Time restriction of food consumption does not provide added benefit over calorie restriction alone

Reference

Liu D, Huang Y, Huang C, et al. Calorie restriction with or without time-restricted eating in weight loss. N Engl J Med 2022;386(16):1495-1504.

Synopsis

These researchers identified 139 obese adults aged 18 to 75 years with a body mass index (BMI) between 28 and 45. Persons with diabetes mellitus, vascular disease, and other serious comorbidities were excluded, as were tobacco users. At baseline, the mean BMI was 32 and the mean age was 32 years; half the participants were men. All participants were asked to restrict calories to 1500 to 1800 calories per day for men and 1200 to 1500 calories per day for women. This is about 75% of their pre-study intake. They were then randomly assigned to either consume those calories either only during a time window from 8 AM to 4 PM, or whenever they chose. All participants received extensive support throughout the one-year study, including twice-weekly calls or messages and biweekly meetings with a health coach for the first 6 months, with fewer meetings in the second 6 months. Adherence was 85% at one year. At one year, the time-restricted group lost a bit more weight (8.0 kg vs 6.3 kg), but this difference was not statistically or clinically significant. There were also no differences in secondary outcomes, such as cardiovascular risk factors or percentage of body fat. The fact that this study was done in China may limit generalization to other cultures.