Composition Of Weight Loss Research Articles

Associations between the proportion of fat-free mass loss during weight loss, changes in appetite, and subsequent weight change: results from a randomized 2-stage dietary intervention trial

Dynamic changes in body composition which occur during weight loss may have an influential role on subsequent energy balance behaviors and weight. The aim of this article is to consider the effect of proportionate changes in body composition during weight loss on subsequent changes in appetite and weight outcomes at 26 wk in individuals engaged in a weight loss maintenance intervention. A subgroup of the Diet, Obesity, and Genes (DiOGenes) study (n=209) was recruited from 3 European countries. Participants underwent an 8-wk low-calorie diet (LCD) resulting in ≥8% body weight loss, during which changes in body composition (by DXA) and appetite (by visual analog scale appetite perceptions in response to a fixed test meal) were measured. Participants were randomly assigned into 5 weight loss maintenance diets based on protein and glycemic index content and followed up for 26 wk. We investigated associations between proportionate fat-free mass (FFM) loss (%FFML) during weight loss and 1) weight outcomes at 26 wk and 2) changes in appetite perceptions. During the LCD, participants lost a mean±SD of 11.2±3.5 kg, of which 30.4% was FFM. After adjustment, there was a tendency for %FFML to predict weight regain in the whole group (β: 0.041; 95% CI: -0.001, 0.08; P=0.055), which was significant in men (β: 0.09; 95% CI: 0.02, 0.15; P=0.009) but not women (β: 0.01; 95% CI: -0.04, 0.07; P=0.69). Associations between %FFML and change in appetite perceptions during weight loss were inconsistent. The strongest observations were in men for hunger (r=0.69, P=0.002) and desire to eat (r=0.61, P=0.009), with some tendencies in the whole group and no associations in women. Our results suggest that composition of weight loss may have functional importance for energy balance regulation, with greater losses of FFM potentially being associated with increased weight regain and appetite. This trial was registered at clinicaltrials.gov as NCT00390637.

Associations between the rate, amount, and composition of weight loss as predictors of spontaneous weight regain in adults achieving clinically significant weight loss: A systematic review and meta-regression.

Weight regain following weight loss is common although little is known regarding the associations between amount, rate, and composition of weight loss and weight regain. Forty-three studies (52 groups; n=2379) with longitudinal body composition measurements were identified in which weight loss (≥5%) and subsequent weight regain (≥2%) occurred. Data were synthesized for changes in weight and body composition. Meta-regression models were used to investigate associations between amount, rate, and composition of weight loss and weight regain. Individuals lost 10.9% of their body weight over 13weeks composed of 19.6% fat-free mass, followed by a regain of 5.4% body weight over 44weeks composed of 21.6% fat-free mass. Associations between the amount (P<0.001) and rate (P=0.049) of weight loss and their interaction (P=0.042) with weight regain were observed. Fat-free mass (P=0.017) and fat mass (P<0.001) loss both predicted weight regain although the effect of fat-free mass was attenuated following adjustment. The amount (P<0.001), but not the rate of weight loss (P=0.150), was associated with fat-free mass loss. The amount and rate of weight loss were significant and interacting factors associated with weight regain. Loss of fat-free mass and fat mass explained greater variance in weight regain than weight loss alone.

Sex differences in the composition of weight gain and loss in overweight and obese adults

Sex differences in the ratio of fat mass (FM):fat-free mass (FFM) during weight change should differentially affect the extent of weight change during energy imbalance in men and women. In the present study, we determined FM and FFM contents by dual-energy X-ray absorptiometry and calculated the P-ratios (protein energy/total energy) of excess weight and weight loss during a randomised controlled trial of four commercial weight loss regimens. Overweight and obese women (n 210) and men (n 77) were studied at baseline and at 2 and 6 months during weight loss on four dietary regimens: Dr Atkins' New Diet Revolution; The Slim-Fast Plan; Weight-Watchers programme; Rosemary Conley's Diet and Fitness Plan. At baseline, the percentage of FFM (%FFM) and P-ratios of excess weight were 40 % and 0·071 for men and 27 % and 0·039 for women. At 2 months, men had lost twice as much weight as women and three times more FFM than women, indicating higher FFM content and P-ratios of weight loss for men, 0·052, than for women, 0·029, with no dietary effects. Between 2 and 6 months, the rate at which weight was lost decreased and the %FFM of weight loss decreased to similar low levels in men (7 %) and women (5 %): i.e. P-ratios of 0·009 and 0·006, respectively, with no dietary effects. Thus, for men compared with women, there were greater FFM content and P-ratios of weight change, which could partly, but not completely, explain their greater weight loss at 2 months. However, protein-conserving adaptations occur with increasing weight loss and over time, more extensively in men, eventually eliminating any sex difference in the composition of weight loss.

