Marta Garaulet, Francisca Perez-Llamas, Millan Perez-Ayala, Pedro Martinez, Fermin Sanchez de Medina, Francisco J Tebar, Salvador Zamora
Nov 1, 2001; 74:585-591
Lipids
November 1, 2001
February 7, 2012
[Cardiovascular disease risk] Effect of exercise intensity on abdominal fat loss during calorie restriction in overweight and obese postmenopausal women: a randomized, controlled trial
Background: Exercise intensity may affect the selective loss of abdominal adipose tissue.
Objective: This study showed whether aerobic exercise intensity affects the loss of abdominal fat and improvement in cardiovascular disease risk factors under conditions of equal energy deficit in women with abdominal obesity.
Design: This was a randomized trial in 112 overweight and obese [body mass index (in kg/m2): 25–40; waist circumference >88 cm], postmenopausal women assigned to one of three 20-wk interventions of equal energy deficit: calorie restriction (CR only), CR plus moderate-intensity aerobic exercise (CR + moderate-intensity), or CR plus vigorous-intensity exercise (CR + vigorous-intensity). The diet was a controlled program of underfeeding during which meals were provided at individual calorie levels (400 kcal/d). Exercise (3 d/wk) involved treadmill walking at an intensity of 45–50% (moderate-intensity) or 70–75% (vigorous-intensity) of heart rate reserve. The primary outcome was abdominal visceral fat volume.
Results: Average weight loss for the 95 women who completed the study was 12.1 kg (±4.5 kg) and was not significantly different across groups. Maximal oxygen uptake (
Conclusion: With a similar amount of total weight loss, lean mass is preserved, but there is not a preferential loss of abdominal fat when either moderate- or vigorous-intensity aerobic exercise is performed during caloric restriction. This trial was registered at clinicaltrials.gov as NCT00664729.
[Immunity] Fasting and postprandial markers of inflammation in lean and overweight children
Background: Overweight children have greater circulating concentrations of markers of inflammation (MOI) than do lean children. Whether adiposity influences the postprandial MOI response is unknown.
Objective: We aimed to evaluate the relations of fasting and postprandial MOI with total and regional adiposity and insulin sensitivity in children.
Design: Fifty-nine children aged 7–12 y were assessed for C-reactive protein (CRP), interleukin-6 (IL-6), and soluble tumor necrosis factor receptor-2 (sTNF-R2) in the fasted state and after a mixed meal. Insulin sensitivity, body composition, and abdominal adipose tissue distribution were assessed with a frequently sampled intravenous-glucose-tolerance test, dual-energy X-ray absorptiometry, and computed tomography, respectively.
Results: Central adipose measures were not independently associated with fasting MOI, although they were independently inversely associated with the postprandial sTNF-R2 response (r = –0.30 to –0.37, P = 0.02–0.006). The inverse association between intraabdominal adipose tissue and the postprandial CRP response was nearly significant (r = –0.27, P = 0.05). Insulin sensitivity was not associated with fasting or postprandial CRP or sTNF-R2; however, there was a positive relation between insulin sensitivity and fasting IL-6 (r = 0.27, P = 0.03), which was attenuated after adjustment for lean body mass (r = 0.25, P = 0.08).
Conclusions: Excess adiposity is associated with both fasting and postprandial MOI. The postprandial MOI response may be influenced by central adiposity in children. The positive association of insulin sensitivity with IL-6 warrants further study.
Adiposity and human regional body temperature [Obesity and eating disorders]
Background: Human obesity is associated with increased heat production; however, subcutaneous adipose tissue provides an insulating layer that impedes heat loss. To maintain normothermia, therefore, obese individuals must increase their heat dissipation.
Objective: The objective was to test the hypothesis that temperature in a heat-dissipating region of the hand is elevated in obese adults.
Design: Obese [body mass index (in kg/m2) ≥ 30] and normal-weight (NW; body mass index = 18–25) adults were studied under thermoneutral conditions at rest. Core body temperature was measured by using ingested telemetric capsules. The temperatures of the third fingernail bed of the right hand and of abdominal skin from an area 1.5 cm inferior to the umbilicus were determined by using infrared thermography. Abdominal skin temperatures were also measured via adhesive thermistors that were placed over a prominent skin-surface blood vessel and over an adjacent nonvessel location. The groups were compared by analysis of covariance with age, sex, race, and room temperature as covariates.
Results: Core temperature did not differ significantly between the 23 obese and 13 NW participants (P = 0.74). However, infrared thermography–measured fingernail-bed temperature was significantly higher in obese subjects than in NW subjects (33.9 ± 0.7°C compared with 28.6 ± 0.9°C; P < 0.001). Conversely, infrared thermography–measured abdominal skin temperature was significantly lower in obese subjects than in NW subjects (31.8 ± 0.2°C compared with 32.8 ± 0.3°C; P = 0.02). Nonvessel abdominal skin temperatures measured by thermistors were also lower in obese subjects (P = 0.04).
Conclusions: Greater subcutaneous abdominal adipose tissue in obese adults may provide a significant insulating layer that blunts abdominal heat transfer. Augmented heat release from the hands may offset heat retention in areas of the body with greater adiposity, thereby helping to maintain normothermia in obesity. This trial was registered at clinicaltrials.gov as NCT00266500.
An integrative view of obesity [Supplement: An Integrative View of Obesity]
Obesity is the result of the accumulation of excess body fat and not simply excess weight that can be muscle or fat. Adipocytes function in the adaptation to starvation, in exercise energetics, and in the immune defense against pathogens. Sustained positive energy balance results in excessive accumulation of adipocytes, which, in the abdomen, leads to chronic inflammation. Although informative studies have been performed with cultured adipocytes, an integrative approach to the regulation of abdominal adipose tissue involves feedback from autocrine and paracrine effectors secreted by adipocytes, the immune system, and blood flow through adipose tissue. Numerous adipokines, chemokines, and cytokines feed back to other bodily systems to regulate both energy balance and immune function. Studies of the interactions of the gastrointestinal tract and the central nervous system, as well as psychophysiological considerations of reward circuitry in the central nervous system, have shown a general adaptation to starvation that is opposed to those strategies being proposed for the prevention and treatment of obesity, ie, food restriction and increased physical activity. The obesogenic environment of highly palatable foods with hidden fats and sugars can promote metabolic syndrome and obesity, whereas fruit and vegetables with antiinflammatory phytochemicals can counteract metabolic syndrome. Therefore, a plant-based diet and the seamless integration of increased physical activity and social support to alter modern diets and lifestyles hold out the greatest hope for the solution of the obesity epidemic. Both public health and medical nutrition approaches can benefit from this integrative view of obesity.