Is the effect of time-restricted eating on cardiometabolic health simply due to caloric restriction? Original paper

In this randomized controlled trial in participants with obesity and impaired glycemic control, early time-restricted eating did not improve cardiometabolic risk factors compared to a calorie-matched usual eating pattern.

Whether time-restricted eating (TRE) promotes weight loss (the primary outcome) and improves cardiometabolic risk factors independent of caloric restriction.

The secondary outcomes were waist circumference, blood lipids, blood pressure, and measures of glycemic control, including fasting glucose, HOMA-IR, glucose tolerance (measured using a 2-hour oral glucose tolerance test), and glycated albumin (a measure of the average blood glucose level over 2–3 weeks similar to fructosamine).

41 participants (average age of 59; 93% women, 7% men; 93% Black) with obesity and prediabetes or diet-controlled type 2 diabetes who lived in the area of Baltimore, Maryland.

In this 12-week randomized controlled trial, the participants were assigned to TRE or a usual eating pattern (the control). In TRE, they were instructed to eat within a 10-hour window (from 8 a.m. to 6 p.m.) and to consume 80% of calories before 1 p.m. In the control, the eating window could be up to 16 hours and at least 50% of calories were to be consumed after 5 p.m.

The research staff provided the participants with all of the food they needed for the intervention period. The diets contained equal amounts of calories, macronutrients, and micronutrients. Dietary adherence was monitored via diaries, which were periodically reviewed by a registered dietitian. Physical activity was monitored using wrist-worn accelerometers at the beginning and end of the study.

There were no significant differences between groups.

Both groups lost a little over 2 kg (4.4 lbs) compared to baseline. Fasting glucose and HOMA-IR decreased in the TRE group only.