• Posted July 24, 2023

Timed Fasting Best Way for Those With Diabetes to Lose Weight

Restricting eating to certain times -- a regimen known as intermittent fasting -- may be the best way to help people with type 2 diabetes lose weight.

Researchers found that people with type 2 diabetes who ate only between noon and 8 p.m. lost more daily weight than those who counted calories.

Both strategies resulted in similar improvements to participants' blood sugar levels.

The findings will be presented Monday at a meeting of the American Society for Nutrition, in Boston.

“Many people find counting calories very hard to stick to in the long term, but our study shows that watching the clock may offer a simple way to decrease calories and lose weight,” said researcher and study presenter Vicky Pavlou, a doctoral student at the University of Illinois at Chicago.

“Although time-restricted eating is becoming increasingly popular, no other studies have looked at an eight-hour eating window in people with type 2 diabetes," she said in a meeting news release.

The eight-hour window had been previously studied in people with obesity. Type 2 diabetes is a metabolic disorder that is strongly associated with being overweight or obese.

For this study, a team led by Krista Varady, a professor of nutrition at UIC, studied a group of 75 racially and ethnically diverse people who had obesity and type 2 diabetes. They ranged in age from 18 to 80.

Participants were placed into one of three groups: time-restricted eating, calorie restriction and control.

Those in the time-restricted group ate only between noon and 8 p.m. The calorie-restriction group could eat at any time of the day; they used a mobile app to count their calories. Their objective was to reduce calorie intake by 25% from the level needed to maintain their current weight. The control group ate their normal diet.

Compared to the control group, people on the time-restricted eating diet lost 3.55% of their body weight over six months while the calorie restriction group lost none.

Compared to the control group, blood sugar (HbA1C) levels dropped in both the time-restricted group (-0.91%) and the calorie restriction group (-0.95%).

The weight loss achieved by those who did lose weight did not reach the 5% mark typically necessary for improvement in cardiometabolic risk factors, researchers said. Participants were taking cholesterol and blood pressure medications, which can make it hard to improve these risk factors.

“Our study shows that time-restricted eating can be a good alternative for those with type 2 diabetes who want to lose weight and improve their blood sugar,” Pavlou said. “However, there are multiple types of medications for those with type 2 diabetes, some of which can cause low blood sugar and some that need to be taken with food. Therefore, it is important to work closely with a dietitian or doctor when implementing this dieting approach.”

Findings presented at medical meetings are considered preliminary until published in a peer-reviewed journal.

More information

The U.S. National Institute on Aging has more on intermittent fasting.

SOURCE: American Society for Nutrition, news release, July 24, 2023