Increase In Total Body Fat Research Articles

Weight Control: It Takes a Village

PHYSIOLOGY About 250 million adults worldwide are obese, a condition that puts them at great risk for diabetes, heart disease, and other serious health problems. Although remarkable progress has been made in understanding the physiological and environmental factors that regulate body weight in mammals, much remains to be learned. A new study in mice points to a surprising participant in body weight control: the community of bacteria (microbiota) that colonize the gut. Backhed et al. found that when they introduced the gut microbiota of normal mice into a special strain of “germ-free” mice, the recipients showed a 60% increase in total body fat within 2 weeks, even though they had eaten less and exhibited an increased metabolic rate. The microbiota appeared to promote fat storage by stimulating the synthesis of triglycerides in the liver and their deposition in adipocytes (fat cells). Based on their results, the authors hypothesize that changes in microbial ecology prompted by Western diets or differences in microbial ecology between individuals living in Western societies may affect predisposition toward obesity. — PAK Proc. Natl. Acad. Sci. U.S.A. 101 , 15718 (2004).

Weight gain, adiposity, and eating behaviors among adolescent females on depot medroxyprogesterone acetate (DMPA)

ObjectiveTo identify risk factors for weight gain and explore body composition and eating behaviors among adolescent females initiating depot medroxyprogesterone acetate (DMPA). MethodsA longitudinal study was conducted in 43 adolescent females beginning DMPA. Data collection at baseline, 3, and 6 months included structured interview; measurement of height, weight, and percent body fat; and assessment of dietary restraint, disinhibition, and appetite. ResultsBlack and white subjects did not differ in baseline weight or body composition. At 6 months, black subjects had a 4.2% increase in weight (mean weight gain=2.9 kg; P=0.003) and a 12.5% increase in body fat (mean fat gain =2.5 kg; P<0.001). In contrast, white subjects had a 1.2% increase in weight (mean weight gain=0.9 kg; P=0.32) and a 1.2% increase in body fat (mean fat gain of 0.5 kg; P=0.54). Baseline weight (P<0.001), study visit (P=0.005), age (P=0.006), eating restraint (P=0.005), eating disinhibition (P<0.001), and other medications (P<0.001) were predictive of weight gain in black subjects. Only baseline weight (P<0.001) was predictive in white subjects. Higher baseline weight (adjusted odds ratio (AOR)=1.2, 95% confidence interval (CI)=1.1,1.3) was a risk factor for gaining >2.2 kg the first 3 months. Black race (AOR=7.8, 95% CI=1.5, 66.2) and younger age at menarche (AOR=0.6, 95% CI=0.3, 0.9) were risk factors for gaining >2.2 kg the second 3 months. Appetite decreased in the study sample reaching statistical significance in black subjects. ConclusionsOur data suggest that black and white adolescents differ in the quantity, timing, and predictors of weight gain on DMPA. DMPA-associated weight gain is paralleled by increases in total body fat, while appetite decreases on DMPA.

Preferential Mesenteric Fat Accumulation and Enhanced Portal Free Fatty Acid Delivery in a High-Carbohydrate Diet Fed Rats

The regulation of adipose tissue distribution is an important problem in view of the close epidemiological and metabolic associations between centralized fat accumulation and disease. However, the majority of studies concerning adipose tissue distribution and metabolic disorders have focused on subjects already being obese. In this study, the effects of a high-carbohydrate diet (CHO) and a high-fat diet (FAT) on mass and function of mesenteric adipose depot, drained by the mesenteric vein, was examined in the pre-obese rat model. After 4 weeks of iso-energy feeding, the ratio of mesenteric adipose tissue weight to non-mesenteric was significantly greater in the CHO-fed group than in the FAT-fed group. Incorporation of orally administrated 3H-glucose into the mesenteric depot was more rapid in the CHO-fed group than in the FAT-fed group, but its incorporation into the non-mesenteric depot was similar between the two dietary groups. Arterial and mesenteric concentrations of free fatty acid and triglyceride of the CHO-fed group were significantly higher than those of the FAT-fed group. Gene expression of PPAR-γ and UCP-2 was similar among adipose depots, and there was no significant difference between the two dietary groups. In conclusion, dietary carbohydrate was preferentially incorporated into the total lipid in mesenteric adipose tissue. Without an increase in total body fat, CHO feeding for 4 weeks reinforces incorporation of dietary glucose into mesenteric depot, resulting in an increases of relative mesenteric adipose mass and portal FFA delivery.

