MEAL-INDUCED THERMOGENESIS IN PREVIOUSLY OBESE PATIENTS

Summary. Meal‐induced thermogenesis is reported to be reduced in obese patients and the purpose of this study was to find out whether thermogenesis after a mixed meal differs between previously obese(post‐obese) subjects and non‐obese controls. Nine post‐obese patients (body mass index 27 ±1) and nine age‐ and sex‐matched non‐obese volunteers (body mass index 22 ±1) were studied with continuous indirect calorimetry in the basal state and after the ingestion of a standardized test meal. Following treatment with vertical banded gastroplasty for the obesity, the weight of the patients had decreased by an average of 44 ± 5 kg. Basal oxygen uptake and energy expenditure did not differ between the post‐obese and the controls. After the meal, energy expenditure increased rapidly, becoming relatively constant after 60 min; the average increase above basal was in the post‐obese 30·5 ± 1·8% and in the non‐obese controls 29·5 ±2·3% (NS). In absolute terms, the increments above basal were also similar in the two groups. The heart rate was higher in the post‐obese group throughout the study period. It is concluded that the thermogenic response to a mixed meal is much the same in post‐obese subjects and in non‐obese controls. These findings support the notion that a decreased meal‐induced thermogenesis is a secondary phenomenon rather than a primary pathogenic factor in human obesity. Copyright © 1990, Wiley Blackwell. All rights reserved