No difference in weight loss or metabolic markers with time-restricted eating
Effects of Time-Restricted Eating on Weight Loss and Other Metabolic Parameters in Women and Men With Overweight and Obesity - The TREAT Randomized Clinical Trial
Introduction and methods
Intermittent fasting is defined by eating windows and specified periods of fasting (>12 hours and up to 48 hours, or more). Intermittent fasting is getting more attention as a simple method for weight loss. However, this method is untested or undertested in humans . Time restricted eating (TRE) is a subtype of intermittent fasting and has consistent fasting and eating windows within a cycle of 24 hours.
Murine studies have shown beneficial effects of TRE [2,3] and small human studies suggested reduced calorie intake and decreased body weight and/or fat mass with TRE in individuals with overweight or obesity [4-8].
In this randomized clinical trial, the effect of TRE on weight and metabolic outcomes was examined in patients with overweight or obesity. 116 Patients were randomized to 8-hour TRE (16 hours fast:8 hours eat) or a standard 3-meals-per-day-diet (consistent meal timing, CMT) and were followed for 12 weeks. Participants were provided a Bluetooth weight scale, which was connected through a study app. The study interventions included recommendation to the timing of food intake (not for calorie intake or physical activity. 50 Study participants who lived close to San Francisco underwent extensive in-person metabolic testing. Participants had a mean age of 46.5 (SE: 10.5) years and mean weight was 99.2 (SD: 16.0) kg.
- There was a significant change in weight in the TRE group (-0.94 kg; 95%CI: -1.68 to -0.20 kg, P=0.01) and nonsignificant change in the CMT group (-0.68 kg; 95%CI: -1.41 to 0.05, P=0.07), with no difference in weight change between groups.
- In the in-person cohort of 50 participants, there was a significant change in weight in the TRE group (-1.70 kg, 95%CI: -2.56 to -0.83, P<0.001) but not in the CMT group (-0.57 kg, 95%CI: -1.40 to 0.26, P=0.18) with no difference between groups.
- There was a significant decrease in lean mass (calculated as fat-free mass minus bone mineral content) in the TRE group, but not in the CMT group, with no difference between the groups. For appendicular lean mass (ALM) there was a significant difference between the two groups.
- No differences between the two groups were observed for blood lipids, glucose, insulin and cardiometabolic markers.
No effect of TRE on weight loss was observed in a randomized trial of 116 patients when compared to a standard 3-meals-per-day-diet. Also, no differences were observed for metabolic markers between the two groups. The study showed a decrease in ALM in the TRE group, raising caution about the potential effect of TRE.