with results of previous intervention studies, in which low-fat and high-fat diets were not matched for energy density and other associated variables, we observed no significant difference in voluntary energy intake between the low-fat and high-fat phases, and mean daily intakes were similar (10.3 and 10.7 MJ/d, respectively). Postprandial rates of fat oxidation tended to reflect fat intakes in the two dietary phases, thus helping to explain the lack of a difference in mean energy intakes. There was also a significant twin-pair similarity in differences in energy intakes between dietary phases (P = 0.013). These results suggest that dietary fat content does not have a major influence on voluntary energy intake when dietary variables usually associated with fat are controlled for and that there may be a familial influence on the effects of dietary fat content on energy intake.

We examined whether older individuals have an impairment in their ability to oxidize dietary fat, a factor that could help to explain age-associated weight gain. The subjects were 16 healthy younger and older women. Fat oxidation was determined by indirect calorimetry before and after consumption of four different test meals consumed [is greater than or equal to] 5 d apart. The intervention meals contained 0, 1046, 2092, or 4184 kJ (simulating extended fasting, and consumption of a snack, a small meal, and a moderately large meal, respectively), with 35% of energy from fat. The duration of each measurement was the amount of time required for postprandial energy expenditure to return to the premeal fasting value. A total of 96 measurements were obtained, including duplicates for all meal sizes in the younger women (in the follicular and luteal phases of the menstrual cycle). Total postprandial fat oxidation increased in proportion to meal size in the younger subjects, but did not increase above that for the 2092-kJ meal in the older women. In addition, older subjects had significantly lower total fat oxidation after consumption of the 4184-kJ meal (781 compared with 1029 kJ/measurement, P [is less than] 0.02) and also significantly greater fat deposition (745 compared with 464 kJ/measurement, P [is less than] 0.02). These findings suggest that, relative to younger women, older women have a reduced ability to oxidize dietary fat when they consume large meals.

The accuracy and precision of four different food intake assessment methods were evaluated in young and older women by comparing reported energy intakes with doubly labeled water measurements total energy expenditure (TEE). A study lasting 8 d was conducted in 10 young women aged 25.2 [+ or -] 1.1 y ([chi bar] [+ or -] SEM) and in 10 older women aged 74.0 t 1.4 y. Free-living TEE was measured over 7 d and food consumption was determined from weighed food intake data (7 d), a 24-h food recall (in duplicate), and two different food-frequency questionnaires [Fred Hutchinson Cancer Research Center (FHCRC)/Block and Willett, both in duplicate]. In addition, body composition was determined by using hydrodensitometry, and strenuous physical activity and the extent of dietary restraint were determined by questionnaire. In young women, 24-h recall gave mean energy intakes that were closest to measures of TEE (-0.34 [+ or -] 3.71 MJ/d compared with TEE, P = 0. 178), and energy intakes by food-frequency questionnaires were the only intake data that correlated significantly with individual values for TEE (P < 0.05). In older women, food-frequency questionnaires gave mean energy intakes that were closest to measured TEE (+0.53 [+ or -] 2.95 MJ/d with the Willett questionnaire and - 1.19 [+ or -] 3.02 MJ/d with the FHCRC/Block questionnaire). No energy intake data from this group correlated significantly with values for TEE. The 7-d weighed dietary intakes were significantly lower than measured TEE in both young and older women (-2.0 MJ/d in young and older women combined, P < 0.001), and did not correlate significantly with values for TEE, although they did most closely mirror the mean difference in TEE between the young and older women (2.30 MJ/d for TEE and 2.11 MJ/d for 7-d weighed intake). These data suggest that none of the methods studied gave accurate estimates of the usual energy requirements of individual subjects. In addition, the results suggest that for some types of studies, simple methods for assessing group mean dietary intake may actually give more accurate information than weighed dietary intakes. Am J Clin Nutr 1996;63:491-9.

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.Healthy nutrition has a broad, underrecognized role in preventing aging-related diseases and conditions. Updated public health recommendations on nutrition are needed to support healthy aging.

There is little information on the effects of age on energy requirements in women. This issue was investigated in a cross-sectional study of 10 normal-weight young women aged 25.2 [+ or -] 1.1 y ([x, bar above] [+ or -] SEM) and 10 normal-weight older women aged 74.0 [+ or -] 1.4 y. In a 9-d study, measurements were made of free-living total energy expenditure (TEE) by using the doubly labeled water technique, body composition by using hydrodensitometry, and resting energy expenditure (REE) by using indirect calorimetry. Mean values for reported levels of strenuous activity were within the expected range in both groups (31 [+ or -] 13 min/d in the young group and 7 [+ or -] 2 min/d in the older group). Energy requirements expressed as the ratio of TEE to REE were 1.80 [+ or -] 0.10 and 1.62 [+ or -] 0.06 (P < 0.01) in the young and older group, respectively. When values for REE predicted from body weight (pREE) were used, as suggested in the current recommended dietary allowances (RDAs), the ratios of TEE to pREE in the two groups were 1.85 [+ or -] 0.10 and 1.54 [+ or -] 0.04 (P < 0.05). The RDAs significantly underpredicted the energy requirements of the young group (P < 0.05), but there was no significant underprediction in the older group. Although obtained in a relatively small number of subjects, these results provide no evidence to indicate that the current RDAs underestimate the energy requirements of older women, in contrast with previous observations of an underestimation of energy requirements by the RDAs in older men.