Influence of Changes in Body Composition and Adaptive Thermogenesis on the Difference between Measured and Predicted Weight Loss in Obese Women

Background: There is a difference between measured and predicted weight loss in obese patients. This might be explained by the composition of weight loss, adaptive thermogenesis, or poor compliance. Patients and Methods: 48 overweight and obese female patients (31.5 ± 6.1 years; BMI 35.4 ± 4.4 kg/m²) were investigated before and 13.9 ± 2.4 weeks after dietary treatment (1,000 kcal/day). Body composition was measured by air-displacement plethysmography and resting energy expenditure (REE) by indirect calorimetry. Physical activity was assessed using electronic pedometers in order to calculate total energy expenditure from REE and physical activity level (PAL). Fat mass (FM) and fat-free mass (FFM) were converted into caloric equivalents using 9.45 kcal/g FM and 1.13 kcal/g FFM. Predicted weight loss was calculated by Wishnofsky’s ‘7,700 kcal/kg rule’. Results: Weight (–8.4 ± 3.9 kg; p < 0.001), FM (–7.8 ± 3.6 kg; p < 0.001), and FFM (–0.6 ± 2.0 kg; p < 0.05) decreased with caloric restriction. Measured weight loss was only 44% of the predicted value. Since FM contributed to 87% of weight loss, the energy deficit/kg weight loss was considerably higher (9,098 ± 2,349 kcal/kg) than the assumed 7,700 kcal/kg. Adaptive thermogenesis after weight loss was significant in 26 of 48 women (–3.2 ± 1.2 kcal per kg FFM; p < 0.001). Conclusion: 14% of the difference between measured and predicted weight loss was explained by the higher proportion of FM in weight loss and 38% by adaptive thermogenesis (in 54% of the women). Thus, poor compliance was responsible for about 50% of the difference between measured and predicted weight loss only.

Effects of dietary protein on the composition of weight loss in post-menopausal women.

To determine whether a hypocaloric diet higher in protein can prevent the loss of lean mass that is commonly associated with weight loss. An intervention study comparing a hypocaloric diet moderately high in protein to one lower in protein. Study measurements were taken at the Wake Forest University General Clinical Research Center (GCRC) and Geriatric Research Center (GRC). Twenty-four post-menopausal, obese women (mean age = 58 +/- 6.6 yrs; mean BMI = 33.0 +/- 3.6 kg/m2). Two 20-week hypocaloric diets (both reduced by 2800 kcal/wk) were compared: one maintaining dietary protein intake at 30% of total energy intake (1.2-1.5 g/kg/d; HI PROT), and the other maintaining dietary protein intake at 15% of total energy (0.5-0.7 g/kg/d; LO PROT). The GCRC metabolic kitchen provided lunch and dinner meals which the women picked up 3 days per week and ate outside of the clinic. Body composition, including total body mass, total lean mass, total fat mass, and appendicular lean mass, assessed by dual energy x-ray absorptiometry, was measured before and after the diet interventions. The HI PROT group lost 8.4 +/- 4.5 kg and the LO PROT group lost 11.4 +/- 3.8 kg of body weight (p = 0.11). The mean percentage of total mass lost as lean mass was 17.3% +/- 27.8% and 37.5% +/- 14.6%, respectively (p = 0.03). Maintaining adequate protein intake may reduce lean mass losses associated with voluntary weight loss in older women.

