A reduced-calorie dietary pattern including a daily sweet snack promotes body weight reduction and body composition improvements in premenopausal women who are overweight and obese: a pilot study

Reduced-calorie diets are difficult to follow because they often require elimination of certain foods, leading to poor compliance and limited success. However, a low-calorie, nutrient-dense diet has the potential to accommodate a daily snack without exceeding energy requirements, even during weight loss. This pilot study evaluated the effects of a reduced-calorie diet including either a daily dark chocolate snack or a non-chocolate snack on anthropometric and body composition measurements. In a randomized clinical trial, 26 overweight and obese (body mass index ≥25 to ≤43) premenopausal women were assigned to a reduced-calorie diet that included either a daily dark chocolate snack or non-chocolate snack (n=13 per group) for 18 weeks. At baseline and end of study, body weight and waist and hip circumferences were measured along with fat mass, lean mass, and body fat percentage by dual-energy x-ray absorptiometry. Energy and macronutrient intakes were estimated from 4-day food records. Within- and between-group changes from baseline were analyzed using paired t tests and independent t tests, respectively. Women in both snack groups reduced estimated daily energy intake (P<0.001). Women in both the dark chocolate snack and non-chocolate snack groups, respectively, experienced decreases (P<0.001) in body weight (−5.1 vs −5.1 kg), hip circumference (−5.8 vs −5.4 cm), waist circumference (−5.7 vs −3.5 cm), fat mass (−3.9 vs −3.6 kg), and body fat percentage (−3.4% vs −3.1%), with no change in lean mass. Improvements in anthropometric and body composition measurements among overweight and obese premenopausal women can be achieved with a reduced-calorie diet including either a daily dark chocolate snack or non-chocolate snack.     

Weight change and the conservation of lean mass in old age: the Health, Aging and Body Composition Study

BACKGROUND: Weight loss may contribute to the loss of lean mass with age. OBJECTIVE: The objective was to evaluate the relation between weight loss or weight gain and changes in lean mass and fat mass in older adults. DESIGN: We observed changes in weight and body composition during a 4-y period in 2163 men (47%) and women (53%) aged 70-79 y in the Health, Aging and Body Composition Study cohort. Whole-body and appendicular bone-free lean mass and fat mass were measured by using dual-energy X-ray absorptiometry. RESULTS: Weight loss and weight gain were common. In both weight losers and weight gainers, changes in lean mass as a percentage of initial lean mass were substantially smaller than changes in fat mass as a percentage of initial fat mass. However, the difference between the change in lean mass and that in fat mass was more pronounced with weight gain than with weight loss, especially in men. Small amounts of lean loss and fat gain were noted with weight stability. In multivariate models, weight loss was strongly associated with lean mass loss in both men and women, especially in men whose weight loss was concurrent with a hospitalization. CONCLUSIONS: With weight change, a greater proportion of lean mass than of fat mass was conserved, but, especially in older men, significantly more lean mass was lost with weight loss than was gained with weight gain. These findings suggest that weight loss, even with regain, could accelerate sarcopenia in older adults.     

A Worksite Program for Overweight Middle-Aged Men Achieves Lesser Weight Loss With Exercise Than With Dietary Change

Objective To compare changes in total and regional body composition using dual energy X-ray absorptiometry (DEXA) after subjects lost weight through change in diet or exercise.Design A 12-month, randomized, controlled study of two weight-loss interventions — low-fat diet ad libitum or moderate, unsupervised exercise — in free-living, middle-aged men. Compliance was determined at monthly measurement sessions through food records and activity logs; DEXA scans were performed every 3 months.Subjects/setting Fifty-eight overweight men (mean body mass INDEX=29.0±2.6; mean AGE=43.4±5.7 years) recruited from a national corporation were assigned randomly to diet, exercise, or control groups.Interventions One group reduced dietary fat to 26.4% of energy intake but kept activity unchanged; another group self-selected aerobic exercise (three sessions per week at 65% to 75% maximum heart rate) but kept diet unchanged. A control group maintained weight.Main outcome measures At 12 months, measurements of weight, total and regional fat mass and lean mass, energy intake, and percentage dietary fat; physical activity indexes. Statistical analyses Results were analyzed using paired t tests and analysis of variance.Results Mean weight loss was 6.4±3.3 kg in dieters and 2.6+3.0 kg in exercisers; control subjects maintained weight. DEXA scans revealed that 40% of dieters’ weight loss was lean tissue; more than 80% of weight lost by exercisers was fat. Exercisers maintained limb lean tissue and lost fat mass.Conclusions Greater total weight and lean tissue loss occurred when subjects lost weight through a low-fat diet consumed ad libitum than when subjects participated in unsupervised aerobic exercise. Use of DEXA enabled identification of progressive total and regional changes in fat and lean tissue. J Am Diet Assoc. 1997; 97:37–42.     