•Student dialog sessions held in Boston, MA, reveal new insight toward equitable obesity prevention.•Focus on weight stigma and eating disorders to reduce harm while promoting healthy weight.•Increase training and research on racism and discrimination as obesity determinants.•Improve communication of strengths and limitations of BMI for assessing population health.

Lifestyle changes, in particular reducing energy intake, are the cornerstone of current approaches to weight loss and prevention of type 2 diabetes. However, there is currently no consensus that one [...]

Effective, standardized, and easily accessible weight management programs are urgently needed for military beneficiaries. Videoconference interventions have the potential for widespread scaling, and can provide both real time interaction and flexibility in delivery times regardless of location, but there is little information on their effectiveness and acceptability.

A study was conducted with an aim to determine what factors constitute quality prosthesis and ascertain which factors affect prosthesis satisfaction. Sixty-four women received full funding for their prosthesis and 38 women who received their hospital's usual funding were recruited.

For several cardiometabolic risk factors, values considered within normal range are associated with an increased risk of cardiovascular morbidity and mortality. We aimed to investigate the short-term and long-term effects of calorie restriction with adequate nutrition on these risk factors in healthy, lean, or slightly overweight young and middle-aged individuals.

Purpose: Programs focused on employee well-being have gained momentum in recent years, but few have been rigorously evaluated. This study evaluates the effectiveness of an intervention designed to enhance vitality and purpose in life by assessing changes in employee quality of life (QoL) and health-related behaviors.Design: A worksite-based randomized controlled trial.Setting: Twelve eligible worksites (8 randomized to the intervention group [IG] and 4 to the wait-listed control group [CG]).Participants: Employees (n = 240) at the randomized worksites.Intervention: A 2.5-day group-based behavioral intervention.Measures: Rand Medical Outcomes Survey (MOS) 36-item Short-Form (SF-36) vitality and QoL measures, Ryff Purpose in Life Scale, Center for Epidemiologic Studies questionnaire for depression, MOS sleep, body weight, physical activity, diet quality, and blood measures for glucose and lipids (which were used to calculate a cardiometabolic risk score) obtained at baseline and 6 months.Analysis: General linear mixed models were used to compare least squares means or prevalence differences in outcomes between IG and CG participants.Results: As compared to CG, IG had a significantly higher mean 6-month change on the SF-36 vitality scale (P= .003) and scored in the highest categories for 5 of the remaining 7 SF-36 domains: general health (P= .014), mental health (P= .027), absence of role limitations due to physical problems (P= .026), and social functioning (P= .007). The IG also had greater improvements in purpose in life (P< .001) and sleep quality (index I, P= .024; index II, P= .021). No statistically significant changes were observed for weight, diet, physical activity, or cardiometabolic risk factors.Conclusion: An intensive 2.5-day intervention showed improvement in employee QoL and well-being over 6 months.

Background: Stunting increases the risk of obesity in developing countries, particularly in girls and women, but the underlying reason is not known. Objective: Our objective was to test the hypothesis that stunted children have lower energy expenditure than do nonstunted children, a factor that has predicted an increased risk of obesity in other high-risk populations. Design: A cross-sectional study was conducted in shantytown children from Silo Paulo, Brazil. Twenty-eight stunted children aged 8-11 y were compared with 30 nonstunted children with similar weight-for-height. Free-living total energy expenditure (TEE) was measured over 7 d by using the doubly labeled water method. In addition, resting energy expenditure (REE) was measured by indirect calorimetry and body composition was measured by dual-energy X-ray absorptiometry. Results: There were no significant associations between stunting and any measured energy expenditure parameter, including REE adjusted for weight ([bar]x [+ or -] SEM: 4575 [+ or -] 95 compared with 4742 [+ or -] 91 kJ/d, in stunted and nonstunted children, respectively) and TEE adjusted for weight (8424 [+ or -] 239 compared with 8009 [+ or -] 221 kJ/d, in stunted and nonstunted children, respectively). In multiple regression models that included fat-free mass and fat mass, girls had significantly lower TEE than did boys (P [is less than] 0.05) but not significantly lower REE (P = 0.17). Conclusions: There was no association between stunting and energy expenditure after differences between groups in body size and composition were accounted for. However, the girls had lower TEE than did boys, which may help to explain the particularly high risk of obesity in stunted adolescent girls and women in urban areas of developing countries. Am J Clin Nutr 2000;72:1025-31. KEY WORDS Energy requirements, children, stunting, developing countries, girls, obesity, shantytowns, Brazil