Long–Term Effects of High‐and Low‐Glycemic Load Energy‐Restricted Diets on Metabolic Adaptation and the Composition of Weight Loss

The effects of high glycemic load (HG) and low glycemic load (LG) diets on resting metabolic rate (RMR) and body composition changes in response to caloric restriction (CR) remains controversial. Objective To examine the effects of two CR diets differing primarily in glycemic load on RMR and the % of weight lost as fat and fat free mass (FFM). Methods One year randomized controlled trial of HG and LG diets at 30% CR in 29 healthy overweight adults (mean±SD, age 35±5y; BMI 27.5±1.5 kg/m2). All food was provided for 6 mo, and self‐administered for the next 6 mo. Outcome measures included RMR, fat and FFM. Results There was no significant effect of diet on change in RMR after accounting for the decreases in body fat and FFM, at any time point (p=0.51 at 3 mo, p=0.56 at 6 mo and p=0.85 at 12 mo). In the subgroup of individuals who lost &gt;5% body weight the LG diet group had a significantly higher percentage of weight loss as fat and a significantly lower percentage of weight loss as FFM compared to the HG group (p&lt;0.05). Conclusions This study found no evidence for differential RMR response to weight loss between the HG and LG diets. However, for a given weight loss, the LG diet resulted in greater fat loss and less FFM loss.Support NIH grants NGA‐3U01‐AG20480, K23DK61506, #H150001; USDA 58‐1950‐4‐401

Is a calorie a calorie?

The aim of this review was to evaluate data regarding potential thermodynamic mechanisms for increased rates of weight loss in subjects consuming diets high in protein and/or low in carbohydrate. Studies that compared weight loss and energy expenditure in adults consuming diets high in protein and/or low in carbohydrate with those in adults consuming diets low in fat were reviewed. In addition, studies that measured the metabolizable energy of proteins, fats, and carbohydrates were reviewed. Diets high in protein and/or low in carbohydrate produced an approximately equal to 2.5-kg greater weight loss after 12 wk of treatment. Neither macronutrient-specific differences in the availability of dietary energy nor changes in energy expenditure could explain these differences in weight loss. Thermodynamics dictate that a calorie is a calorie regardless of the macronutrient composition of the diet. Further research on differences in the composition of weight loss and on the influence of satiety on compliance with energy-restricted diets is needed to explain the observed increase in weight loss with diets high in protein and/or low in carbohydrate.

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

The nature of body-composition changes in HIV-associated weight loss is unclear. We examined the relation between the initial percentage of body fat and the composition of weight loss in men and women with HIV infection. 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. 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. 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.

Popular diets: a scientific review.

Introduction Weight loss is a major concern for the US population. Surveys consistently show that most adults are trying to lose or maintain weight (1). Nevertheless, the prevalence of overweight and obesity has increased steadily over the past 30 years. Currently, 50% of all adult Americans are considered overweight or obese (2,3). These numbers have serious public health implications. Excess weight is associated with increased mortality (4) and morbidity (5). It is associated with cardiovascular disease, type 2 diabetes, hypertension, stroke, gallbladder disease, osteoarthritis, sleep apnea and respiratory problems, and some types of cancer (6,7). Most people who are trying to lose weight are not using the recommended combination of reducing caloric intake and increasing physical activity (1). Although over 70% of persons reported using each of the following strategies at least once in 4 years, increased exercise (82.2%), decreased fat intake (78.7%), reduced food amount (78.2%,) and reduced calories (73.2%), the duration of any one of these behaviors was brief. Even the most common behaviors were used only 20% of the time (8). Obesity-related conditions are significantly improved with modest weight loss of 5% to 10%, even when many patients remain considerably overweight (6). The Institute of Medicine (9) defined successful long-term weight loss as a 5% reduction in initial body weight (IBW) that is maintained for at least 1 year. Yet data suggest that such losses are not consistent with patients’ goals and expectations. Foster (10) reported that in obese women (mean body mass index [BMI] of 36.3 6 4.3) goal weights targeted, on average, a 32% reduction in IBW, implying expectations that are unrealistic for even the best available treatments. Interestingly, the most important factors that influenced the selection of goal weights were appearance and physical comfort rather than change in medical condition or weight suggested by a doctor or health care professional. Is it any wonder that overweight individuals are willing to try any new diet that promises quick, dramatic results more in line with their desired goals and expectations than with what good science supports? The proliferation of diet books is nothing short of phenomenal. A search of books on Amazon.com using the key words “weight loss” revealed 1214 matches. Of the top 50 best-selling diet books, 58% were published in 1999 or 2000 and 88% were published since 1997. Many of the top 20 best sellers at Amazon.com promote some form of carbohydrate (CHO) restriction (e.g., Dr. Atkins’ New Diet Revolution, The Carbohydrate Addict’s Diet, Protein Power, Lauri’s Low-Carb Cookbook). This dietary advice is counter to that promulgated by governmental agencies (US Department of Agriculture [USDA]/Department of Health and Human Services, National Institutes of Health) and nongovernmental organizations (American Dietetic Association, American Heart Association, American Diabetes Association, American Cancer Society, and Shape Up America!). What is really known about popular diets? Is the information scientifically sound? Are popular diets effective for weight loss and/or weight maintenance? What is the effect, if any, on composition of weight loss (fat vs. lean body mass), micronutrient (vitamin and mineral) status, metabolic parameters (e.g., blood glucose, insulin sensitivity, blood pressure, lipid levels, uric acid, and ketone bodies)? Do they affect hunger and appetite, psychological well-being, and reduction of risk for chronic disease (e.g., coronary heart disease, diabetes, and osteoporosis)? What are the effects of these diets on insulin and leptin, long-term hormonal regulators of energy intake and expenditure? The objective of this article is to review the scientific literature on various types of popular diets based on their macronutrient composition in an attempt to answer these questions (see Appendix for diet summaries). Address correspondence to Dr. Janet King, U.S. Department of Agriculture, Agricultural Research Service, Western Human Nutrition Research Center, University of California, 1 Shield Avenue, Building Surge IV, Room 213, Davis, CA 95616. E-mail: jking@ whnrc.usda.gov Copyright © 2001 NAASO

