Diabetes patients lost more weight with time-restricted eating than calorie counting

Over the course of six months, eating only between noon and 8 p.m. had a greater impact on weight loss and a similar effect on HbA1c levels compared with reducing energy intake by 25%, according to a small randomized trial of patients with type 2 diabetes and obesity.

Following a time-restricted eating strategy without calorie counting was more effective than daily calorie counting alone for weight loss among patients with type 2 diabetes, new trial results show.

Researchers randomized 75 participants with type 2 diabetes to an eight-hour time-restricted eating regimen (eating from noon to 8 p.m. only), to a calorie restriction strategy (25% energy restriction daily), or to a control group. Participants had a mean age of 55 years and a baseline average body mass index of 39 kg/m2. The majority (71%) of participants were women, and 53% were non-Hispanic Black. Findings were published by JAMA Network Open on Oct. 27.

At six months, time-restricted eating participants lost significantly more of their body weight than controls (−3.56% [95% CI, −5.92% to −1.20%]; P=0.004), while those on calorie restriction had an insignificant decrease (−1.78% [95% CI, −3.67% to 0.11%]; P=0.06). HbA1c levels decreased in both intervention groups compared with controls, with no significant differences between the two arms (−0.91% [95% CI, −1.61% to −0.20%] and −0.94% [95% CI, −1.59% to −0.30%], respectively).

Participants in the time-restricted eating group were adherent to their regimen for 6.1 days per week, on average, according to patients' daily logs. Sixty-eight percent of patients in the calorie restriction group were adherent with their calorie goals over the study window. Average reductions in energy intake were −313 kcal/d for the time-restricted eating group, compared with −197 kcal/d in the calorie restriction group. Controls had an average reduction of −16 kcal/d.

Participants in the time-restricted eating group also reported their intervention was easier to adhere to compared with participants who restricted calorie intake. No differences in time in euglycemic range, medication effect score, blood pressure, and plasma lipid levels were seen between groups, and no serious adverse events took place.

One limitation to the study is that researchers relied on self-reported dietary intake. “Since individuals with obesity tend to underreport energy consumption by 15% to 20%, it is likely that our estimates of energy intake are inaccurate,” they wrote. The authors also mentioned that for patients on a sulfonylurea or insulin, time-restricted eating may necessitate medication changes and closer monitoring.

Overall, “time-restricted eating is an appealing approach to weight loss in that it can be adopted at no cost, allows patients to continue consuming familiar foods, and does not require complicated calorie counting,” the authors said. Additional randomized controlled trials with longer follow-up are needed to confirm the findings, they concluded.