Visceral adipose tissue in women: longitudinal study of the effects of fat gain, time, and race.

To determine the effects of fat gain, time, and race on the accumulation of visceral adipose tissue (VAT) in a group of normal-weight premenopausal women. Sixty-five women participated in the study (32 African American and 33 white). The mean age of subjects was 34 +/- 6 years (range, 22 to 47 years). Eligible subjects were women who had body mass indices <25 kg/m(2) at baseline and who had completed evaluations at baseline and at follow-up year 1, without intervention. A subset of subjects was reevaluated annually for up to 4 years. Body composition was assessed by DXA, and VAT was determined from a single computed tomography scan. A linear mixed model was used to examine changes in VAT over time, with total body fat as a covariate Total fat mass was not significantly different between races at baseline and increased significantly in both groups over time (p < 0.001). Time-related increases in total body fat were greater in African-American women (p < 0.01). VAT was significantly higher in white women at baseline (p < 0.01) and increased significantly over time in both races (p < 0.01), but remained higher in white women (p < 0.001). Increases in VAT, relative to total body fat, were greater than the increases in total body fat over time, independent of age and race (p < 0.001). Gaining total body-fat mass results in a higher increase in VAT, relative to total body fat, regardless of race and age, although African-American women maintain a lower VAT levels across time.

Assessment of skeletal muscle triglyceride content by (1)H nuclear magnetic resonance spectroscopy in lean and obese adolescents: relationships to insulin sensitivity, total body fat, and central adiposity.

The metabolism and composition of skeletal muscle tissue is of special interest because it is a primary site of insulin action and plays a key role in the pathogenesis of insulin resistance. Intramyocellular (IMCL) triglyceride stores are an accessible form of energy that may decrease skeletal muscle glucose utilization, thereby contributing to impaired glucose metabolism. Because of the invasive nature of muscle biopsies, there is limited, if any, information about intramuscular lipid stores in children. The development of (1)H nuclear magnetic resonance (NMR) spectroscopy provides a unique noninvasive alternative method that differentiates intracellular fat from intercellular fat in muscle tissue. The present study was performed to determine whether IMCL and extramyocellular (EMCL) lipid contents are increased early in the development of juvenile obesity and to explore the relationships between IMCL and EMCL to in vivo insulin sensitivity, independently of total body fat and central adiposity in obese and nonobese adolescents. Eight nonobese (BMI 21 kg/m(2), age 11-16 years) and 14 obese (BMI 35 +/- 1.5 kg/m(2), age 11-15 years) adolescents underwent 1) (1)H-NMR spectroscopy to noninvasively quantify IMCL and EMCL triglyceride content of the soleus muscle, 2) a 2-h euglycemic-hyperinsulinemic clamp (40 mU.m(-2).min(-1)) to assess insulin sensitivity, 3) a dual-energy X-ray absorptiometry scan to measure total percent body fat, and 4) magnetic resonance imaging to measure abdominal fat distribution. Both the IMCL and EMCL content of the soleus muscle were significantly greater in the obese adolescents than in the lean control subjects. A strong inverse correlation was found between IMCL and insulin sensitivity, which persisted and became even stronger after controlling for percent total body fat and abdominal subcutaneous fat mass (partial correlation r = -0.73, P < 0.01) but not when adjusting for visceral fat (r = - 0.54, P < 0.08). In obese adolescents, increase in total body fat and central adiposity were accompanied by higher IMCL and EMCL lipid stores. The striking relationships between both IMCL and EMCL with insulin sensitivity in childhood suggest that these findings are not a consequence of aging but occur early in the natural course of obesity.

