Effects of intermittent fasting on body composition and clinical health markers in humans

Intermittent fasting is a broad term that encompasses a variety of programs that manipulate the timing of eating occasions by utilizing short-term fasts in order to improve body composition and overall health. This review examines studies conducted on intermittent fasting programs to determine if they are effective at improving body composition and clinical health markers associated with disease. Intermittent fasting protocols can be grouped into alternate-day fasting, whole-day fasting, and time-restricted feeding. Alternate-day fasting trials of 3 to 12 weeks in duration appear to be effective at reducing body weight (approximate to 3%-7%), body fat (approximate to 3-5.5 kg), total cholesterol (approximate to 10%-21%), and triglycerides (approximate to 14%-42%) in normal-weight, overweight, and obese humans. Whole-day fasting trials lasting 12 to 24 weeks also reduce body weight (approximate to 3%-9%) and body fat, and favorably improve blood lipids (approximate to 5%-20% reduction in total cholesterol and approximate to 17%-50% reduction in triglycerides). Research on time-restricted feeding is limited, and clear conclusions cannot be made at present. Future studies should examine long-term effects of intermittent fasting and the potential synergistic effects of combining intermittent fasting with exercise.