Body composition and dietary intakes in adult celiac disease patients consuming a strict gluten-free diet

BACKGROUND: Celiac disease responds to dietary gluten withdrawal, but data on the long-term effects of gluten-free diets are discordant. OBJECTIVE: Our aim was to evaluate the nutritional status and body composition of adult celiac disease patients consuming a gluten-free diet who were in clinical, biochemical, and histologic remission. DESIGN: We studied 71 patients (51 women and 20 men; mean age: 27 y; range: 17-58 y) and 142 healthy control subjects matched by sex and age. The subjects' height, weight, body mass index, fat and lean mass, and bone mineral content (evaluated by dual-energy X-ray absorptiometry) were measured; a 3-d dietary questionnaire was administered; and total daily energy, fat, carbohydrate, and protein intakes were calculated. RESULTS: The weight, height, and body mass index of male celiac disease patients and the weight and body mass index of female celiac disease patients were significantly lower than the corresponding measurements in control subjects. The fat and lean mass of both male and female patients was significantly different from that of control subjects; however, bone mineral content was significantly lower only in females in whom celiac disease was diagnosed in adulthood. Total energy intake was lower in the patients than in the control subjects (9686 +/- 1569 and 11297 +/- 1318 kJ/d in males and 6736 +/- 1318 and 7740 +/- 1715 kJ/d in females), and the diet of the patients was unbalanced, with a higher percentage of energy as fat and a lower percentage of energy as carbohydrates. CONCLUSIONS: Although strictly compliant with their gluten-free diet and in complete remission, patients with celiac disease showed differences in body composition and dietary intakes compared with control subjects. Strict follow-up and dietary advice in terms of the choice and composition of foods seem necessary to prevent malnutrition.     

Body composition in HIV-infected women

Although loss of lean body mass is a common complication of human immunodeficiency virus (HIV) infection that can occur across the disease trajectory, few studies have characterized the body composition of HIV-infected women. We used bioelectrical impedance analysis to characterize the body composition of HIV-infected (n = 56) and uninfected (n = 12) women who were matched on percentage of ideal body weight. The HIV-infected women did not differ from the uninfected women by height-adjusted fat mass or body cell mass. Intergroup comparisons among the HIV-infected women showed that underweight women had significantly less fat mass than did normal-weight women but did not significantly differ with respect to body cell mass. Among all HIV-infected women, CD4(+) lymphocyte count was positively correlated with fat mass (r = 0.32, P = 0.01) but not with body cell mass. No significant correlations were found between any body-composition parameter and plasma viral load. Our findings suggest that, unlike men, HIV-infected underweight women show a preferential loss of fat mass and a relative preservation of body cell mass. This altered pattern of weight loss may relate to higher premorbid fat stores in women and/or hormonal differences.     

Relation of BMI to a dual-energy X-ray absorptiometry measure of fatness

Dual-energy X-ray absorptiometry (DXA) is a valid technique for measuring the fat, bone and lean (muscle, organs and water) masses of the body. We evaluated relationships of BMI (kg/m2) with independent measurements of fat and lean masses using DXA in 226 adult volunteers. The evaluation was an application of a general approach to compositional data which has not previously been used for describing body composition. Using traditional regression analyses, when lean mass was held constant, BMI varied with fat mass (men r 0.75, P < 0.05; women r 0.85, P < 0.05); when fat mass was held constant, BMI varied with lean mass (men r 0.63, P < 0.05; women r 0.47, P < 0.05). In contrast, a regression model for compositional data revealed that BMI was: (a) strongly associated with log fat mass in both sexes (b1 4.86, P < 0.001 for all women and b1 5.96, P < 0.001 for all men); (b) not associated with bone mass, except in older men; (c) related to lean mass in women but not in men (b3 -4.04, P < 0.001 for all women and b1 -2.59, P < 0.15 for all men). Women with higher BMI tended to have more fat mass and more lean mass than women with lower BMI. Men with higher BMI had more fat mass but similar lean mass to men with lower BMI. Investigators need to be alert to the inaccuracy of BMI to assign a fatness risk factor to individuals, especially among women.     

