Energy expenditure and everyday eating behavior in healthy young women.

The doubly labeled water method was used to measure average daily total energy expenditure (EE) in 23 healthy normal-weight women classified as restrained or unrestrained eaters. Although the relative weight of restrained eaters was found to be higher (BMI 21.1 +/- 1.3 vs 20.0 +/- 1.3 kg/m2, p less than 0.03), the self-reported energy consumption of the restrained eaters, when adjusted for body composition and height, totaled approximately 410 kcal/d less energy than that of the unrestrained group (p less than 0.002). Correspondingly, the adjusted EE was found to be lower by 620 kcal/d in restrained eaters (p less than 0.005). In both groups metabolic indices of starvation (beta-hydroxybutyric acid and triiodothyronine) were in the normal range. Neither these nor weight changed from the beginning to the end of the 14-d observation period. Thus, the lower EE of the restrained group reflects diminished caloric requirements and is not an adaptive response to a temporary decrease in food intake.