Background: Previous research suggested that nutritionally stunted children may have increased risk of obesity, but little is known about potential underlying mechanisms. Objective: We sought to test the hypothesis that stunted children have a low metabolic rate and impaired fat oxidation relative to nonstunted children. Design: The subjects were 58 prepubertal boys and girls aged 8-11 y from the shantytowns of Sao Paulo, Brazil. Twenty-eight were stunted (height-for-age z score [is less than] -1.5) and 30 had similar weight-for-height but normal height (height-for-age z score [is greater than] -1.5). Parents of children in the 2 groups had equivalent height and body mass index values. Fasting and postprandial energy expenditure, respiratory quotient (RQ), and substrate oxidation were measured with indirect calorimetry in a 3-d resident study in which all food was provided and body composition was measured with dual-energy X-ray absorptiometry. Results: Stunted children had normal resting energy expenditure relative to body composition compared with control children (4559 [+ or -] 90 and 4755 [+ or -] 86 kJ/d, respectively; P = 0.14) and had normal postprandial thermogenesis (2.4 [+ or -] 0.3% and 2.0 [+ or -] 0.3% of meal load, respectively; P = 0.42). However, fasting RQ was significantly higher in the stunted group (0.92 [+ or -] 0.009 compared with 0.89 + 0.007; P = 0.04) and consequently, fasting fat oxidation was significantly lower (25 [+ or -] 2% compared with 34 [+ or -] 2% of energy expenditure; P [is less than] 0.01). Conclusions: Childhood nutritional stunting is associated with impaired fat oxidation, a factor that predicted obesity in other at risk populations. This finding may help explain recent increases in body fatness and the prevalence of obesity among stunted adults and adolescents in developing countries. Am J Clin Nutr 2000;72:702-7. KEY WORDS Fat oxidation, obesity, stunting, energy expenditure, children, metabolic rate, respiratory quotient, malnutrition, undernutrition, Brazil

Background: Factors affecting the accuracy of reported energy intake (rEI) need to be identified. Objective: Our objective was to investigate the association of psychological measures of eating behavior with the accuracy of rEI assessed by 7-d weighed intakes, a 24-h recall, and a food-frequency questionnaire. Design: Subjects were 26 restrained eaters aged 60.3 [+ or -] 0.6 y ([bar]x [+ or -] SEM) and weighing 63.8 [+ or -] 1.7 kg and 34 unrestrained eaters aged 59.4 [+ or -] 0.6 y and weighing 64.0 kg. rEI was assessed by using 3 dietary assessment methods and total energy expenditure (TEE) was determined by using doubly labeled water. Calculated EI (cEI) was determined as TEE corrected for the estimated change in body energy. Subjects completed the Eating Inventory. Results: rEI values were significantly lower than TEE values for all 3 dietary assessment methods (P [is less than] 0.05); there was no significant relation between rEI and TEE by any method. There was no significant difference in 100 x rEI:TEE between restrained and unrestrained eaters by any of the dietary assessment methods. When combined data from the 3 methods were used, 100 x rEI:cEI was not significantly different from 100% in unrestrained eaters (99 [+ or -] 6.8%) but was lower in restrained eaters (89.1 [+ or -] 5.3%; P [is less than] 0.05). There was a positive relation between hunger and 100 x rEI:TEE (P [is less than] 0.05). Conclusions: Low hunger is associated with undereating relative to normal eating during measurement of dietary intake; high dietary restraint may be associated with a reduction in reporting of consumed foods. Dietary hunger and restraint assessed with use of the Eating Inventory may help to identify subjects likely to underreport dietary intake. Am J Clin Nutr 2000;71:739-45. KEY WORDS Energy intake, total energy expenditure, psychological measures, weighed diet record, 24-h dietary recall, food-frequency questionnaire, dietary assessment, postmenopausal women

As a growing number of fast food and chain restaurants display the calorie content of their dishes on websites and menus, a study suggests some of this information may be [...]

Background: There is no consensus over best approaches to reliably prevent malnutrition in rural communities in low-income countries.Objective: We compared the effectiveness of 2 lipid-based ready-to-use supplementary foods (RUSFs) differing in dairy protein content to improve the nutritional status of mothers and at-risk infants and young children in rural Guinea-Bissau.Methods: A 3-month cluster-randomized controlled pilot trial of 2 RUSFs was conducted with 692 mothers and 580 mildly or moderately malnourished infants (6-23 months) and children (24-59 months) from 13 villages. The RUSFs contained either 478 (mothers, children) or 239 kcal/d (infants) with 15% or 33% of protein from dairy and were distributed at community health centers 5 d/wk. Controls were wait-listed to receive RUSF. Primary outcomes were mid-upper arm circumference (MUAC) in mothers, and weight-for-age and height-for-age z-scores (WAZ and HAZ) in infants and children.Results: There was a significant effect of the RUSF-33% on MUAC in mothers (P= .03). The WAZ and HAZ increased substantially, by ≈1 z-score, in infants and children (P< .01) independent of group randomization. In children, but not infants, baseline WAZ and change in maternal MUAC were associated with change in WAZ (β = .07, P= .02).Conclusion: Ready-to-use supplementary foods with higher dairy protein content had a significant benefit in village mothers, supporting a comparable recent finding in preschool children. In addition, supplementation of children <2 years resulted in improved growth independent of family nutritional status, whereas success in older children was associated with change in maternal nutrition, suggesting the need for community-level education about preventing malnutrition in older, as well as younger, children.