Effects of birth cohort and age on body composition in a sample of community-based elderly

BACKGROUND: The effect of the recent obesity epidemic on body composition remains unknown. Furthermore, age-related changes in body composition are still unclear. OBJECTIVE: The objective was to simultaneously examine the effects of birth cohort and age on body composition. DESIGN: A total of 1786 well-functioning, community-based whites and blacks (52% women and 35% blacks) aged 70-79 y from the Health, Aging, and Body Composition Study underwent dual-energy X-ray absorptiometry annually from 1997 to 2003. RESULTS: At baseline, mean +/- SD percentage body fat, fat mass, and lean mass (bone-free) were 28 +/- 5%, 24 +/- 7 kg, and 56 +/- 7 kg, respectively, for men and 39 +/- 6%, 28 +/- 9 kg, and 40 +/- 6 kg for women. Mixed models were used to assess the effects of cohort and age-related changes on body composition. Later cohorts in men had a greater percentage body fat (0.32% per birth year, P < 0.0001) than did earlier cohorts. This cohort effect was due to a greater increase in fat mass than in lean mass (0.45 kg and 0.17 kg/birth year, respectively). With increasing age, percentage body fat in men initially increased and then leveled off. This age-related change was due to an accelerated decrease in lean mass and an initial increase and a later decrease in fat mass. Similar but less extreme effects of cohort and age were observed in women. CONCLUSIONS: The combination of effects of both birth cohort and age leads to bigger body size and less lean mass in the elderly.     

Rate of fat gain is faster in girls undergoing early adiposity rebound

OBJECTIVE: To determine the changes in body composition (fat and lean mass) occurring in children during adiposity rebound (AR). RESEARCH METHODS AND PROCEDURES: Thirty-nine girls, 3 to 6 years of age at baseline, underwent yearly DXA scans for 2 years. An additional DXA scan was obtained 4 to 5 years after baseline. Age at AR was determined by modeling, and the velocity of change in height, weight, fat mass, and lean mass was estimated for each child using random coefficient models. Girls with an AR <5 years of age were classified as having an early AR, and those having an AR > or =5 years were classified as late AR. RESULTS: Although body composition was similar at age 5, by age 9, girls with an early AR were significantly taller (3.5% more) and heavier (14.4%), with greater fat mass (50%) and percentage body fat (27%) than girls with a later AR. In addition, more girls were overweight according to BMI (18% vs. 6%) or percentage body fat (29% vs. 11%) at this time, despite no differences at baseline. Annual velocity of fat mass gain was over 2-fold higher in early compared with late rebounders (17.1% vs. 6.5%, p < 0.0001), with no difference in lean mass velocity (13.1% vs. 12.5%, p = 0.116). DISCUSSION: Differences in BMI during AR were caused specifically by alterations in body fat and not by alterations in lean mass or height. Children undergoing early AR gained fat at a faster rate than children who rebounded at a later age.     

