Paula C. Chandler-Laney

Exercise Training Prevents Regain of Visceral Fat for 1 Year Following Weight Loss

The purpose of this study was to determine what effect aerobic and resistance exercise training has on gain of visceral fat during the year following weight loss. After being randomly assigned to aerobic training, resistance training, or no exercise training, 45 European‐American (EA) and 52 African‐American (AA) women lost 12.3 ± 2.5 kg on a 800 kcal/day diet. Computed tomography was used to measure abdominal subcutaneous and visceral adipose tissue, whereas total fat and regional fat (leg, arm, and trunk) were measured by dual energy X‐ray absorptiometry after weight loss and 1 year following the weight loss. Because not all the subjects adhered to the 2 time/week 40 min/day exercise training during the 1‐year follow‐up, subjects were divided into five groups for analysis: aerobic adherers, aerobic nonadherers, resistance adherers, resistance nonadherers, and no exercise. No significant differences were observed between the aerobic training and resistance training adherers for any variable. However, the aerobic (3.1 kg) and resistance (3.9 kg) exercise adherers gained less weight than any of the other three groups (all >6.2 kg). In addition, the two exercise adherence groups did not significantly increase visceral fat (<0.8%) as compared with the 38% increase for the two nonadhering exercise groups and the 25% for the nonexercise group. In conclusion, as little as 80 min/week aerobic or resistance training had modest positive effects on preventing weight regain following a diet‐induced weight loss. More importantly, both aerobic and resistance training prevented regain of potentially harmful visceral fat.

High intake of palatable food predicts binge-eating independent of susceptibility to obesity: an animal model of lean vs obese binge-eating and obesity with and without binge-eating

Objective:To determine the stability of individual differences in non-nutritive ‘junk’ palatable food (PF) intake in rats; assess the relationship of these differences to binge-eating characteristics and susceptibility to obesity; and evaluate the practicality of using these differences to model binge-eating and obesity.Design:Binge-eating prone (BEP) and resistant (BER) groups were identified. Differential responses to stress, hunger, macronutrient-varied PFs, a diet-induced obesity (DIO) regimen and daily vs intermittent access to a PF+chow diet, were assessed.Subjects:One hundred and twenty female Sprague–Dawley rats.Measurements:Reliability of intake patterns within rats; food intake and body weight after various challenges over acute (1, 2, 4 h), 24-h and 2-week periods.Results:Although BEP and BER rats did not differ in amount of chow consumed, BEPs consumed >50% more intermittent PF than BERs (P<0.001) and consistently so (α=0.86). BEPs suppressed chow but not PF intake when stressed, and ate as much when sated as when hungry. Conversely, BERs were more affected by stress and ate less PF, not chow, when stressed and were normally hyperphagic to energy deficit. BEP overeating generalized to other PFs varying in sucrose, fat and nutrition content. Half the rats in each group proved to be obesity prone after a no-choice high fat diet (DIO diet) but a continuous diet of PF+chow normalized the BEPs high drive for PF.Conclusion:Greater intermittent intake of PF predicts binge-eating independent of susceptibility to weight gain. Daily fat consumption in a nutritious source (DIO-diet; analogous to a fatty meal) promoted overeating and weight gain but limiting fat to daily non-nutritive food (PF+chow; analogous to a snack with a low fat meal), did not. The data offer an animal model of lean and obese binge-eating, and obesity with and without binge-eating that can be used to identify the unique physiology of these groups and henceforth suggest more specifically targeted treatments for binge-eating and obesity.

Effect of Dietary Adherence with or without Exercise on Weight Loss: A Mechanistic Approach to a Global Problem

CONTEXT Weight loss using low-calorie diets produces variable results, presumably due to a wide range of energy deficits and low-dietary adherence. OBJECTIVE Our objective was to quantify the relationship between dietary adherence, weight loss, and severity of caloric restriction. DESIGN AND SETTING Participants were randomized to diet only, diet-endurance training, or diet-resistance training until body mass index (BMI) was less than 25 kg/m(2). PARTICIPANTS Healthy overweight (BMI 27-30) premenopausal women (n = 141) were included in the study. INTERVENTIONS An 800-kcal/d(-1) diet was provided, and the exercise groups were engaged in three sessions per week. MAIN OUTCOMES Dietary adherence, calculated from total energy expenditure determined by doubly labeled water measurements and dual-energy x-ray absorptiometry body composition changes, and degree of caloric restriction were determined. RESULTS All groups had similar weight loss (approximately 12.1 +/- 2.5 kg) and length of time to reach target BMI (approximately 158 +/- 70 d). Caloric restriction averaged 59 +/- 9%, and adherence to diet was 73 +/- 34%. Adherence to diet was inversely associated to days to reach target BMI (r = -0.687; P < 0.01) and caloric restriction (r = -0.349; P < 0.01). Association between adherence to diet and percent weight lost as fat was positive for the diet-endurance training (r = 0.364; P < 0.05) but negatively correlated for the diet-only group (r = -0.387; P < 0.05). CONCLUSIONS Dietary adherence is strongly associated with rates of weight loss and adversely affected by the severity of caloric restriction. Weight loss programs should consider moderate caloric restriction relative to estimates of energy requirements, rather than generic low-calorie diets.

