Total and resting energy expenditure in obese women reduced to ideal body weight.

Abstract

Obesity could be due to excess energy intake or decreased energy expenditure (EE). To evaluate this, we studied 18 obese females (148±8% of ideal body weight IIBW1, mean±SD) before and after achieving and stabilizing at IBW for at least 2 mo and a control group of 14 never obese females (< 110% of IBW or < 30% fat).In the obese, reduced obese, and never obese groups, the percent of body fat was 41±4%, 27±4%, and 25±3%; total energy expenditure (TEE) was 2704±449, 2473±495, and 2259±192 kcal/24 h; while resting metabolic rate was 1496±169, 1317±159, and 1341±103 kcal/24 h, respectively. 15 obese subjects who withdrew from the study had a mean initial body composition and EE similar to the subjects who were successful in achieving IBW. In 10 subjects followed for at least one year after stabilizing at IBW there was no significant relationship between the deviation from predicted TEE at IBW and weight regain.These studies indicate that, in a genetically heterogeneous female population, neither the propensity to become obese nor to maintain the obese state are due to an inherent metabolic abnormality characterized by a low EE. (J. Clin. Invest. 1993.

The effect of sibutramine on energy expenditure and appetite during chronic treatment without dietary restriction

“…27 Further, Amatruda et al found that changes in total EE during weight loss were better correlated with changes in body weight than with fatfree mass. 28 In this study sibutramine induced a weight loss above that of placebo by 2.6 kg and assuming that 75% of the weight loss consisted of fat this represents an energy content of 76,000 kJ. The increase in adjusted 24-h EE induced by sibutramine above placebo was 0.22 kJamin, or 17,700 kJ if extrapolated to the 8 week period.…”

Long - Term Effects of Energy-Restricted Diets Differing in Glycemic Load on Metabolic Adaptation and Body Composition*

“…Previous studies have reported both metabolic adaptation to weight loss [14][15][16][17] and no metabolic adaptation [19][20][21][22][23], and factors such as ongoing weight loss and lack of accounting for body fat change as well as FFM change may help explain the variability in results [26]. However, in our study, TEE was lower than expected based on the changes in fat and FFM (at 12 months of CR by approximately 0.76 MJ/d (180 kcals/d), equivalent to 6.6% of baseline TEE) suggesting an adaptive response to the long-term CR that may contribute to the recognized risk of weight regain following weight loss in mildly overweight individuals such as those studied here [58].…”

“…Metabolic adaptation can be defined as a change in energy expenditure with weight gain or loss over and above that accounted for by the change in body fat free mass (FFM) and fat mass, and may potentially impact long-term weight loss success. Some studies have reported that metabolic adaptation occurs during weight loss and/or subsequently [11][12][13][14][15][16][17][18] while others have found no evidence for this phenomenon [19][20][21][22][23][24][25]. In part, the different results obtained may be due to different mathematical approaches to calculating metabolic adaptation, as well as the duration and severity of caloric restriction (CR) [26].…”

Gender difference in the effect of body composition on energy metabolism

“…In fact, resting EE (REE) in obese and lean women was shown to be similar when adjusted for the differences in lean body mass and FM. 15 Moreover, it was demonstrated that post-obese and lean women displayed a similar REE, both in absolute terms 16 or adjusted for lean body mass. 17 Taken together, these results suggest that energy metabolism of men and women may not respond in the same manner to body weight reduction.…”