Obesity, Diabetes, and Risk of Cardiovascular Disease in the Elderly

There is an age-related increase in total body fat and visceral adiposity until age 65 years that often is accompanied by diabetes or impaired glucose tolerance. The prevalence of type 2 diabetes increases progressively with age, peaking at 16.5% in men and 12.8% in women at age 75-84 years. Over age 65, diabetes or glucose intolerance was present in 30%-40% of Framingham Study subjects. There has been an alarming increase, of epidemic proportions, in both obesity and diabetes in the general population. Type 2 diabetes and obesity are both associated with a clustering of atherogenic risk factors, and when three or more are present it generally signifies an insulin resistance syndrome. This is promoted by weight gain and visceral adiposity. The risk of macrovascular disease is increased before glucose levels reach the diagnostic threshold for "diabetes," and 25% of newly diagnosed diabetics already have overt cardiovascular disease. In the Framingham Study, increased risk of cardiovascular disease was two-fold in men and three-fold in women, eliminating the female advantage over men for all outcomes except stroke. Coronary disease is the most common and lethal sequela, and unrecognized myocardial infarctions are three times more common in diabetic than nondiabetic men. Following a myocardial infarction, diabetes imposes a high rate of recurrence, heart failure, and death, more so in women than men. The risk of cardiovascular sequelae in diabetics is variable, the majority of events occurring in those with two or more additional risk factors. Because of the variable risk of cardiovascular disease in either the diabetic or obese person, risk stratification is necessary to determine the hazard of impending cardiovascular disease. This is readily accomplished with Framingham cardiovascular risk formulations. For persons with diabetes or obesity, the chief goal is to avoid the common cardiovascular sequelae. Comprehensive care should include not only normalization of the blood sugar, but also weight reduction, dietary fat restriction, strict blood pressure and lipid control, exercise, and avoidance of tobacco. Trial data indicate that preventive measures benefit obese diabetics even more than nondiabetics.

Efeitos do treinamento físico contra resistência sobre a composição corporal e a potência muscular em adultos deficientes de hormônio do crescimento

A síndrome da deficiência do hormônio do crescimento (GH) no adulto está bem estabelecida, assim como os benefícios da terapia de reposição com o GH recombinante. Dentre as alterações observadas nesses pacientes, as da composição corporal estão entre as mais estudadas, sendo caracterizadas por um aumento da gordura corporal total com predomínio de gordura no tronco, diminuição da massa magra, da força muscular e da água corporal total. Todas são quase completamente revertidas após tratamento de reposição com GH. Estudamos a composição corporal e potência muscular de 11 pacientes com deficiência de GH, antes e após serem submetidos a um programa de treinamento com exercícios contra resistência por 12 semanas, sem reposição com o GH. Avaliamos a composição corporal através de medidas de circunferências, dobras cutâneas, peso, altura, cálculo do índice de massa corporal e relação cintura-quadril. A potência muscular localizada foi avaliada em vários grupos musculares através de cinco exercícios numa unidade de exercícios musculares localizados, onde foi acoplado um tensiômetro. Após análise dos resultados, observamos que não houve mudança na composição corporal destes pacientes, em relação ao índice de massa corporal, relação cintura-quadril e peso. Quando estudamos separadamente a soma das dobras cutâneas centrais e periféricas, houve diminuição no volume da soma das dobras centrais. Em relação à força e potência muscular, não houve ganho de força de preensão manual medida através do dinamômetro (p&gt;0,05), já a potência mostrou um aumento significativo após treinamento (p&lt;0,01). Concluímos que esses pacientes, se submetidos a um programa de treinamento de exercícios contra resistência realizado em casa, ganham potência muscular e que esta forma de exercício é uma alternativa terapêutica para que possam melhorar sua qualidade de vida, quando não for possível a utilização do GH.

Elderly people with hypothalamic-pituitary disease and growth hormone deficiency: lipid profiles, body composition and quality of life compared with control subjects.