The control of partitioning between protein and fat during human starvation: its internal determinants and biological significance.

Human subjects vary in the extent to which their body's protein and fat compartments are mobilized for fuel during starvation. Although an inverse association between the initial adiposity and the contribution of protein as fuel during starvation has been known for nearly a century, interest in the quantitative importance and functional significance of the initial percentage fat as a determinant of biological variation in energy-partitioning between protein and fat (and hence in determining the partitioning characteristic of the individual) is relatively recent. The present paper addresses these issues by revisiting the classic Minnesota experiment of semi-starvation and refeeding from a standpoint of system physiology. In a quantitative analysis of the relationship between the initial body composition (ration FAT0: fat-free mass (FFM)0) and the composition of weight loss (ratio delta FAT: delta FFM) in the thirty-two men in the Minnesota study, the arguments are put forward that the fraction of FFM lost when the fat stores reach total depletion is independent of the initial percentage fat, and that this fraction represents the 'dispensable' component of the protein compartment that is compatible with life (i.e. the protein energy-reserve, rp). The concepts are developed that (1) the initial percentage body fat (which reflects the initial ratio FAT0:FFM0) provides a 'memory of partitioning' which dictates the control of partitioning between protein and fat in such a way that both the protein energy-reserve (rp) and the fat energy-reserve (rf) each complete depletion simultaneously, a strategy that would ensure maximum length of survival during long-term food scarcity, and that (2) variability in the relative sizes of these two energy reserves (i.e. in rf:rp) could, in addition to the initial percentage fat, also contribute to human variability in energy-partitioning. The basic assumptions underlying this re-analysis of the Minnesota data, and the concepts that are derived from it, have been integrated in the simple mathematical model for predicting the partitioning characteristic of the individual. This model is used to explain how variability in the fraction of the protein compartment that could function as an energy reserve (rp) can be as important as the initial percentage fat in determining inter-individual variability in protein-sparing during the early phase of starvation, in fuel partitioning during prolonged starvation, or in the maximum percentage weight loss during starvation. The elucidation of factors underlying variability in the size of the protein energy-reserve may have important implications for our understanding of the pathophysiology of starvation and age-associated susceptibility to muscle wasting, and in the clinical management of cachexia and obesity.