Background: The nutrition status of primary schoolchildren in Africa has received relatively little attention in comparison to that of younger children. We surveyed primary school students in Guinea-Bissau, a nation that is among the poorest in the world.Objective: Anthropometry and prevalence of anemia and vitamin A deficiency were assessed in schoolchildren participating in International Partnership for Human Development’s school feeding program in 2 regions of Guinea-Bissau.Methods: A cross-sectional survey of 32 schools in the regions of Cacheu and Oio was conducted in November 2011. Variables included age, gender, weight, height, hemoglobin, and retinol-binding protein concentrations. Zscores for height for age (HAZ), body mass index for age (BAZ), and weight for age were calculated using World Health Organization reference data.Results: Anthropometric assessment of 4784 students revealed stunting (HAZ < -2) in 15.5%, thinness (BAZ < -2) in 13.2%, and anemia in 42.0%. Stunting, thinness, and anemia were significantly more common in males, in students from Oio, and in older students. Vitamin A deficiency, detected in 21.5% of the population, was the only assessment that did not demonstrate significant differences between genders or regions. About 61.1% of all children had 1 or more indicators of undernutrition.Conclusion: There are substantial rates of stunting, thinness, underweight, anemia, and vitamin A deficiency in primary schoolchildren in Guinea-Bissau, even among those participating in a school lunch program and particularly among males and older students. The results suggest the need for evaluating feeding programs and other methods to improve nutrition status in primary school students, especially in older students.

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.

IMPORTANCE: Calorie restriction (CR) increases longevity in many species and reduces risk factors for chronic diseases. In humans, CR may improve health span, yet concerns remain about potential negative effects of CR. OBJECTIVE: To test the effect of CR on mood, quality of life (QOL), sleep, and sexual function in healthy nonobese adults. DESIGN, SETTING, AND PARTICIPANTS: A multisite randomized clinical trial (Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy Phase 2 [CALERIE 2]) was conducted at 3 academic research institutions. Adult men and women (N = 220) with body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) of 22.0 to 28.0 were randomized to 2 years of 25% CR or an ad libitum (AL) control group in a 2:1 ratio favoring CR. Data were collected at baseline, 12 months, and 24 months and examined using intent-to-treat analysis. The study was conducted from January 22, 2007, to March 6, 2012. Data analysis was performed from July 18, 2012, to October 27, 2015. INTERVENTIONS: Two years of 25% CR or AL. MAIN OUTCOMES AND MEASURES: Self-report questionnaires were administered to measure mood (Beck Depression Inventory-II [BDI-II], score range 0-63, higher scores indicating worse mood, and Profile of Mood States [POMS], with a total mood disturbance score range of −32 to 200 and higher scores indicating higher levels of the constructs measured), QOL (Rand 36-Item Short Form, score range 0-100, higher scores reflecting better QOL, and Perceived Stress Scale, score range 0-40, higher scores indicating higher levels of stress), sleep (Pittsburgh Sleep Quality Index [PSQI], total score range 0-21, higher scores reflecting worse sleep quality), and sexual function (Derogatis Interview for Sexual Function–Self–report, total score range 24-188, higher scores indicating better sexual functioning). RESULTS: In all, 218 participants (152 women [69.7%]; mean [SD] age, 37.9 (7.2) years; mean [SD] BMI, 25.1 [1.6]) were included in the analyses. The CR and AL groups lost a mean (SE) of 7.6 (0.3) kg and 0.4 (0.5) kg, respectively, at month 24 (P &lt; .001). Compared with the AL group, the CR group had significantly improved mood (BDI-II: between-group difference [BGD], −0.76; 95% CI, −1.41 to −0.11; effect size [ES], −0.35), reduced tension (POMS: BGD, −0.79; 95% CI, −1.38 to −0.19; ES, −0.39), and improved general health (BGD, 6.45; 95% CI, 3.93 to 8.98; ES, 0.75) and sexual drive and relationship (BGD, 1.06; 95% CI, 0.11 to 2.01; ES, 0.35) at month 24 as well as improved sleep duration at month 12 (BGD, −0.26; 95% CI, −0.49 to −0.02; ES, −0.32) (all P &lt; .05). Greater percent weight loss in the CR group at month 24 was associated with increased vigor (Spearman correlation coefficient, ρ = −0.30) and less mood disturbance (ρ = 0.27) measured with the POMS, improved general health (ρ = −0.27) measured with the SF-36, and better sleep quality per the PSQI total score (ρ = 0.28) (all P &lt; .01). CONCLUSIONS AND RELEVANCE: In nonobese adults, CR had some positive effects and no negative effects on health-related QOL. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00427193