Fat Distribution, Aerobic Fitness, Blood Lipids, and Insulin Sensitivity in African-American and European-American Women

The purpose of this study was to determine independent relationships of intra‐abdominal adipose tissue (IAAT), leg fat, and aerobic fitness with blood lipids and insulin sensitivity (Si) in European‐American (EA) and African‐American (AA) premenopausal women. Ninety‐three EA and ninety‐four AA with BMI between 27 and 30 kg/m2 had IAAT by computed tomography, total fat and leg fat by dual‐energy X‐ray absorptiometry, aerobic fitness by a graded exercise test, African admixture (AFADM) by ancestry informative markers, blood lipids by the Ektachem DT system, and Si by glucose tolerance test. Independent of age, aerobic fitness, AFADM, and leg fat, IAAT was positively related to low‐density lipoprotein–cholesterol (LDL‐C), cholesterol‐high‐density lipoprotein (HDL) ratio, triglycerides (TGs), and fasting insulin (standardized β varying 0.16–0.34) and negatively related to HDL‐cholesterol (HDL‐C) and Si (standardized β −0.15 and −0.25, respectively). In contrast, independent of age, aerobic fitness, AFADM, and IAAT, leg fat was negatively related to total cholesterol, LDL‐C, cholesterol‐HDL ratio, TGs, and fasting insulin (standardized β varying −0.15 to −0.21) and positively related to HDL‐C and Si (standardized β 0.16 and 0.23). Age was not independently related to worsening of any blood lipid but was related to increased Si (standardized β for Si 0.25, insulin −0.31). With the exception of total cholesterol and LDL‐C, aerobic fitness was independently related to worsened blood lipid profile and increased Si (standardized β varying 0.17 to −0.21). Maintenance of favorable fat distribution and aerobic fitness may be important strategies for healthy aging, at least in premenopausal EA and AA women.

Maternal Glucose Concentration During Pregnancy Predicts Fat and Lean Mass of Prepubertal Offspring

OBJECTIVE Intrauterine exposure to high maternal glucose is associated with excess weight gain during childhood, but it is not clear whether the excess weight represents increased fat or lean mass. The purpose of this study was to examine the relationship between maternal glucose concentrations during pregnancy and offspring body composition. A secondary goal was to examine whether the association between maternal glucose and children’s body fat was independent of energy intake, energy expenditure, or physical activity. RESEARCH DESIGN AND METHODS Children aged 5–10 years and their biological mothers (n = 27) were recruited. Maternal glucose concentration 1 h after a 50-g oral glucose load, used to screen for gestational diabetes mellitus at 24–28 weeks gestation, was retrieved from medical records. Children underwent dual-energy X-ray absorptiometry to measure body composition, indirect calorimetry to measure resting energy expenditure (REE), accelerometry to measure physical activity, and three 24-h diet recalls to measure energy intake. RESULTS Maternal glucose concentration during pregnancy was positively associated with children’s lean mass (P < 0.05) and adiposity (fat mass adjusted for lean mass; P < 0.05). The association between maternal glucose and children’s adiposity was independent of children’s REE, percent of time spent physically active, and energy intake (P < 0.001). CONCLUSIONS Intrauterine exposure to relatively high maternal glucose is associated with greater lean mass and adiposity among prepubertal offspring. Further research is needed to examine the mechanisms by which maternal glucose concentrations during pregnancy influence children’s body composition.

Effects of diet macronutrient composition on body composition and fat distribution during weight maintenance and weight loss

Qualitative aspects of diet may affect body composition and propensity for weight gain or loss. We tested the hypothesis that consumption of a relatively low glycemic load (GL) diet would reduce total and visceral adipose tissue under both eucaloric and hypocaloric conditions.

Overweight status and intrauterine exposure to gestational diabetes are associated with children's metabolic health.

Offspring of women with gestational diabetes (OGD) have greater risk for obesity and impaired metabolic health. Whether impaired metabolic health occurs in the absence of obesity is not clear.

Body composition and endocrine status of long-term stress-induced binge-eating rats

Clinical binge eating runs a protracted course. The etiology of binge eating remains perplexing in part because, in humans, it is difficult to isolate and assess the independent and aggregate impact of various contributing variables. Using rats, we found that footshock stress and a history of caloric restriction (S+R), combine synergistically to induce binge eating. Stress and dieting are also strong antecedents and relapse factors in human eating disorders. Here we report further behavioral and physiological parallels to human binge eating. Like the protracted course of human binge eating, young female Sprague-Dawley rats continued to binge eat after 23 restriction/stress cycles (7 months) and this despite experiencing no significant weight loss during the restriction phases. Stress alone reduced adiposity by 35% (p<0.001) but S+R rats had no significant fat loss. An endocrine profile of normal plasma leptin and insulin levels but marked elevation of plasma corticosterone levels was found only in the binge-eating (S+R) rats (p<0.01), also paralleling endocrine profiles reported in clinical binge-eating studies. These behavioral and physiological similarities between this animal model and clinical binge eating increase its utility in understanding binge eating. Importantly, our findings also highlight the stubborn nature of binge eating: once a critical experience with dieting and stress is experienced, little if any further weight loss or food restriction is necessary to sustain it.

Gestational and early life influences on infant body composition at 1 year

Excess weight gain during both pre‐ and postnatal life increases risk for obesity in later life. Although a number of gestational and early life contributors to this effect have been identified, there is a dearth of research to examine whether gestational factors and weight gain velocity in infancy exert independent effects on subsequent body composition and fat distribution.

Favourable metabolic effects of a eucaloric lower‐carbohydrate diet in women with PCOS

Diet‐induced reduction in circulating insulin may be an attractive nonpharmacological treatment for women with polycystic ovary syndrome (PCOS) among whom elevated insulin may exacerbate symptoms by stimulating testosterone synthesis. This study was designed to determine whether a modest reduction in dietary carbohydrate (CHO) content affects β‐cell responsiveness, serum testosterone concentration and insulin sensitivity in women with PCOS.