Effects of energy restriction on acute adrenoceptor and metabolic responses to exercise in obese subjects

Effects of energy restriction on acute adrenoceptor and metabolic responses to exercise in obese subjects. Kempen KP, Saris WH, Senden JM, Menheere PP, Blaak EE, van Baak MA. Department of Human Biology, University of Limburg, Maastricht, The Netherlands. This study was intended to investigate the effects of energy restriction on the acute responses of platelet alpha 2- and lymphocyte beta 2-adrenoceptors to exercise in obese female subjects. Seven obese females were restricted to a low-energy formula diet (2.0 MJ/day) for 4 wk. As result of the diet, there was a 7.8-kg weight loss. No significant changes could be detected in sleeping and resting metabolic rate expressed per kilogram fat-free mass. Basal venous glucose, insulin, and norepinephrine levels decreased as a result of the diet, whereas free fatty acid values increased. Before the diet, 60 min of exercise (45% peak mechanical power) caused no alteration in the density of lymphocyte beta 2-adrenoceptors. At the end of 4 wk of dieting, the density was significantly increased in response to exercise, together with a higher thermogenic and lipolytic response and decreased venous insulin levels. Energy restriction resulted in an increased basal platelet alpha 2-adrenoceptor density, whereas exercise did not modify density and affinity of platelet alpha 2-adrenoceptors. The results indicate that adrenoceptor numbers can be modulated by energy restriction in obesity. Modulation of adrenoceptor density may play a role in increased exercise-induced lipolysis during energy restrictio

Determinants of weight maintenance in women after diet-induced weight reduction.

Open University, Heerlen, The Netherlands. OBJECTIVE: Assessment of determinants for relatively successful weight maintenance in women after diet-induced weight reduction. DESIGN: Subjects followed two weight cycles over two years, each cycle starting with a Very Low Energy Diet (VLED) (2.8 MJ/d), in a free-living situation. They completed the Herman Polivy Restraint Questionnaire and the Three Factor Eating Questionnaire twice, that is, before and during the first VLED. SUBJECTS: Twenty seven obese women, body mass index (BMI) (28-38 kg/m2), age (19-53 y), being premenopausal and healthy, participated twice in the energy restriction periods with one year follow-up. MEASUREMENTS: Weight and body composition were measured at weeks 0, 8, 60, 68 and 120 after the start of the first VLED. Scores on the restraint scales before and during the first VLED were analysed. Percentages regain after one year and after two years follow-up were related to these scores. RESULTS: Three groups appeared with respect to success regarding weight maintenance. Group 1 (successful): twice a regain 50% of weight loss. Percentage regain was negatively correlated to an increase in cognitive restrained eating behaviour (r = 0.8; P = 0.0001). A change in attitude with respect to food intake, expressed as an increase in cognitive restraint, and as a positive relationship between cognitive restraint and disinhibition was related to successful weight maintenance. CONCLUSION: An increase in cognitive restraint from before, to during, the diet, and a positive correlation between cognitive restraint and disinhibition, are two determinants representing eating behaviour for successful weight maintenance