Alternate Day Fasting Combined with Exercise for Weight Loss and Cardio-Protection in Obese Adults

Objective: The effect of alternate day fasting (ADF) combined with endurance exercise (Ex) on body weight, body composition, coronary heart disease risks and behavioral factors has never been tested. Method: Obese subjects (n = 64) were randomized to 1 of 4 groups: 1) combination (ADF + endurance exercise), 2) ADF, 3) exercise, or 4) control, for 12 weeks. Results: Body weight was reduced (P < 0.05) by 6 ± 4 kg, 3 ± 1 kg, and 1 ± 0 kg in the combination, ADF, and exercise group, respectively. Fat mass decreased (P < 0.001) while lean mass was retained in the combination group. LDL cholesterol decreased (12 ± 5%, P < 0.05) and HDL cholesterol increased (18 ± 9%, P < 0.05) in the combination group only. LDL particle size increased (P < 0.001) in both the combination and ADF group, while small HDL particles decreased (P < 0.01) in the combination group only. FMD increased by 5% only in the ADF group. Leptin decreased in the combination (34 ± 9 ng/ml, P < 0.001), ADF (10 ± 4 ng/ml, P < 0.05) and exercise group (11 ± 4 ng/ml, P < 0.05). Changes in FMD in the ADF group were not related to changes in leptin. With behavioral factors, subjects chose to exercise the same amount (P = 0.790) on the fast days (48 ± 2%) as feed days (52 ± 2%). Likelihood to cheat on the fast day was not higher if the subject exercised in the afternoon (17 ± 7%) versus the morning (10 ± 5%). Hunger decreased (P < 0.05) while satisfaction and fullness increased (P < 0.05) post-treatment in the ADF group only. Restrained eating increased (P < 0.05) and uncontrolled eating decreased (P < 0.05) in the combination and ADF groups. Conclusions: These findings suggest that the combination produces superior changes in body weight, body composition, and plasma lipids, when compared to individual treatments. ADF alone is an effective intervention to improve endothelial function. This combination therapy also leads to positive behavioral changes that may contribute to long-term steady weight loss.