ORIGINAL RESEARCH COMMUNICATION

Short-term modified alternate-day fasting: a novel dietary strategy for weight loss and cardioprotection in obese adults^1,2,3

Krista A Varady, Surabhi Bhutani, Emily C Church and Monica C Klempel

¹ From the Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, IL.

² Supported by departmental funding from the University of Illinois at Chicago.

³ Address correspondence and reprint requests to KA Varady, Kinesiology and Nutrition, University of Illinois at Chicago, 1919 West Taylor Street, Room 506F, Chicago, IL 60612. E-mail: varady@uic.edu .

Background: The ability of modified alternate-day fasting (ADF; ie, consuming 25% of energy needs on the fast day and ad libitum food intake on the following day) to facilitate weight loss and lower vascular disease risk in obese individuals remains unknown.

Objective: This study examined the effects of ADF that is administered under controlled compared with self-implemented conditions on body weight and coronary artery disease (CAD) risk indicators in obese adults.

Design: Sixteen obese subjects (12 women, 4 men) completed a 10-wk trial, which consisted of 3 phases: 1) a 2-wk control phase, 2) a 4-wk weight loss/ADF controlled food intake phase, and 3) a 4-wk weight loss/ADF self-selected food intake phase.

Results: Dietary adherence remained high throughout the controlled food intake phase (days adherent: 86%) and the self-selected food intake phase (days adherent: 89%). The rate of weight loss remained constant during controlled food intake (0.67 ± 0.1 kg/wk) and self-selected food intake phases (0.68 ± 0.1 kg/wk). Body weight decreased (P < 0.001) by 5.6 ± 1.0 kg (5.8 ± 1.1%) after 8 wk of diet. Percentage body fat decreased (P < 0.01) from 45 ± 2% to 42 ± 2%. Total cholesterol, LDL cholesterol, and triacylglycerol concentrations decreased (P < 0.01) by 21 ± 4%, 25 ± 10%, and 32 ± 6%, respectively, after 8 wk of ADF, whereas HDL cholesterol remained unchanged. Systolic blood pressure decreased (P < 0.05) from 124 ± 5 to 116 ± 3 mm Hg.

Conclusion: These findings suggest that ADF is a viable diet option to help obese individuals lose weight and decrease CAD risk. This trial was registered at clinicaltrials.gov as UIC-004-2009.