低体重和肥胖儿童身体成分特点及脂肪肌肉含量与骨密度相关性研究

目的 探讨低体重和肥胖儿童身体成分特点及其脂肪肌肉含量与骨密度的相关性.方法 选择2015年6月至2016年6月于眉山市妇幼保健院儿保门诊体检的5~7岁儿童为研究对象,按体质量指数(BMI)分为低体重组、肥胖组和对照组,测量身体成分各项指标,包括体脂比、全身脂肪含量、肌肉含量及局部和全身骨密度,并对结果进行分析.结果 同性别儿童低体重组的体脂比、全身脂肪含量、肌肉含量及局部和全身骨密度均分别明显低于对照组,二者之间差异均具有统计学意义(t=3.076~3.326,均P<0.05);同性别儿童对照组的体脂比、全身脂肪含量、肌肉含量及局部和全身骨密度均分别明显低于肥胖组,二者之间差异均具有统计学意义(t=2.998~3.427,均P<0.05).经Logistic回归分析:低体重组儿童的肌肉含量与不同部位骨密度均呈正相关性(r=0.779~0.889,均P<0.05);肥胖组男性儿童的肌肉含量与下肢骨密度、体脂比和全身脂肪含量与躯干骨密度均呈正相关性(r=0.779~0.882,均P<0.05),肥胖组女性儿童肌肉含量与上肢骨密度,以及体脂比、全身脂肪含量和肌肉含量与下肢骨密度均呈正相关性(r=0.781~0.901,均P<0.05);对照组儿童的肌肉含量与不同部位骨密度均呈正相关性(r=0.779~0.912,均P<0.05),对照组女性儿童的体脂比、全身脂肪含量和肌肉含量均与下肢骨密度和全身骨密度均呈正相关性(r=0.805~0.912,均P<0.05).结论 与正常儿童相比,低体重和肥胖儿童身体成分构成,各指标与骨密度的相关关系明显不同于正常儿童.在对儿保门诊儿童管理中,体重、体脂比、全身脂肪含量、肌肉含量的变化均是需要关注的重要指标,从而促进其骨骼健康发育.     

Resting energy expenditure in reduced-obese subjects in the National Weight Control Registry.

BACKGROUND: Weight loss in obese subjects is associated with a reduction in resting metabolic rate (RMR). Whether the reduction can be explained solely by a reduction in lean body mass remains controversial. OBJECTIVE: Our objective was to determine whether the reduction in RMR after weight loss was proportional to the decrease in lean mass alone or was greater than could be explained by body composition. DESIGN: We measured the RMR, fasting respiratory quotient (RQ), and body composition in 40 reduced-obese subjects [ie, 7 men and 33 women who had lost > or = 13.6 kg (30 lb) and maintained the loss for > or = 1 y] enrolled in the National Weight Control Registry and 46 weight-matched control subjects (9 men, 37 women). RESULTS: A stepwise multiple regression found lean mass, fat mass, age, and sex to be the best predictors of RMR in both groups. After adjusting RMR for these variables, we found no significant difference in RMR (5926 +/- 106 and 6015 +/- 104 kJ/d) between the 2 groups (P = 0.35). When we adjusted fasting RQ for percentage body fat and age, the reduced-obese group had a slightly higher (0.807 +/- 0.006) RQ than the control group (0.791 +/- 0.005, P = 0.05). This may have been due to the consumption of a diet lower in fat or to a reduced capacity for fat oxidation in the reduced-obese group. CONCLUSION: These results show that in at least some reduced-obese individuals there does not seem to be a permanent obligatory reduction in RMR beyond the expected reduction for a reduced lean mass.     

Fat mass measured by DXA varies with scan velocity

OBJECTIVE: To study the influence of scan velocities of DXA on the measured size of fat mass, lean body mass, bone mineral content and density, and total body weight. RESEARCH METHODS AND PROCEDURES: The subjects were 71 healthy white adults, 38 women and 33 men. The mean age was 41.7 +/- 13.5 years and body mass index was 28.6 +/- 5.6 kg/m(2). The subjects were scanned consecutively in slow, medium, and fast scan mode by a Lunar DPX-IQ DXA scanner. RESULTS: Throughout the body mass index and sagittal height ranges, scanned lean body mass significantly decreased with higher scan velocity and lean body mass was 2.7% lower in fast than in medium mode (p < 0.0001). In contrast, fat mass, percentage of body fat, and bone mineral contents were higher with increasing scan velocity. Areas not analyzed by the scanner, so called blue spots, increased with scan velocity and sagittal height, and their presence significantly enhanced the error. Body weight estimated by DXA in slow mode was -0.8% lower than scale weight in the women (p < 0.001) and -0.2% in men (not significant), and the difference was greater with increasing scan velocity. DISCUSSION: Scan velocity significantly influences the measured fat mass size, lean body mass, bone mineral content, and body weight. To obtain the most accurate results, slow mode is preferable and fast scans should be avoided. Future studies should report and take scan velocity into consideration.     

Effect of highly active antiretroviral therapy on fat, lean, and bone mass in HIV-seropositive men and women.

