Time-restricted eating, which limits food intake to specific daily hours, does not influence weight loss in overweight adults with prediabetes or diabetes. In a 12-week American Heart Association study, participants consumed identical healthy, pre-prepared meals. One group ate 80% of their calories before 1 p.m., while the other consumed 50% after 5 p.m.
"We've long wondered if the timing of meals affects how the body processes and stores energy," said lead author Nisa M. Maruthur, M.D., M.P.H., of Johns Hopkins University in Baltimore. "Prior studies often overlooked calorie intake, leaving uncertainty about whether earlier eaters simply consumed less. Here, we isolated timing as the only variable."
Maruthur and her team tracked 41 overweight adults, 90% of whom were Black women with prediabetes or diabetes (mean age: 59 years). Twenty-one followed time-restricted eating, consuming 80% of calories before 1 p.m. The other 20 ate over a standard 12-hour window, with half their calories after 5 p.m. All received the same study-provided meals. Weight and blood pressure were assessed at baseline, 4 weeks, 8 weeks, and 12 weeks.
Both groups achieved comparable weight loss and blood pressure reductions, irrespective of eating patterns.
"We anticipated greater weight loss in the time-restricted group," Maruthur noted. "Surprisingly, there was no difference based on when most calories were eaten, nor any impact on blood pressure."
The team is now analyzing 24-hour blood pressure data and combining it with findings from a related study on time-restricted eating's effects on blood sugar, insulin, and hormones.
"These insights will clarify time-restricted eating's role in cardiometabolic health," Maruthur added.
