Around one in ten people is diagnosed with diabetes and most of these folks have type 2 diabetes. Maintaining a healthy weight when you have this condition is an important goal. But until now, it hasn’t been clear which diet plan is most likely to succeed.

A new University of Chicago study may have found the answer. The key to success, the researchers discovered, is to pay attention to when you eat and eat only between noon and 8 p.m.

This type of dieting is known as intermittent fasting or time-restricted eating.

Although intermittent fasting eating can be beneficial, there may also be side-effects or risks, especially for those with diabetes.

The study, which took place over six months, included a group of 75 racially and ethnically diverse people between 18 to 80 years old dealing with obesity and type 2 diabetes. Participants were placed into one of three groups:

  • A time-restricted group who could only eat between noon and 8 pm.
  • A calorie-restricted group who could eat any time of day but counted their calories using the MyFitnessPal mobile app. Their goal was to reduce their caloric intake by 25 percent of their maintenance calories — the calories needed to maintain their current weight.
  • A control group who continued eating their normal diet.

The research team found that the folks on the time-restricted eating diet lost over 3.5 percent of their body weight when compared to the control group, the equivalent of a 275-pound person losing just under 10 pounds. The calorie restriction group did not lose any weight compared to the control group.

“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,” Vicky Pavlou, RD, a doctoral student at the University of Illinois at Chicago who performed the new research, said in a press release. “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.”

For some, watching the clock instead of counting calories is a simpler way to lose weight.

Although intermittent fasting can be beneficial, there may also be side-effects or risks, especially for folks with diabetes. For example, intermittent fasting might cause hypoglycemia (low blood sugar) or hyperglycemia (too much blood sugar, or glucose, in the blood) which can occur if you take diabetes medication and do not eat enough food during the eating window. That’s because certain diabetic drugs require food for absorption and won’t absorb if you’re fasting. Also, certain diabetic drugs lower the blood sugar rapidly and fasting can put you at risk of low blood sugar levels — which can be life-threatening.

“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 says. But she also agrees that it’s important to be cautious. “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.”

What’s the take-away? If you have type 2 diabetes, consider using an intermittent fasting approach to lose weight, but work closely with your doctor or dietitian.

This study was presented on Monday July 24 at the NUTRITION 2023, the annual flagship meeting of the American Society of Nutrition July 22-25 in Boston.