All forms of fasting reviewed produced mild to moderate weight loss, 1%-8% from baseline weight, according to the analysis published in the Annual Review of Nutrition.
This represents results that are similar to that of more traditional, calorie-restrictive diets, it said.
Intermittent fasting regimens may also benefit health by decreasing blood pressure and insulin resistance, and in some cases, cholesterol and triglyceride levels are also lowered. Other health benefits, such as improved appetite regulation and positive changes in the gut microbiome, have also been demonstrated, the review claimed.
The review looked at over 25 research studies involving three types of intermittent fasting:
- Alternate day fasting, which typically involves a feast day alternated with a fast day where 500 calories are consumed in one meal.
- 5:2 diet, a modified version of alternate day fasting that involves five feast days and two fast days per week.
- Time-restricted eating, which confines eating to a specified number of hours per day, usually four to 10 hours, with no calorie restrictions during the eating period.
Various studies of time-restricted eating show participants with obesity losing an average of 3% of their body weight, regardless of the time of the eating window.
Studies showed alternate day fasting resulted in weight loss of 3%-8% of body weight over three to eight weeks, with results peaking at 12 weeks. Individuals on alternate day fasting typically do not overeat or binge on feast days, which results in mild to moderate weight loss, according to the review.
Studies for the 5:2 diet showed similar results to alternate day fasting, which surprised the study’s reviewers. The subjects who participate in the 5:2 diet fast much less frequently than alternate-day fasting participants do, but the results of weight loss results are similar.
Weight loss in both the alternate day and 5:2 fasting are comparable to more traditional daily calorie-restrictive diets. And, both fasting diets showed individuals were able to maintain an average of 7% weight loss for a year.
“We noted that intermittent fasting is not better than regular dieting; both produce the same amount of weight loss and similar changes in blood pressure, cholesterol and inflammation,” said Krista Varady, professor of nutrition at the UIC College of Applied Health Sciences and author of Cardiometabolic Benefits of Intermittent Fasting, adding: “You’re fooling your body into eating a little bit less and that’s why people are losing weight.”
Varady said the review set out to debunk some myths regarding intermittent fasting. Intermittent fasting does not …….