In healthy adults the secretion of growth hormone (GH) and insulin-like growth factor 1 (IGF-1) declines with ageing and body composition alters, particularly with an increase in total body fat. In elderly people, hypothalamic-pituitary disease can cause GH deficiency (GHD), compared with age matched controls. This study aimed to clarify whether GHD in the elderly is associated with differences in body composition, circulating lipid levels and quality of life (QOL) compared with control subjects. Twenty-seven elderly patients (14 males, mean age 71 years, range 65-83) with hypothalamic-pituitary disorders (23 pituitary tumours) and GHD (mean (SD) peak stimulated GH response 1.6 mIU/l (1.03) range 0.6-5) were studied. Twenty-five patients had been treated surgically (six cranial surgery, 19 transsphenoidal) and eight patients had received external cranial irradiation. Twenty-seven control subjects (14 males, mean age 72 years, range 65-86) were also studied. Weight, body mass index (BMI), total fat mass (FM, bioelectrical impedance), waist to hip ratio (WHR), serum IGF-1, fasting blood glucose and lipid profile were measured. QOL was assessed in both groups using five interviewer administered self-rating questionnaires: The Nottingham Health Profile, Short-Form 36, Hospital Anxiety and Depression Scale, Mental Fatigue Questionnaire and Life Fulfilment Scale. The GHD group also completed the Disease Impact Scale. The data (mean (SD)) from males and females were analyzed separately. The male patients had a higher BMI than controls, 28.9(4.5) vs. 25.2(2.3) kg/m2 (P = 0.01) but the BMI in the female patients and controls was similar. In the female patients compared with the controls, FM was higher 39. 4(6) vs. 33.1(8.3) % (P = 0.02), WHR was also higher 0.9(0.08) vs. 0. 83(0.09) (P = 0.03) and serum IGF-1 levels were lower 10.8(6.4) vs. 18.2(6.5) nmol/l (P = 0.01). However, in the male patients, FM, WHR and IGF-1 levels were similar to the controls. Fasting blood glucose was similar in both male and female patients and the controls. Two female patients and one male control subject were taking lipid-lowering agents and were therefore excluded from the analysis of lipid profiles. Total cholesterol, triglyceride, LDL cholesterol, HDL cholesterol and total cholesterol/HDL cholesterol ratio were not significantly different for both male and female patients compared with the controls. The 27 patients with GHD reported significantly less energy (P < 0.05), mobility (P < 0.05) and personal life fulfillment (P < 0.01) than the 27 controls. There were significantly more problems with emotional reaction (P < 0.01), social isolation (P < 0.05) and mental fatigue (P < 0.05). Additionally the GHD group reported more impairment in areas of social functioning (P < 0.05), general health (P < 0.05) and mental health (P < 0.05). The GHD group reported a modest degree of disease impact (mean score of 14.1). There were no significant differences in the domains of material life fulfillment, pain, sleep, physical functioning, vitality, anxiety, depression, self-esteem or role physical functioning compared with the controls. Compared with control subjects, the elderly female patients with hypothalamic-pituitary disease and GHD had a significantly higher total fat mass, with the WHR indicating a more central fat distribution and lower female serum IGF-1 levels. In contrast, elderly male patients had similar total fat mass, WHR and IGF-1 levels compared to the controls. There were no significant differences in the lipid profiles between male or female patients compared to controls. However, many of the male patients were receiving androgen replacement which might have influenced these results. Low HDL cholesterol concentrations are probably a better predictor of future cardiovascular disease than raised LDL cholesterol levels in the elderly population and these were similar in patients and controls for both

Obesity and Disturbed Lipoprotein Profile in Estrogen Receptor-α-Deficient Male Mice

Clinical case reports have documented disturbances of carbohydrate and lipid metabolism in aromatase deficient and estrogen resistant males. The aim of the present study was to explore the metabolic functions of estrogens in male mice and to dissect the estrogen receptor (ER) specificity of such effects. Total body fat content and serum levels of leptin were followed in ERα knockout (ERKO), ERβ knockout (BERKO), and ERα/β double knockout (DERKO) mice. Neither the total body fat nor serum leptin levels were altered in any group before or during sexual maturation. However, after sexual maturation ERKO and DERKO, but not BERKO, demonstrated a clear increase in total body fat and enhanced serum leptin levels. Serum cholesterol was increased and a qualitative change in the lipoprotein profile, including smaller LDL particles, was observed in ERKO and DERKO mice. In conclusion, ERα but not ERβ-inactivated male mice develop obesity after sexual maturation.

