Background: The ability of modified alternate day fasting (ADF) (i.e. consuming 25% of energy needs on the fast day, and ad libitum fed on feed day) to facilitate weight loss and lower vascular disease risk in obese individuals remains unknown. Objective: This study examined the effects of ADF, administered under controlled versus self-implemented conditions, on body weight and coronary heart disease (CHD) risk indicators in obese adults. Design: Sixteen obese subjects (12 women/4 men) completed a 10-week trial, consisting of 3 phases: 1) 2-week control phase, 2) 4-week weight loss/ADF controlled feeding phase, and 3) 4-week weight loss/ADF self-selected feeding phase. Results: Dietary adherence remained high throughout the controlled feeding phase (86% days adherent), and the self-selected feeding phase (89% days adherent). Rate of weight loss remained constant during controlled feeding (0.67 ± 0.1 kg/week) and self-selected feeding phases (0.68 ± 0.1 kg/week). Body weight decreased (P < 0.001) by 5.6 ± 1.0 kg (5.8% ± 1.1%) after 8 weeks of diet. Percent body fat decreased (P < 0.01) from 45 ± 2% to 42 ± 2%. Total cholesterol, LDL cholesterol, and triacylglycerol concentrations were lowered (P < 0.01) by 21 ± 4%, 25 ± 10%, 32 ± 6%, respectively, after 8 weeks of ADF, while HDL cholesterol remained unchanged. Systolic blood pressure decreased (P < 0.05) from 124 ± 5 mm Hg to 116 ± 3 mm Hg. Conclusions: These findings suggest that ADF is a viable diet option to help obese individuals lose weight and decrease CHD risk.