ABSTRACTDaclatasvir (DCV) is a first-in-class hepatitis C virus (HCV) nonstructural 5A replication complex inhibitor (NS5A RCI) that is clinically effective in interferon-free combinations with direct-acting antivirals (DAAs) targeting alternate HCV proteins. Recently, we reported NS5A RCI combinations that enhance HCV inhibitory potential in vitro, defining a new class of HCV inhibitors termed NS5A synergists (J. Sun, D. R. O’Boyle II, R. A. Fridell, D. R. Langley, C. Wang, S. Roberts, P. Nower, B. M. Johnson F. Moulin, M. J. Nophsker, Y. Wang, M. Liu, K. Rigat, Y. Tu, P. Hewawasam, J. Kadow, N. A. Meanwell, M. Cockett, J. A. Lemm, M. Kramer, M. Belema, and M. Gao, Nature 527:245–248, 2015, doi:10.1038/nature15711). To extend the characterization of NS5A synergists, we tested new combinations of DCV and NS5A synergists against genotype (gt) 1 to 6 replicons and gt 1a, 2a, and 3a viruses. The kinetics of inhibition in HCV-infected cells treated with DCV, an NS5A synergist (NS5A-Syn), or a combination of DCV and NS5A-Syn were distinctive. Similar to activity observed clinically, DCV caused a multilog drop in HCV, followed by rebound due to the emergence of resistance. DCV–NS5A-Syn combinations were highly efficient at clearing cells of viruses, in line with the trend seen in replicon studies. The retreatment of resistant viruses that emerged using DCV monotherapy with DCV–NS5A-Syn resulted in a multilog drop and rebound in HCV similar to the initial decline and rebound observed with DCV alone on wild-type (WT) virus. A triple combination of DCV, NS5A-Syn, and a DAA targeting the NS3 or NS5B protein cleared the cells of viruses that are highly resistant to DCV. Our data support the observation that the cooperative interaction of DCV and NS5A-Syn potentiates both the genotype coverage and resistance barrier of DCV, offering an additional DAA option for combination therapy and tools for explorations of NS5A function.

The article presents questions and answers related to health and nutrition, namely, the nutritional difference between oat bran and oat meal, and the potential health benefits of activated charcoal capsules.

In their recent article, Alfenas and Mattes (1) conclude that the glycemic index values of individual foods do not predict glycemic response to mixed meals, nor influence measures of hunger. [...]

Childhood cancer survivors are at an increased risk of obesity but causes for this elevated risk are uncertain. We evaluated total energy expenditure in childhood cancer survivors using the doubly labeled water method in a cross-sectional study of 17 survivors of pediatric leukemia or lymphoma (median age, 11.5 y). Mean total energy expenditure was 2073 kcald, which was nearly 500 kcald lower than estimated energy requirements with recommended levels of physical activity. This energy gap is likely to contribute to the risk of obesity in this population and future trials are needed to assess implications and potential treatment strategies.

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.

Adult civilian dependents of active duty military personnel (ADMP) may play a central role in influencing the home food environment and the risk of overweight and obesity in American Warfighters and military families. However, there is no information on whether this group would be receptive to weight control programs. We conducted a survey to determine the level of interest of adult civilian dependents of ADMP in participating in a group weight control program. Subjects were a convenience sample of 191 adult civilian dependents of ADMP (94% women, 6% men) based in Massachusetts and aged 33.8 ± 8.4 years, body mass index 25.5 ± 5.5 kg/m(2). Overall, there was a significant effect of body mass index on interest in program participation (p = 0.004). Eighty five percent of overweight participants and 100% of obese participants reported being Moderately Likely or Very Likely to participate in a provided weight control program. In overweight and obese survey respondents there was no significant effect of ADMP rank on interest in program participation (p = 0.34). These findings suggest that overweight and obese adult civilian dependents of ADMP may be very receptive targets for programs to control overweight and obesity in military families.

Background: Recent studies have questioned the accuracy of using the current recommended dietary allowances (RDAs) to predict usual energy requirements in adults. Objective: We developed equations to predict adult energy requirements from simple anthropometric and laboratory measures by using the doubly labeled water method to determine each subject's total energy expenditure (TEE), which is equal to usual energy requirements in weight-stable individuals. Design: This was a cross-sectional study conducted with 93 healthy, free-living adults [44 men and 49 women; body mass index range (in kg/[m.sup.2]): 18.4-31.8] aged 18-81 y. Body fat and fat-free mass were measured by underwater weighing, physical activity was estimated by using activity monitors, and resting energy expenditure was determined by indirect calorimetry. Information on anthropometric variables and reported strenuous activity was also collected. Results: Three regression equations were developed and verified for accuracy by using bootstrap analysis and doubly labeled water data published by other research groups. The first equation used information on only age, weight, height, and sex and had an SEE for prediction of TEE of 1.80 MJ/d. The second and third equations used different combinations of basic and laboratory data and had SEEs of 1.55 and 1.65 MJ/d, respectively. With use of the same analytic approaches, the RDAs for energy were shown to significantly underestimate usual energy needs by [approximately equals] 10%; the extent of underestimation was significantly greater for subjects with high TEEs than for subjects with low TEEs. Conclusion: Regression equations based on doubly labeled water measurements of TEE appear to be more accurate than the current RDAs for predicting energy requirements in healthy, nonobese adults living in affluent countries. Am J Clin Nutr 1999;69:920-6.