Continuation of Growth Hormone (GH) Replacement in GH-Deficient Patients during Transition from Childhood to Adulthood: A Two-Year Placebo-Controlled Study

Previous studies have demonstrated beneficial effects of GH replacement, in adults with GH deficiency (GHD), on body composition, physical fitness, and quality of life. These studies, however, concern patients with adult-onset GHD or childhood-onset (CO) patients enrolled several years after withdrawal of initial therapy. So far, the effects of continuation of GH-administration in patients with CO-GHD have not been examined. We studied a group of nineteen young adults (13 males+ 6 females; 16–26 yr old; mean age, 20.2 ± 0.65 yr) with CO-GHD, in a randomized, parallel, double-blind, placebo-controlled trial for 1 yr, followed by an open phase with GH for 1 yr. All patients received GH therapy at the start of study, and trial medication (GH/placebo) was given in a similar dose. Patients randomized to continued GH treatment exhibited no significant changes in any parameters tested, but intra- and interindividual variations in insulin-like growth factor (IGF)-I levels could suggest compliance problems. Discontinuation of GH for 1 yr resulted in a decrease in serum IGF-I, from 422.0 ± 56.8 to 147.8 ± 33.4 μg/L, in the placebo group (P = 0.003). After discontinuation of GH for 1 yr, an increase in total body fat (TBF, kg), measured by dual-energy x-ray absorptiometry scan, was seen[ placebo: 22.7 ± 2.7 to 26.5 ± 2.5 (P = 0.01); GH:16.2 ± 2.1 to 17.2 ± 2.1 (not significant)]. Resumption of GH after placebo was followed by increments in serum IGF-I (μg/L) [from 147.8 ± 33.4 to 452 ± 76 (P = 0.001)] and IGF-binding protein 3, as well as in fasting glucose (mmol/L) [4.9 ± 0.2 vs. 5.3 ± 0.2 (P = 0.03)]. After resumption of GH lean body mass (kg) increased [52.4 ± 4.9 vs. 60.7 ± 5.6 (P = 0.006)]. Likewise, resumption of GH therapy increased thigh muscle volume and thigh muscle/fat ratio, as assessed by computed tomography [muscle volume (cm2/10 mm): 118.2 ± 11.7 vs. 130.0 ± 10.9 (P = 0.002); muscle/fat ratio: 1.33 ± 0.24 vs. 1.69 ± 0.36 (P = 0.02)]. In conclusion, discontinuation of GH treatment in GHD patients, during the transition from childhood to adulthood, induces significant and potentially unfavorable changes in IGF-I and body composition, both of which are reversed after resumption of GH treatment. By contrast, continuation of GH therapy results in unaltered IGF-I and body composition. We recommend continuation of GH therapy in these patients, to be undertaken in collaboration between pediatricians and adult endocrinologists.

Aging, body composition, and lifestyle: the Fels Longitudinal Study

Changes in body composition in men and women occur with age, but these changes are affected by numerous covariate factors. The study examined patterns of change in body composition and determined the effects of long-term patterns of change in physical activity in older men and women and in menopausal status and estrogen use in women. Serial measures of height, weight, body mass index (BMI), total body fat (BF), percentage BF, and fat-free mass (FFM) from underwater weighing of 102 men and 108 women enrolled in the Fels Longitudinal Study were analyzed. Physical activity levels and menopausal status were included as covariates. There were significant age-related decreases in FFM and height and increases in total BF, percentage BF, weight, and BMI. Physical activity was associated with decreases in total BF, percentage BF, weight, and BMI in men and were associated with increases in FFM and decreases in total BF and percentage BF in women. Postmenopausal women had significantly higher total BF and percentage BF than did pre- and perimenopausal women. The longer the time since menopause the greater were the increases in weight, BMI, total BF, and percentage BF; however, estrogen use attenuated these increases. Low FFM can be improved by increased physical activity. The effects of an intervention program on body composition can be masked if only body weight or BMI is measured. The effects of physical activity were more profound in postmenopausal than in premenopausal women, and estrogen use had beneficial effects on body composition.