BACKGROUND: Alterations in body composition have been reported in HIV-positive adults receiving highly active antiretroviral therapy (HAART), but the magnitude and potential determinants of these changes are unclear. OBJECTIVE: We compared total and regional body composition, as measured by dual-energy X-ray absorptiometry, in 203 HIV-positive men and 62 HIV-positive women according to HAART. DESIGN: This was a cross-sectional analysis of a cohort study of nutrition and HIV infection. RESULTS: After adjustment for age, weight, race, and exercise habits, total weight and fat mass did not differ significantly in men or women by HAART. Trunk fat was greater in men (1.0 kg; P < 0.001) and women (1.4 kg; P = 0.005) and leg fat was lower in men (-1.0 kg; P < 0.001) and women (-1.5 kg, P = 0.005) receiving HAART than in those not. This corresponded to a greater percentage of total fat mass located in the trunk (men: 7.5%, P < 0.001; women: 5.1%, P = 0.02). Lean mass was also greater with longer duration of HAART in men (P < 0.002). In men receiving HAART, total and regional bone mineral content were less than in the men not receiving HAART (P < 0.001). These effects increased with longer duration of HAART. Protease inhibitors were associated with the largest differences in regional fat. CONCLUSIONS: HAART is associated with redistribution of fat mass from the legs to the trunk, despite no significant differences in total fat mass or weight. In men, HAART is also associated with a reduction in bone mineral content, suggesting that HAART increases the risk of central obesity and osteoporosis.     

Body composition in asymptomatic HIV-infected men: cross-sectional and prospective assessment

Data on body composition changes in HIV infected patients is sparse and controversial. The aim of this study was to assess body composition in asymptomatic HIV-infected men with normal body weight in comparison to healthy HIV-negative control men and to investigate possible body composition changes in HIV-positive patients over a 2-year observation period. One hundred eight asymptomatic seropositive men, aged 19-62 years, and 20 healthy sex, age and weight - matched controls were recruited for the cross-sectional part of the study. Fifty-eight of the HIV+ patients were followed up for 2 years. Body weight, BMI, Bone Mineral Content (BMC), body Fat mass (Fat), % Fat, body Lean mass (Lean) and % Lean was recorded for each subject at the beginning and at the end of the follow-up period. The same analysis was repeated separately for arms, trunk and legs. HIV+ men had increased fat mass and reduced lean mass compared to controls (%Fat in HIV+ 24.3, %Fat in controls 19.2, p=0.012; %Lean in HIV+ 72.1, %Lean in controls 77.0, p=0.014). Lean mass was lower in extremities while fat mass was higher in the trunk region in HIV+ in comparison to controls, irrespective of antiretroviral therapy. Longitudinally, patients with higher baseline %Fat (>24.2, median) presented 20% decrease in fat mass while patients with lower baseline %Fat (< or =24.2) showed a smaller, non-significant decrease in fat mass accompanied by a significant decrease (2.52%) in lean mass. Fat loss occurred in all subjects predominantly in the extremities (16.5-36.45% loss), with relative preservation of trunk fat. It is concluded that otherwise asymptomatic HIV+ men exhibit subtle body composition changes involving reduced lean mass and increased central fat mass. The pattern of weight loss over time depends on baseline fat store: patients with adequate fat stores lose predominantly fat while patients with lower baseline fat stores lose both fat and lean mass. In the entire cohort, there is a tendency towards central adiposity, with the majority of fat being lost from the extremities, a picture resembling metabolic x syndrome.     

Weight loss and body-composition changes in men and women infected with HIV

BACKGROUND: The nature of body-composition changes in HIV-associated weight loss is unclear. OBJECTIVE: We examined the relation between the initial percentage of body fat and the composition of weight loss in men and women with HIV infection. DESIGN: HIV-positive adults were seen at semiannual clinic visits, at which time weight, fat, and fat-free mass were determined. The unit of analysis was the person-interval. RESULTS: Five hundred fifty-one persons contributed 2266 intervals of data, of which 311 (14%) were intervals in which weight loss was >/= 5% of initial (start of interval) weight. Of these, 208 (67%) intervals met the criteria for analysis (123 from men and 85 from women). Loss of fat-free mass was dependent on the initial percentage of body fat in the men with < 32% body fat. A plot of the initial percentage of body fat compared with loss of fat-free mass (kg) suggested a nonlinear relation over the range of body fat examined. There was no clear relation between the initial percentage of body fat and loss of fat-free mass in the women. CONCLUSIONS: In men with HIV-associated weight loss, the weight lost as fat-free mass depends on the initial percentage of body fat at low levels of body fat but appears to be independent of initial percentage of body fat at high levels of body fat. In women with HIV-associated weight loss who have normal-to-high body fat stores, loss of fat-free mass is independent of the initial percentage of body fat.     

