DAILY EXERCISE ENHANCES FAT UTILIZATION AND MAINTAINS METABOLIC RATE DURING SEVERE ENERGY RESTRICTION IN HUMANS

Abstract

Whether daily exercise initiated with dieting can increase resting energy expenditure and fat utlization while minimizing loss of lean tissue is equivocal. Therefore, the effect of a 4‐week program of food restriction and daily exercise on resting metabolic rate (RMR) and body composition was studied and compared with the effect of the same diet program without exercise on moderately obese humans. Following a 7‐day control period, 13 subjects consumed a diet providing 600 Kcal/day (2510 kJ/day) for 4 weeks; eight subjects exercised 30 to 45 minutes daily at 60 to 65% maximum oxygen uptake (DE group) and five subjects remained sedentary throughout the study (D group). RMR was measured by indirect calorimetry between 5 and 8 AM each morning after an overnight fast and a weekly average was calculated for each subject. Body composition was determined by hydrodensitom‐etry each week. RMR decreased significantly, amounting to 88% of the predietary control after 4 weeks of dieting in the D group. In contrast, RM...