Background: Short-term experimental studies suggest that dietary variety may influence body fatness but no long-term human studies have been reported. Objective: The purpose of this study was to determine whether dietary variety within food groups influences energy intake and body fatness. Design: Seventy-one healthy men and women (aged 20-80 y), who provided accurate reports of dietary intake and completed a body-composition assessment, were studied. Results: Dietary variety was positively associated with energy intake within each of 10 food groups (r = 0.27-0.56, P [is less than] 0.05). In multiple regression analysis with age and sex controlled for, dietary variety of sweets, snacks, condiments, entrees, and carbohydrates (as a group) was positively associated with body fatness (partial r = 0.38, P = 0.001) whereas variety from vegetables was negatively associated (partial r = -0.31, P = 0.01) (R2 = 0.46, P [is less than] 0.0001). In separate models, both a variety ratio (variety of vegetables/variety of sweets, snacks, condiments, entrees, and carbohydrates) and percentage dietary fat were significant predictors of body fatness (controlled for age and sex, partial r = -0.39 and 0.31, respectively, P < 0.01). However, dietary fat was no longer significantly associated with body fatness when the variety ratio and dietary fat were included in the same model. Conclusions: Our data, coupled with those of previous short-term studies, suggest that a high variety of sweets, snacks, condiments, entrees, and carbohydrates coupled with a low variety of vegetables promotes long-term increases in energy intake and body fatness. These findings may help explain the rising prevalence of obesity. Am J Clin Nutr 1999;69:440-7. KEY WORDS Dietary variety, dietary fat, dietary composition, body composition, obesity, energy intake, adults, vegetables

IMPORTANCE National recommendations for the prevention and treatment of obesity emphasize reducing energy intake through self-monitoring food consumption. However, little information is available on the energy content of foods offered by nonchain restaurants, which account for approximately 50% of restaurant locations in the United States. OBJECTIVE To measure the energy content of foods from independent and small-chain restaurants that do not provide stated information on energy content. DESIGN We used bomb calorimetry to determine the dietary energy content of the 42 most frequently purchased meals from the 9 most common restaurant categories. Independent and small-chain restaurants were randomly selected, and 157 individual meals were analyzed. SETTING Area within 15 miles of downtown Boston. PARTICIPANTS A random sample of independent and small-chain restaurants. MAIN OUTCOMES AND MEASURES Dietary energy. RESULTS All meal categories provided excessive dietary energy. The mean energy content of individual meals was 1327 (95% CI, 1248-1406) kcal, equivalent to 66% of typical daily energy requirements. We found a significant effect of food category on meal energy (P ≤ .05), and 7.6% of meals provided more than 100% of typical daily energy requirements. Within-meal variability was large (average SD, 271 kcal), and we found no significant effect of restaurant establishment or size. In addition, meal energy content averaged 49% greater than those of popular meals from the largest national chain restaurants (P &lt; .001) and in subset analyses contained 19% more energy than national food database information for directly equivalent items (P &lt; .001). CONCLUSIONS AND RELEVANCE National chain restaurants have been criticized for offering meals with excess dietary energy. This study finds that independent and small-chain restaurants, which provide no nutrition information, also provide excessive dietary energy in amounts apparently greater than popular meals from chain restaurants or information in national food databases. A national requirement for accurate calorie labeling in all restaurants may discourage menus offering unhealthy portions and would allow consumers to make informed choices about ordering meals that promote weight gain and obesity.

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.

Objective: We present an updated method for identifying physiologically implausible dietary reports by comparing reported energy intake (rEI) with predicted energy requirements (pER), and we examine the impact of excluding these reports. Research Methods and Procedures: Adult data from the Continuing Survey of Food Intakes by Individuals 1994 to 1996 were used. pER was calculated from the dietary reference intake equations. Within‐subject variations and errors in rEI [coefficient of variation (CV) ∼ 23%] over 2 days (d), pER (CV ∼ 11%), and measured total energy expenditure (mTEE; doubly labeled water, CV ∼ 8.2%) were propagated, where ±1 SD = . Thus, a report was identified as implausible if rEI was not within 78% to 122% of pER. Multiple cut‐offs between ±1 and ±2 SD were tested. Results: %rEI/pER = 81% in the total sample (n= 6499) and progressively increased to 95% in the ±1 SD sample (n= 2685). The ±1 to 1.4 SD samples yielded rEI‐weight associations closest to the theoretical relationship (mTEE to weight). Weak or spurious diet—BMI associations were present in the total sample; ±1 to 1.4 SD samples showed the strongest set of associations and provided the maximum nwhile maintaining biological plausibility. Discussion: Our methodology can be applied to different data sets to evaluate the impact of implausible rEIs on health outcomes. Implausible rEIs reduce the overall validity of a sample, and not excluding them may lead to inappropriate conclusions about potential dietary causes of health outcomes such as obesity.

Objective: We examined relationships of eating patterns and reported energy intake (rEI) with BMI percentile in U.S. children. Research Methods and Procedures: Two 24‐hour dietary recalls from the Continuing Surveys of Food Intakes by Individuals 1994 to 1996 and 1998 (1005 boys, 990 girls) were averaged, and children were categorized into three age groups: 3 to 5 years (n= 1077), 6 to 11 years (n= 537), and 12 to 19 years (n= 381). Physiologically implausible reports due to reporting bias or abnormal intake (rEI outside ±18% to 23% of predicted energy requirements; pER) were identified. Results: rEI averaged 109 ± 34% and 100 ± 10% of pER in the total and plausible samples, respectively. EI was overreported more in younger children and underreported more in overweight older children. Children with plausible rEI (45.3% of sample) averaged 4.7 eating occasions/d, 589 kcal/meal, 223 kcal/snack, and 2038 kcal/d. rEI was not associated with BMI percentile in the total sample. In the plausible sample, rEI, meal portion size, and meal energy were positively associated with BMI percentile in boys 6 to 11 years and in children 12 to 19 years. No relationships were found in children 3 to 5 years and girls 6 to 11 years. Relationships were more consistent and stronger in the plausible compared with the total sample. Discussion: Excluding implausible dietary reports may be necessary for discerning dietary associations with BMI percentile. EI and meal, but not snack, patterns may play a quantitatively greater role in weight regulation as children age.

