Alternate day fasting for weight loss in normal weight and overweight subjects: a randomized controlled trial

Background: Alternate day fasting (ADF; ad libitum "feed day", alternated with 25% energy intake "fast day"), is effective for weight loss and cardio-protection in obese individuals. Whether these effects occur in normal weight and overweight individuals remains unknown. This study examined the effect of ADF on body weight and coronary heart disease risk in non-obese subjects. Methods: Thirty-two subjects (BMI 20-29.9 kg/m(2)) were randomized to either an ADF group or a control group for 12 weeks. Results: Body weight decreased (P < 0.001) by 5.2 +/- 0.9 kg (6.5 +/- 1.0%) in the ADF group, relative to the control group, by week 12. Fat mass was reduced (P < 0.001) by 3.6 +/- 0.7 kg, and fat free mass did not change, versus controls. Triacylglycerol concentrations decreased (20 +/- 8%, P < 0.05) and LDL particle size increased (4 +/- 1 angstrom, P < 0.01) in the ADF group relative to controls. CRP decreased (13 +/- 17%, P < 0.05) in the ADF group relative to controls at week 12. Plasma adiponectin increased (6 +/- 10%, P < 0.01) while leptin decreased (40 +/- 7%, P < 0.05) in the ADF group versus controls by the end of the study. LDL cholesterol, HDL cholesterol, homocysteine and resistin concentrations remained unchanged after 12 weeks of treatment. Conclusion: These findings suggest that ADF is effective for weight loss and cardio-protection in normal weight and overweight adults, though further research implementing larger sample sizes is required before solid conclusion can be reached.