Calorigenic response in obese and nonobese women

Abstract

The calorigenic response to a high protein test meal was studied in women with a history of childhood onset obesity. Obese and nonobese individuals were fasted overnight and basal oxygen consumptions determined the following morning. A semisynthetic 823 kcal high protein test meal was ingested within a 1-hr period followed by hourly determinations of oxygen consumption and plasma levels of insulin, free fatty acids, triglycerides, glucose, amino acids, and urea nitrogen. Amino acid levels increased faster and to a higher plateau in the nonobese group, while insulin levels increased and eventually decreased in a similar fashion in both groups. No differences in basal metabolic rate were detected. The postprandial increment in oxygen consumption was significantly less among the obese subjects. Diminished calorigenesis after each meal would result in accumulation of extra calories provided that caloric consumption is not appropriately decreased. These data suggest that a physiological aberration of energy metabolism may contribute to the development of childhood onset obesity.

Thermic effect of infused glucose and insulin in man. Decreased response with increased insulin resistance in obesity and noninsulin-dependent diabetes mellitus.

“…Although the quantitative thermogenic effect of physiologically liberated norepinephrine is not known, it is possible that the observed rise in norepinephrine contributed to part of the unexplained rise (35- (6)(7)(8)(9) or diabetic obese subjects (10) (40) and possibly a greater absolute inhibition of gluconeogenesis.…”

“…Recently, a reduced thermic effect of a meal in obese subjects, in comparison with that of normal weight subjects, has been reported, (6)(7)(8)(9)(10). It has been postulated that this decreased dietary-induced thermogenesis might be involved in the etiology of obesity or the maintenance of the obese state.…”

Thermic effect of food in lean and obese men.

“…The postprandial rise in caloric expenditure and its relationship to obesity have been the subject of intensive studies in the last decade. Numerous studies have shown that the thermic effect offood (TEF)' is blunted in obese subjects (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20). The authors of these reports claimed that because fewer nutrients were oxidized by obese humans, relatively more nutrients were stored by obese than lean people per caloric intake.…”

Brown Adipose Tissue in Man: A Review

“…Further, it should be possible to demonstrate that obese people have a reduced capacity for thermogenesis. Pittet et al (1976) found differences between lean and obese women in the size of response to a small meal (50 g glucose), but this was not confirmed by other workers (Kaplan & Leveille 1976, Clough & Durnin 1970. Blaza (1980) found no differences in the response of five lean and five obese women to a 1000 kcal (4.2 MJ) meal and moderate exercise although there were some differences in response to warm and cool environmental temperatures (all within 20-30"C and described by the subjects as 'comfortable').…”