Intermittent fasting — a diet that reportedly helped stars including Jennifer Aniston, Kourtney Kardashian, and Chris Pratt shed unwanted pounds, according to People — has been transcending its status as a celebrity fad as research about its weight loss and other benefits continues to emerge. The latest, a review published in October 2021 in Annual Review of Nutrition found that intermittent fasting leads to roughly the same amount of weight loss as traditional calorie-restrictive diets, and may improve other markers of cardiometabolic health as well.
“One of our main findings was that people who do intermittent fasting lose about the same amount of weight as people on a regular calorie-restriction diet that cuts out 500 calories a day,” says lead author Krista Varady, PhD, researcher and professor of nutrition at the University of Illinois, Chicago.
Additionally, Dr. Varady notes that intermittent fasting appears to help with metabolic health. “It did help lower blood pressure,” she says. “Some studies reported decreases in LDL [bad] cholesterol and triglycerides, and insulin resistance.”
What Is an Intermittent Fasting Diet?
In general, intermittent fasting (IF) refers to any eating schedule that alternates periods of going without food (fasting) with meals. There are many different types of plans, including those that restrict calories for only certain hours of each day or certain days of the week. The main difference between IF and traditional calorie-restriction diets is that IF doesn’t limit portions or foods, only when you eat them.
The review, which included more than 25 studies that looked at intermittent fasting in humans, found that IF consistently resulted in people consuming fewer total calories — between 10 and 30 percent fewer than they had been eating at the onset of the studies — which led to weight loss.
The review also included safety considerations and practical advice for how these diets should be implemented in everyday life.
RELATED: 7 Essential Facts About Your Metabolism and Weight Loss
What Types of Intermittent Fasting Plans Lead to Weight Loss?
The review included studies on three types of intermittent fasting:
- Alternate day fasting (ADF), which typically involves a day of unrestricted eating alternated with a fasting day where 500 calories consumed in one meal account for the total daily calorie intake
- The 5:2 diet, a modified version of alternate day fasting that involves five “feasting days” and two fasting days per week.
- Time-restricted eating (TRE), which limits eating to a specified number of hours per day (most often 8, but plans range …….