TY - JOUR
T1 - A rapidly occurring compensatory decrease in physical activity counteracts diet-induced weight loss in female monkeys
AU - Sullivan, Elinor L.
AU - Cameron, Judy L.
PY - 2010/4
Y1 - 2010/4
N2 - To study changes in energy balance occurring during the initial phases of dieting, 18 adult ovariectomized female monkeys were placed on a low-fat diet, and available calories were reduced by 30% compared with baseline consumption for 1 mo. Surprisingly, there was not significant weight loss; however, daily activity level (measured by accelerometry) decreased soon after diet initiation and reached statistical significance by the 4th wk of dieting (18 ± 5.6% decrease, P = 0.02). During a 2nd mo of dieting, available calories were reduced by 60% compared with baseline consumption, leading to 6.4 ± 1.7% weight loss and further suppression of activity. Metabolic rate decreased by 68 ± 12 kcal/day, with decreased activity accounting for 41 ± 9 kcal/day, and the metabolic activity of the weight lost accounting for 21 ± 5 kcal/day. A second group of three monkeys was trained to run on a treadmill for 1 h/day, 5 days/wk, at 80% maximal capacity, leading to increased calorie expenditure of 69.6 ± 10.7 kcal/day (equivalent to 49 kcal/day for 7 days). We conclude that a diet-induced decrease in physical activity is the primary mechanism the body uses to defend against diet-induced weight loss, and undertaking a level of exercise that is recommended to counteract weight gain and promote weight loss is able to prevent the compensatory decrease in physical activity-associated energy expenditure that slows diet-induced weight loss.
AB - To study changes in energy balance occurring during the initial phases of dieting, 18 adult ovariectomized female monkeys were placed on a low-fat diet, and available calories were reduced by 30% compared with baseline consumption for 1 mo. Surprisingly, there was not significant weight loss; however, daily activity level (measured by accelerometry) decreased soon after diet initiation and reached statistical significance by the 4th wk of dieting (18 ± 5.6% decrease, P = 0.02). During a 2nd mo of dieting, available calories were reduced by 60% compared with baseline consumption, leading to 6.4 ± 1.7% weight loss and further suppression of activity. Metabolic rate decreased by 68 ± 12 kcal/day, with decreased activity accounting for 41 ± 9 kcal/day, and the metabolic activity of the weight lost accounting for 21 ± 5 kcal/day. A second group of three monkeys was trained to run on a treadmill for 1 h/day, 5 days/wk, at 80% maximal capacity, leading to increased calorie expenditure of 69.6 ± 10.7 kcal/day (equivalent to 49 kcal/day for 7 days). We conclude that a diet-induced decrease in physical activity is the primary mechanism the body uses to defend against diet-induced weight loss, and undertaking a level of exercise that is recommended to counteract weight gain and promote weight loss is able to prevent the compensatory decrease in physical activity-associated energy expenditure that slows diet-induced weight loss.
KW - Activity
KW - Calorie reduction
KW - Obesity
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U2 - 10.1152/ajpregu.00617.2009
DO - 10.1152/ajpregu.00617.2009
M3 - Article
C2 - 20071608
AN - SCOPUS:77949831819
SN - 0363-6119
VL - 298
SP - R1068-R1074
JO - American Journal of Physiology - Regulatory Integrative and Comparative Physiology
JF - American Journal of Physiology - Regulatory Integrative and Comparative Physiology
IS - 4
ER -