PHYSIOLOGICAL ADAPTATIONS TO A WEIGHT-LOSS DIETARY REGIMEN AND EXERCISE PROGRAMS IN WOMEN 267

The purpose of this study was to examine various physiological and performance parameters to a 12 wk weight-loss diet program with/without endurance exercise or endurance plus resistance exercise. 31 overweight women were matched and randomly placed into either a control group (C; n=6) or one of three dietary groups; a diet group (D; n=8), a diet + aerobic exercise (3× week) group (DE; n=9); and a diet + aerobic + strength training (3× week) group (DES; n=8). Body composition, physical performance, and serum lipids were measured before and after the program. After 12 wks, the 3 dietary groups demonstrated a significant (P≤0.05) reduction in body mass(BM),% body fat, and fat mass. No significant differences were observed in the magnitude of loss between groups or loss in fat-free mass. DE and DES significantly increased maximal oxygen consumption, and DES increased in maximal (1-RM) strength in the bench press and squat. Weight loss resulted in a reduction in total serum cholesterol (C), LDL-C and HDL-C between dietary groups with DE and DES significantly decreasing total C, DE demonstrating a significant decline in LDL C, and D and DES demonstrating a significant decrease in HDL-C. Serum glucose, BUN, triglyceride, testosterone, and cortisol concentrations were unchanged except for significantly elevated cortisol concentrations in DE at 6 and 12 weeks. These data indicate that the absolute amount and composition of weight-loss during moderate caloric restriction is not altered by inclusion of aerobic or aerobic plus resistance exercise. However, diet in conjunction with endurance and strength training can induce adaptations in aerobic capacity and muscular strength despite significant reductions in BM. Sponsored by Matol Botanical International LTD, Montreal, Canada.

Loss of fat, water, and protein during very low calorie diets and complete starvation

The magnitude and composition of weight loss obtained in obese women on two forms of very low calorie protein-supplemented diets (Cambridge diet, Dresden drink) as well as by complete starvation has been investigated. With the VLCD, nitrogen equilibrium was reached on the 10th day of fasting, the cumulative nitrogen balance also being compensated. Nearly half of the body weight loss is due to loss of fat. In order to assess the benefit of fasting regimes, we propose to measure at least two parameters which are independent of each other, e.g., nitrogen balance and total body water. Both types of VLCD were equally effective, safe, and acceptable in achieving rapid body weight reduction.

Composition of postnatal weight loss and subsequent weight gain in small for dates newborn infants.

Using a sucrose and deuterium oxide dilution technique body water compartments and solids were serially determined in small for dates newborn infants at birth, at the moment of maximum postnatal weight loss and on recovery of birth weight. Compositions of weight loss and subsequent weight gain were calculated from the differences in body water compartments and solids between the first and the second and the second and the third study, respectively. Birth weight of the infants was 1.55 +/- 0.46 kg (mean +/- SD) (N = 7), gestational age was 35.7 +/- 3.1 weeks. Results show that despite changes in extra- and intracellular water volumes during weight loss, total body water volume and solids per unit of body weight remained remarkably constant throughout the study. Compositions of weight loss and subsequent weight gain were similar to body composition. This suggests that in small for dates newborn infants postnatal weight loss is the result of catabolism rather than dehydration and subsequent weight gain is the result of growth rather than rehydration.

Effects of aerobic exercise and weight loss on riboflavin requirements of moderately obese, marginally deficient young women

In a previous study, exercise was shown to increase riboflavin requirements of active, normal weight young women. The present study examined the effect of exercise and weight loss on riboflavin status of moderately overweight women. The experiment was designed as a two-period cross-over with an initial base-line period and two 5-wk metabolic periods. The basic diet contained 1200 kcal with a riboflavin concentration of 0.8 mg/1000 kcal. Exercise consisted of a program of dance exercise. Riboflavin depletion, as measured by increased erythrocyte glutathione reductase activity coefficients and decreased urinary excretion of riboflavin, occurred during both nonexercise and exercise periods. Erythrocyte glutathione reductase activity coefficients increased from a base-line mean of 1.28 ± 0.11 to 1.40 ± 0.12 during nonexercise and to 1.49 ± 0.16 during exercise. Urinary excretion of riboflavin fell from 48 ± 12% of intake during base-line to 30 ± 13% during nonexercise and to 19 ± 6% during exercise. Riboflavin depletion was not related to the rate or composition of weight loss or to change in aerobic capacity.

