Fasting May Not Be As Beneficial For Weight Loss As You Think

The act of fasting involves going an extended period of time without food (via WebMD). Some may choose to fast for half a day, while others may opt to refrain from eating for multiple consecutive days. Within the realm of fasting is a practice known as intermittent fasting. Rather than going for one long stretch without eating, intermittent fasting is structured in a way where periods of fasting are split up between bouts of eating, often on a daily or weekly basis (via Healthline). Examples include eating five days a week and then engaging in two days of fasting, or fasting for a period of 16 hours within a 24-hour period each day.

Within the category of intermittent fasting is another sub-category known as time-restricted eating, which involves eating only during times of day that coincide with our natural circadian rhythms (via Advances in Nutrition). Weight loss is purported to be a main benefit of fasting. However, new research published in the New England Journal of Medicine reveals that time-restricted eating may not aid weight loss as much as previously thought.

For one year, 139 patients with obesity followed a calorie-restricted diet. One group engaged in time-restricted eating (eating only between the hours of 8 a.m. and 4 p.m.) each day, while the other group was free to eat at any point throughout the day. 

During the course of the study, participants in both groups adhered to a calorie-restricted diet that consisted of 1,800 calories per day for men and 1,500 calories per day for women.

At the end of the study, researchers found that participants in both groups lost an average of 14 to 18 pounds, reports The New York Times. Not only did both methods provide similar weight loss results, but time-restricted eating did not appear to affect waist circumference, body fat, lean body mass, blood pressure, or blood glucose levels in patients any more than in those who ate their low-calorie diet freely throughout the day.

Researchers determined that ultimately, participant weight loss was attributed predominantly to reduced caloric intake and not the practice of time-restricted eating. Commenting on the study outcome, Director of Nutrition Studies at the Stanford Prevention Research Center Dr. Christopher Gardner states via The New York Times, " ... the take-home supported by this new research is that when subjected to a properly designed and conducted study ... [time-restricted eating] is not any more helpful than simply reducing daily calorie intake for weight loss and health factors."