Smaller differences in total and regional adiposity with age in women who regularly perform endurance exercise.

Our aim was to determine if women who regularly perform endurance exercise demonstrate age-related elevations in body mass and adiposity. Ninety-five healthy females were studied: premenopausal (n = 28; mean +/- SE age 30 +/- 1 yr) and postmenopausal (n = 31; 56 +/- 1 yr) endurance-trained runners and premenopausal (n = 17; 29 +/- 1 yr) and postmenopausal (n = 19; 61 +/- 1 yr) sedentary controls. In the runners, body mass did not differ across age, but percent fat and fat mass were higher (P < 0.05) in the postmenopausal women. The age-related difference in total body fat, however, was only approximately 50% as great (P < 0.01) as that observed in the sedentary controls due in part to smaller age-related differences in central (truncal) fat. The higher fat mass in the postmenopausal runners was modestly (inversely) related to both exercise volume (r = -0.44, P < 0.01) and maximal oxygen consumption (r = -0.41, P < 0.01). The present findings provide experimental support for the hypothesis that women who regularly engage in vigorous endurance exercise may not gain body weight, undergo only a modest increase in total body fat, and do not demonstrate a significant elevation in central adiposity with age.

The effect of glucocorticoids on fat and lean tissue masses in giant cell arteritis

The aim of the present prospective study over a follow-up period of two years was to assess the influence of various doses of glucocorticosteroids on the total body fat and lean tissue masses and their regional distribution, using DXA technique, in twenty-four patients with giant cell arteritis (GCA). Treatment with glucocorticoids for two years, using high doses of prednisolone the first six months and lower doses thereafter, resulted in a significant increase in total body fat as well as in trunk fat expressed either as absolute values or as a proportion of body weight. The abnormal accumulation of fat mass remained also after switching to a low dose glucocorticoid schedule. There was no redistribution of fat from peripheral areas to central parts of the body and there was no depletion of lean tissue at peripheral sites. Elisabeth Nordborg, Division of Rheumatology, Sahlgenska University Hospital, S-413 45 Göteborg, Sweden

Growth Responses and Liver Changes in Juvenile Sunshine Bass (Morone chrysops×M. saxatilis) Associated with Dietary Protein and Lipid Level

Four isocaloric semi-purified diets containing 33 or 43% protein with either 13 or 16% lipid were fed to juvenile sunshine bass, Morone chrysops × M. saxatilis, (4.5 g initial weight) for 12 weeks. Fish fed 43% protein and 13% lipid gained significantly more weight than fish fed other diets. Both increased dietary protein or increased dietary lipid resulted in significant increases in total body fat but no change in body protein. Increasing the dietary protein level to 43% also resulted in significantly higher liver lipid content. Histological examination revealed a high degree of fatty infiltration in these livers, which was exacerbated at 16% dietary lipid. Protein efficiency ratios and apparent protein retention were greater in the 33% protein diets. Liver alanine aminotransferase (AAT) activities increased significantly when dietary protein increased. Replacing dextrin with lipid further increased AAT activity. Lipid weight gain and liver composition as well as enzyme activities are responsive to macr...

Do elevated levels of abdominal visceral adipose tissue contribute to age-related differences in plasma lipoprotein concentrations in men?