AbstractObjective:To review existing methods and illustrate the use of a new, simple method for identifying inaccurate reports of dietary energy intake (rEI).Design:Comparison of rEI with energy requirements estimated by using total energy expenditure predicted (pTEE) from age, weight, height and sex using a previously published equation. Propagation of error calculations was performed and cut-offs for excluding rEI at plus or minus two standard deviations (?2 SD) and ?1 SD for the agreement between rEI and pTEE were established.Setting:Dietary survey in a US national cohort: the Continuing Survey of Food Intakes by Individuals (CSFII), 1994?96.Subjects:Men and non-pregnant, non-lactating women aged 21?45 years in the CSFII who provided two multiple-pass 24-hour recalls, height and weight(n= 3755).Results:Average rEI was 77% of pTEE in men, and 64% of pTEE in women. Calculated cut-offs were rEI <40% or >160% of pTEE (?2 SD) and <70% or >130% of pTEE (?1 SD), respectively. Use of only the ?1 SD cut-offs, not the ?2 SD cut-offs, resulted in a relationship between rEI and body weight similar to what was expected (based on an independently calculated relationship between rEI and measured TEE). Exclusion of rEI outside either the ?2 SD (11% of subjects) or ?1 SD (57% of subjects) cut-offs did not affect mean reported macronutrient intakes, but did markedly affect relationships between dietary composition and body mass index.Conclusions:When examining relationships between diet and health, use of ?1 SD cut-offs may be preferable to ?2 SD cut-offs for excluding inaccurate dietary reports.

We review evidence regarding the influence of dietary fat, fiber, the glycemic index and sugar on energy intake and body weight. Although data from comprehensive long-term studies are lacking, published investigations suggest that the previous focus on lowering dietary fat as a means for promoting negative energy balance has led to an underestimation of the potential role of dietary composition in promoting reductions in energy intake and weight loss. More randomized clinical trials are needed to examine the relative utility of different putative dietary factors in the treatment of obesity.

As a result of the rising prevalence of overweight and obesity in the United States, more and more individuals are attempting to lose weight by modifying dietary intake. Total energy intake remains the most important factor in dietary interventions, but strategies based on emerging factors such as glycemic index, fiber intake, dietary variety, and energy density may improve efficacy and tolerability of energy restriction. Many popular diets remain untested by prospective randomized trials, and concerns exist about the effects of these diets on long-term health issues such as lipid profiles, micronutrient intake, bone health, and renal function. Recent developments in the dietary treatment of obesity are reviewed, and potential mechanisms by which dietary strategies influence weight loss and compliance with reductions in energy intake are discussed.

Objectives:To investigate the effects of oats, a cereal rich in soluble fiber, on body composition changes and dietary compliance during consumption of a weight loss diet.Methods:Subjects were 41 healthy men and women aged 18 to 78 years. Weight maintenance energy requirements were established over two weeks during consumption of a control diet with low soluble fiber content. Subjects then consumed a hypocaloric diet for six weeks, either consuming a low soluble fiber control diet or a diet containing 45 g/1000 kcal rolled oats, a whole grain cereal rich in soluble fiber (mean energy deficit −895 ± 18 kcal/day relative to weight maintenance energy requirements). Changes in body fat and fat-free mass were determined by underwater weighing, and dietary compliance was assessed using the urinary osmolar excretion rate technique. In a final phase of the study, subjects ate ad libitumfor six months, and changes in body weight and composition were monitored.Results:There was no significant effect of the oat-containing diet on body weight or composition changes during the hypocaloric regimen or in the subsequent ad libitumperiod. In addition, fecal energy excretion was not significantly different between groups. However, there were non-significant trends indicating reduced hunger in the oat group compared to controls (frequency of hunger 2.5±0.5 vs.3.6±0.4, P=0.1). In addition, fewer oat subjects were non-compliant (four versus seven subjects dropped out or had urinary osmolar excretions greater than 130% of values predicted from dietary intake), but again the difference was not significant.Conclusions:These results suggest that use of a cereal rich in soluble fiber in a closely monitored hypocaloric feeding regimen does not improve weight loss or dietary compliance. Further studies are needed to examine the possibility that cereals containing soluble fiber may have effects on hunger and dietary compliance that could be important in less tightly controlled protocols than the one described here.

β-Amyloid (Aβ) accumulation is believed to contribute to neuronal cell death in Alzheimer's disease. To understand the role of cAMP in the regulation of Aβ induced cell death, we used 8-chlorophenylthio-cAMP (8-CPT-cAMP, a cAMP analog) to raise intracellular cAMP levels. Exposure of rat cortical neurons to Aβ(25-35) resulted in a gradual increase in lactate dehydrogenase (LDH) over 48 h, which was preceded by a transient elevation in caspase-3-like activity. In the presence of 8CPT-cAMP, both caspase-3 activity and LDH release was significantly reduced. These data suggest that elevation of intracellular cAMP levels attenuate Aβ-induced neurotoxicity and may delay or prevent the onset of Aβ-induced neurode-generation.