ApoE4 Is Associated with Lower Body Mass,Particularly Fat Mass,in Older Women with Cognitive Impairment

A lower body mass is associated with the progression of Alzheimer’s disease (AD) and the risk of mortality in patients with AD; however, evidence of genetic determinants of decreased body mass in cognitively impaired older adults is limited. We therefore investigated the genetic effect of APOE-ε4 on body composition in older adults with mild cognitive impairment (MCI) and early-to-moderate-stage AD. A total of 1631 outpatients (aged 65–89 years) with MCI and early-to-moderate-stage AD were evaluated for the association between body composition and APOE-ε4 status. After adjusting for covariates, including cognitive function evaluated with the Mini-Mental State Examination, the presence of the APOE-ε4 was associated with lower weight (β = −1.116 ± 0.468 kg per presence, p = 0.017), fat mass (β = −1.196 ± 0.401 kg per presence, p = 0.003), and percentage of body fat (β = −1.700 ± 0.539% per presence, p = 0.002) in women but not in men. Additionally, the impact of APOE-ε4 on measures of body composition in women was more remarkable in MCI than in AD patients. The presence of the APOE-ε4 allele was associated with lower fat mass, particularly in women with MCI, independent of cognitive decline.     

Body composition measured by dual-energy X-ray absorptiometry in patients who have undergone small-intestinal resection

BACKGROUND: Patients who have undergone resection of the small intestine have lower body weight than do healthy persons. It remains unclear whether it is the body fat mass or the lean tissue mass that is reduced. OBJECTIVE: We compared body-composition values in patients who had undergone small-intestinal resection with reference values obtained in healthy volunteers, and we studied the relation between body-composition estimates and the net intestinal absorption of energy. DESIGN: In a cross-sectional study, we included 20 men and 24 women who had undergone small-intestinal resection and had malabsorption of energy > 2000 kJ/d. Diagnoses were Crohn disease (n = 37) and other conditions (n = 7). Body composition was estimated by dual-energy X-ray absorptiometry, and data were compared with those from a reference group of 173 healthy volunteers. Energy absorption was measured during 48-h balance studies by using bomb calorimetry, and individual values were expressed relative to the basal metabolic rate. RESULTS: Body weight and body mass index in patients were significantly (P < 0.05) lower than the reference values. Fat mass was 6.4 kg (30%) lower (95% CI: -8.8, -3.9 kg), but lean tissue mass was only slightly and insignificantly lower (1.5 kg, or 3.3%; 95% CI: -3.7, 0.60 kg). Weight, body mass index, and body-composition estimates by dual-energy X-ray absorptiometry did not correlate significantly with the net energy absorption relative to the basal metabolic rate, expressed as a percentage. CONCLUSIONS: Patients who had undergone small-intestinal resection had significantly lower body weights and body mass indexes than did healthy persons, and they had significant changes in body composition, mainly decreased body fat mass.     

Regional,but not total,body composition changes in overweight and obese adults consuming a higher protein,energy-restricted diet are sex specific