Age-related differences in body fat and more specifically in the accumulation of abdominal visceral adipose tissue were examined as a potential covariate for the alteration in the plasma lipoprotein profile found with aging. For that purpose, results from 79 young adults (aged 24.5 ± 4.0 years) were compared to 61 middle-aged men (54.7 ± 6.4 years). Younger men had significantly lower body fat mass and abdominal visceral adipose tissue area measured by computed tomography than middle-aged men ( P < 0.0001). Plasma cholesterol, triglyceride, apolipoprotein (apo) B, low density lipoprotein (LDL)-cholesterol and LDL apo B levels, as well as the ratio of plasma cholesterol to high density lipoprotein (HDL)-cholesterol were all significantly lower in younger men as compared to middle-aged men ( P < 0.001). The comparison of younger men to middle-aged men with comparable levels of abdominal visceral fat and total body fat eliminated the age-related differences in plasma triglyceride and in the ratio of plasma cholesterol to HDL-cholesterol, whereas the difference in plasma apolipoprotein B levels, although still significant, was largely reduced. Age-related differences in plasma cholesterol and in LDL-cholesterol levels were still observed after this matching procedure and the differences between age-groups were essentially of similar magnitude than before pairing. In summary, these results suggest that the deterioration of plasma lipoprotein profile observed in middle-aged men as compared to young adult men is partly mediated by concomitant increases in total body fat and abdominal visceral adipose tissue. However, other factors related to the aging process appear to be involved, particularly for the age-related increase in plasma LDL-cholesterol.

Estimation of body fat and lean tissue distribution by dual energy X-ray absorptiometry and abdominal body fat evaluation by computed tomography in Cushing's disease.

Body composition determined by dual energy x-ray absorptiometry and the abdominal visceral fat component determined by computed tomographic scanning were examined in women with Cushing's disease and compared with those in obese women with the same anthropometric parameters and those in nonobese women. Patients with Cushing's had no increase in total body fat or the trunk region (android) component, but had a higher intraabdominal fat area compared to the obese subjects. The total lean tissue mass was slightly reduced in Cushing's compared to that in the obese subjects due to a significant decrease in the muscle of the legs and arms; the reduced amounts of fat and lean tissue masses in the arms were the most significant findings in hypercortisolism. The body mineral and bone calcium contents were slightly reduced in Cushing's compared to those in the obese controls. Thus, although obese subjects had more fat and lean tissue and mineral masses than their normal weight counterparts, the Cushing's patients, with the same total fat mass and its components (except in the arms) as obese individuals, present total lean tissue and fractions, including body mineral and bone calcium contents, similar to those in nonobese subjects due to the depletion of the protein depots, as seen in hypercortisolism.

Obesity. Part I-Pathogenesis

Obesity--defined by a body mass index above 30 kg per m2--is a major problem for affluent nations. Its prevalence is higher in North America than in Europe--between 9% and 12% of the population. Reduced energy expenditure from exercise or metabolism or both may be an important contributory factor in the development of obesity because of a failure to reduce food intake sufficiently to maintain energy balance. A high ratio of abdominal circumference relative to gluteal circumference carries a twofold or greater risk of heart attack, stroke, hypertension, diabetes mellitus, gallbladder disease, and death. The effect of increased quantities of abdominal fat is greater than that of a similar increase in total body fat on the risks of ill health associated with obesity. Genetic factors appear to contribute about 25% to its etiology.

The effect of increased adiposity on food intake of juvenile rats

The regulation of feeding by body adiposity, as proposed by the lipostatic theory, has been well demonstrated in adult animals. However, mechanisms controlling long-term feeding in juvenile animals have not been well defined. In this study, increased adiposity was induced in young rats through oral gavage. Four-week-old rats were divided into three groups; ad lib feeding (100%-AL), tubefed 100% (100%-TF) or 150% (150%-TF) of ad lib intake. Animals were tube-fed these levels for one week. At the end of this period, one third of each group were killed and all remaining animals were returned to ad lib feeding for either 4 or 29 days later. During this recovery period, the 150%-TF group had significantly depressed food intakes for the first 4 days in comparison to the 100%-TF group. Afterwards, there were no significant differences between these two groups for the remainder of the study. Overfeeding induced significant increases in total body fat in the 150%-TF group (24.8 grams) in comparison to the 100%-AL group (11.0 grams) and the 100%-TF group (14.0 grams). By day five of recovery, only the 150% group exhibited a significant loss of body fat. Total carcass protein and ash were not different between groups at any period. At day 29 of recovery, there were no treatment differences in carcass weight or fat content. Loss of body fat from the 150%-TF rats was associated with the decline in caloric intake. It appears that food intake is affected by relative adiposity during the dynamic phase of growth.