McCRORY, MEGAN A., PAUL J. FUSS, NICHOLAS P. HAYS, ANGELA G. VINKEN, ANDREW S. GREENBERG, AND SUSAN B. ROBERTS. Overeating in America: association between restaurant food consumption and body fatness in healthy adult men and women ages 19 to 80. Obes Res. Purpose: To examine the association between the frequency of consuming restaurant food and body fatness in adults. Research Methods and Procedures: Usual free‐living dietary intake and the frequency of consuming food from seven different restaurant types (fried chicken, burger, pizza, Chinese, Mexican, fried fish, and “other”) were assessed by food frequency questionnaire in 73 healthy men and women [ages 19 to 80, body mass index (BMI) 18 to 331. In addition, body fatness (percent weight) was determined by hydrostatic weighing, and physical activity and other lifestyle parameters were assessed by questionnaire. The relationship between the frequency of consuming restaurant food and body fatness was determined after controlling for age, sex, and other confounders by using multiple regression techniques. Results: Restaurant food consumption averaged 7.5±8.5 (Standard Deviation) timedmonth. After controlling for age and sex, the frequency of consuming restaurant food was positively associated with body fatness (partial r= 0. 36, p= 0. 003). The strength of this association did not change after controlling for education level, smoking status, and alcohol intake, but after additionally controlling for physical activity, the partial rincreased to 0. 42 (p= 0. 004). Total daily intakes of energy, fat, and fiber were significantly associated with restaurant food consumption frequency (r = 0. 59, 0. 28, and −0.45, respectively, p= 0.02 to 0.0001). Discussion: The frequency of consuming restaurant food was positively associated with increased body fatness in adults. The increasing proportion of household food income spent on food prepared away from home in the United States may therefore help explain the rising national prevalence of obesity.

Research indicates that lower extremity muscle weakness in the elderly is consistently related to impaired mobility and fall risk. Reversible components of the muscle weakness of aging include underuse syndromes and undernutrition, both of which are prevalent in nursing home populations. The Boston FICSIT study is a nursing home‐based intervention to improve muscle strength through progressive resistance training of the lower extremities and/or multi‐nutrient supplementation in chronically institutionalized subjects aged 70–100. Baseline measurements of falls, medical status, psychological variables, functional status, nutritional intake and status, body composition, muscle mass and morphology, muscle function, and gait and balance are taken. The nursing home residents are then randomly assigned to one of four treatment groups for 10 weeks: (1) high intensity progressive resistance training of the hip and knee extensors 3 days per week; (2) multi‐nutrient supplementation with a 360‐kcal high carbohydrate, low fat liquid supplement every day; (3) a combination of groups (1) and (2); and (4) a control group. Both non‐supplemented groups receive a liquid placebo every day, and both non‐exercising groups attend three sessions of “leisure activities” every week in order to control for the attentional aspects of the exercise and nutritional interventions. At the end of the 10‐week period, all baseline measurements are re‐assessed.

A double‐blind study was conducted to determine between‐laboratory variability in the doubly labeled water method for measurement of total energy expenditure in humans, and to compare the accuracy and precision of three widely‐used procedures for calculating rates of carbon dioxide production from the original isotope data. Eighteen laboratories from five countries participated in the study. All laboratories were provided with five water standards containing varying amounts of 2H and 18O, and in addition 11 laboratories were provided with urine and dose specimens from one (six laboratories) or two (five laboratories) healthy elderly subjects of normal height and weight undergoing a calorimetric validation of the doubly labeled water method. The data from the five water standards were analyzed to predict between‐laboratory variability in the doubly labeled water technique in all laboratories. In addition, data from the subjects were analyzed using the “slope‐intercept”, “2‐point” and “modified” methods of calculation. The results confirm that the doubly labeled water method can be an accurate technique for the measurement of energy expenditure in adult human subjects in some laboratories. However, there was substantial between‐laboratory variability in the results and some laboratories returned physiologically impossible results. There was no significant effect of calculation procedure on the accuracy of the technique in this limited comparison, although the slope‐intercept procedure appeared to be more susceptible to analytical error than the other procedures. The isotope standards analyzed by participants in this study will be made available to other investigators on request.

The role of energy expenditure in the development of obesity remains unclear. This issue is examined using data from prospective studies of energy expenditure and obesity, the effects of overfeeding and diet composition on energy expenditure, and studies of the relationship between energy expenditure for physical activity and body composition. The combined results from these investigations strongly support the view that low energy expenditure can facilitate rapid weight gain in susceptible individuals. It is speculated that, in susceptible individuals, low energy expenditure for resting energy expenditure as well as physical activity are part of a range of mechanisms available for providing surplus energy for rapid weight gain. In addition, both cross‐sectional and intervention studies indicate that there is an equilibration between the level of energy expenditure for physical activity and body fat content. While genetic and other factors clearly play an important role in this relationship, it appears that a modest reduction in body fat content can be achieved by increasing energy expenditure for physical activity in physical exercise programs.