Secondary analyses of data from 2 studies were used to assess the effects of protein intake and sex on diet-induced changes in body composition. The primary hypothesis was that the changes of body composition via energy restriction (ie, lean body mass [LBM], fat mass [FM], and bone) would be sex and diet specific. For 12 weeks, 43 male (study 1) and 45 female (study 2) overweight and obese adults consumed an energy-deficit diet (750 kcal/d less than energy needs) containing either 0.8 (normal protein [NP], 21 men and 23 women) or 1.4 g protein?kg⁻¹?d⁻¹ (high protein [HP], 22 men and 22 women). Body composition measurements were performed at preintervention and postintervention. Over time, all research participants lost weight, LBM, and FM. Independent of protein intake, the men lost more LBM in the trunk (−0.9 vs −0.5 kg) and less in the legs (−1.5 vs −1.1 kg) compared with the women (P < .05). Independent of sex, the HP group lost less LBM in the trunk and legs than the NP group. These sex and protein intake responses resulted in the NP men losing the most LBM in the legs and the NP women losing the most LBM in the trunk. Over time, men lost more FM (−5.0 vs −3.9 kg) from the trunk and less from legs (−1.7 vs −2.1 kg) than women (P < .05), which resulted in a greater decrease of the android-to-gynoid fat ratio for the men. Protein intake did not influence these sex-specific responses or have any independent effects on changes in FM. In addition, protein intake did not influence bone mineral density responses over time; bone mineral density was reduced in women, but not in men. These findings indicate that higher protein intake during weight loss promotes the retention of LBM in both the trunk and legs despite the sex-specific changes in these body regions.     

Body composition in childhood: effects of normal growth and disease

Body composition in children is of increasing interest within the contexts of childhood obesity, clinical management of patients and nutritional programming as a pathway to adult disease. Energy imbalance appears to be common in many disease states; however, body composition is not routinely measured in patients. Traditionally, clinical interest has focused on growth or nutritional status, whereas more recent studies have quantified fat mass and lean mass. The human body changes in proportions and chemical composition during childhood and adolescence. Most of the weight gain comprises lean mass rather than fat. In general, interest has focused on percentage fat, and less attention has been paid to the way in which lean mass varies within and between individuals. In the general population secular trends in BMI have been widely reported, indicating increasing levels of childhood obesity, which have been linked to reduced physical activity. However, lower activity levels may potentially lead not only to increased fatness, but also to reduced lean mass. This issue merits further investigation. Diseases have multiple effects on body composition and may influence fat-free mass and/or fat mass. In some diseases both components change in the same direction, whereas in other diseases, the changes are contradictory and may be concealed by relatively normal weight. Improved techniques are required for clinical evaluations. Both higher fatness and reduced lean mass may represent pathways to an increased risk of adult disease.     

Association of waist circumference with muscle and fat mass in adults with a normal body mass index

BACKGROUND/OBJECTIVESWe aimed to investigate the association of waist circumference (WC) with body composition among individuals with a normal body mass index (BMI) to distinguish muscle and fat mass, as both affect health differently.SUBJECTS/METHODSWe analyzed dual-energy X-ray absorptiometry data (derived from the Korean National Health and Nutrition Survey, which includes information on fat and lean mass) of 7,493 adults with a normal BMI. Subjects were categorized into four groups of increasing WC. The fourth group was defined as being centrally obese. Each number of subjects are as follows: 1,870, 695, 231, and 39 among men and 3,054, 1,100, 406, and 98 among women. We conducted a sex-stratified linear regression analysis of body composition according to WC group after adjustments for covariates.RESULTSWe observed a positive association of body fat with increasing WC in both men and women (all P for trend: < 0.001). The adjusted mean values for percent body fat with 95% confidence intervals (CIs) according to the four WC groups in ascending order were 17.8 (17.5–18.3), 21.0 (20.6–21.5), 22.1 (21.5–22.8), and 25.1 (24.2–26.1) in men and 29.7 (29.4–30.0), 32.0 (31.6–32.3), 32.9 (32.4–33.4), and 34.7 (33.2–36.1) in women. However, there was an inverted J-shaped association between muscle mass and WC. The fourth group had a higher percent body fat and lower muscle mass than other groups. The adjusted mean values for appendicular skeletal muscle mass index (kg/m²) with 95% CIs according to the four WC groups in ascending order were 7.55 (7.51–7.59), 7.62 (7.56–7.68), 7.65 (7.56–7.74), and 7.22 (7.04–7.41) in men and 5.83 (5.80–5.85), 5.96 (5.92–6.00), 6.03 (5.96–6.10), and 5.88 (5.73–6.03).CONCLUSIONSThere was a positive association between body fat and WC among individuals with normal BMI; conversely there was an inverted J-shaped association between lean body mass and WC. Our findings support the WC measurement should be included in obesity evaluations for adults with a normal BMI.