Changes in the body composition of the surgical infant in the early postoperative period

The purpose of this study was to evaluate the effects of postoperative nutritional management on the body composition of infants after major surgery. We studied 13 full-term surgical infants (mean initial weight 2.88 +/- 0.19 kg; mean days postsurgery 5.0 +/- 0.5). Ten infants were receiving total parenteral nutrition and three were orally fed (mean caloric intake 84 +/- 4 kcal/kg/d; mean fluid intake 145 +/- 4 mL/kg/d). Total body water (TBW) was measured by isotope dilution using heavy oxygen (18O) labeled water (H2(18)O). Total body fat (TBF) was estimated from anthropometric data. Lean body mass (LBM) was calculated as follows: LBM = weight--TBF. Protein, fat, and carbohydrate accretion were determined by energy and macronutrient balance in conjunction with open-circuit indirect calorimetry. Body composition was reevaluated after an interval of seven days. Body weight increased from 2.88 +/- 0.19 to 3.00 +/- 0.19 kg, representing a mean growth velocity of 5.9 g/kg/d. Increments were observed in all body compartments but only the increase in TBF reached statistic significance (12.9 v 14% of body weight, P less than .05). TBW ranged from an initial value of 76.2 +/- 1.4% to a value of 75.5 +/- 1.4% at the end of the study. Protein, fat, and carbohydrate accretion (g/kg/d) during the seven-day study period were 1.62 +/- 0.13; 1.44 +/- 0.41, and 0.96 +/- 0.70, respectively. These data indicate that in the early postoperative period, the weight gain is secondary to both water and solid tissue accretion. Fat represents the major form of energy storage in the new tissues synthesized.(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of supplementation of the diet with highly palatable foods upon energy balance in the rat.

Full energy balance studies have been performed for 9 weeks on four groups of four adult female rats housed in a continuously running indirect calorimeter; for four weeks two of the groups received highly palatable foods in addition to a standard pelleted diet. A further sixteen groups, of which eight received the palatable foods, provided additional carcass composition data. All practicable precautions were taken to measure energy exchange accurately. Comparison of 'start-to-finish' apparent energy balance with carcass composition changes showed a systematic error of approx. +3% of energy throughput. This was most probably caused by losses of energy in food and excreta, which led to over-estimation of energy intake. Variations among individual balance periods added a standard error of approx. +/- 1%: the source of error here was probably imperfect matching of animals analysed at intermediate stages. The rats offered the palatable foods increased their metabolizable energy (m.e.) intake by 106 kJ/day, 51% of the control groups' intake, in the first week of supplementation. Over the whole 4 weeks of supplementation the increase was 64 kJ/day, or 31%. Withdrawal of the palatable foods led to an immediate fall in intake to about two-thirds of control level, and a return to control level over the next 2-3 weeks. Energy expenditure rose more slowly than intake, reaching a fairly steady level ca. 5 days after introduction of the palatable foods. Expenditure was then ca. 22 kJ/day above control level; an increase of 12% above control expenditure or, allowing for systematic and random errors, 33-37% of the additional m.e. intake. Expenditure returned to control level over the 2 weeks after ceasing supplementation. The experimental groups gained weight at a declining rate throughout the period of supplementation. The gain in live body weight at the end was ca. 32 g, but this comprised a carcass weight gain of 37 g and a loss of 5 g gastrointestinal tract contents. The carcass weight gain comprised 27 g fat (i.e. ca. 70% of the weight gained), 9 g lean tissue and 1 g additional water. The gain of carcass energy was 1100 kJ. There was a small increase in body length, an increase in liver weight, and an increase in the weight of the interscapular brown adipose tissue pad. Regression analysis showed that the increase in the weight of the interscapular brown adipose tissue pad reflected the increase in total body fat.(ABSTRACT TRUNCATED AT 400 WORDS)