Effects of Fasting on Muscle Protein Turnover, the Composition of Weight Loss, and Energy Balance of Obese and Nonobese Zucker Rats

The effects of prolonged fasting on the composition of weight loss and the rates of muscle protein synthesis and degradation were compared in obese and nonobese (lean) rats. Lean rats weighing 400 g could survive only 10 days of fasting, whereas obese rats weighing 550 g could survive 60 days. Weight loss was similar in both phenotypes over the first 10 days of fasting (15 g/day), but the composition of weight loss differed. Obese rats lost nearly twice as much lipid but only one-fifth as much body protein as lean rats. The fasting metabolic rate [kilocalories/(day·kilograms0.75)] was similar in both phenotypes. This finding indicates a slower decline in metabolic rate during fasting in obese rats, since maintenance requirements are greater in lean rats. In fed rats, the fractional rates of muscle protein synthesis (FRS) and breakdown (FRB) were slightly higher in obese rats. Fasting reduced muscle protein synthesis in both phenotypes. In obese rats, however, the FRS declined more slowly than in lean rats. On the other hand, FRB decreased in fasted obese rats but greatly increased in fasted lean rats. It was concluded that the better protein retention and slower decline in metabolic rate in fasted obese rats were related to their different regulation of muscle protein synthesis and breakdown during fasting.muscle protein turnover fasting obesity Zucker rats 3-methylhistidine

Composition of weight loss in morbidly obese patients after gastric bypass

Optimal treatment of morbid obesity requires reduction of excess body fat while minimizing lean tissue loss. In order to determine if gastric bypass surgery satisfies both these requirements, we have studied changes in body composition and weight loss in adult (mean age = 33 years) morbidly obese patients (14 males, 68 females) after gastric bypass surgery. The preoperative weight of this cohort was 136 ± 27 (SD) kg, which was 228 ± 37% of ideal body weight by actuarial standards. Lean body mass (LBM) was estimated from potassium-40 measurements obtained from a wholebody potassium-40 counter and by urine creatinine excretion on a subgroup of 20 patients. The average weight loss at 3, 6, and 12 months after surgery was 25, 35, and 46 kg, respectively. The weight loss phase lasted approximately 1 year, at which time 34% of the initial weight was lost and the percentage of loss of excess weight above ideal body weight plateaued at 61%. LBM accounted for 32% of the total weight loss at 1 month, 11% at 6 months, and only 3% at the end of 1 year. The percentage of body weight represented by LBM increased from 35% prior to surgery to 51% by 18 months after gastric bypass. Actual LBM content increased steadily after the first month following surgery. Mean total weight loss following three different surgical procedures for gastric bypass did not differ significantly. Gastric bypass surgery appears to satisfy the objectives of reducing excess weight contributed by fat while minimizing lean tissue loss in morbidly obese patients.

Growth in sheep. I. The chemical composition of the body

SUMMARYFifteen sheep were fedad libitumfrom 2 days to 27 months of age, and another 15 sheep were each fed exactly half the average amount consumed by the first group, age for age. The body composition of each sheep (water, fat, protein, energy) was estimated from tritiated water space on 13 occasions during this period.To describe the course of growth in individual sheep in terms of the relationships between the various body components and body weight, a model was set up in which 4 phases of growth were distinguished, viz. the milk-feeding phase, the period of rumen development, and a prefattening followed by a fattening ruminant phase. Each phase was represented by a linear equation.Except for phase 1, mean composition within each phase differed significantly between well-fed animals and those which had been given a restricted diet. Individual animals differed in the body weight at which the final phase commenced; the average weight wasca.31 kg. Fat storage was zero or negative during the main period of rumen development; otherwise the fat and therefore energy content of weight gain increased from phase to phase. The protein and water content of gain was high in phases 1 and 2 and decreased subsequently.Calculations based on data in the literature indicated that, in phase 4, the composition of weight loss was the same as that of weight gain. It is also suggested that the body weight at which this fattening phase commences is related to mature weight, with animals of large ultimate size starting to fatten at heavier body weights than those of small ultimate size.The application of the results to the determination of nutrient requirements is discussed.

Gross composition of weight loss in obese men on a 400-calorie diet

Gross composition of weight loss in obese men on a 400-calorie diet

Composition and caloric density of weight loss during caloric restriction in cold.

Two groups of six men each lived for 14 days in a cold chamber at 60 F (15.6 C); activity was sedentary and only athletic shorts were worn. During this period one group, A, was semi-starved (600 kcal/day) and the other, B, was completely starved (0 kcal/day). Changes in body composition were measured and caloric density of weight loss was calculated. Mean weight loss was 5.66 kg for A, and 8.56 kg for B. Composition and caloric density of weight loss was almost identical for both groups. Composition of weight loss with regard to fat, protein and water was 39, 10, and 51% for A; 39, 11, and 49% for B. Caloric density was 3.91 kcal/g for A and 4.06 kcal/g for B. Submitted on February 20, 1961