Time restricted eating not more beneficial than daily calorie restriction

1. For patients with obesity, time-restricted eating was not more significantly beneficial in reducing body weight or body fat than daily calorie restriction.

2. For patients with obesity, time-restricted eating was not more beneficial in reducing metabolic risk factors than daily calorie restriction.

Evidence Rating Level: 1 (Excellent)

Study Rundown: Weight loss via lifestyle modification is the cornerstone of weight management, especially in patients with obesity. Daily calorie restriction is already a well-established primary weight-loss strategy, though long-term maintenance of weight loss remains a challenge. Time-restricted eating has been proposed as a new weight-loss strategy because it is easy to follow, which can enhance adherence. It consists of intermittent fasting that involves a shortened period for eating within each 24-hour period. However, there is a gap in knowledge as to understanding the long-term efficacy and safety of time-restricted eating compared to daily calorie restriction alone. This study found that time-restricted eating, when compared to daily calorie restriction, had similar success in patients regarding their weight loss. This study was limited by limited generalizability to patients with diabetes or cardiovascular disease, to different periods of time-restricted eating, and not assessing total energy expenditure. Nevertheless, these study’s findings are significant, as they demonstrate that time-restricted eating is not more beneficial with regards to weight loss or reduction in metabolic risk factors than daily calorie restriction alone.

Click to read the study in NEJM

Relevant Reading: Calorie and Time Restriction in Weight Loss

In-Depth [randomized clinical trial]: This randomized clinical trial consisted of participants from Guangzhou, China, and randomly assigned either a time-restricted eating regimen or a daily calorie restriction regimen for 12 months. Patients who were between 18 and 75 years of age, and had a BMI between 28 and 45 were eligible for the study. Patients with acute or chronic viral hepatitis, malignant tumors, diabetes, serious liver dysfunction or chronic kidney disease, current smoking, serious cardiovascular disease, severe gastrointestinal disease, active participation in a weight-loss program, or current or planned pregnancy were excluded from the study. The primary outcome measured was the difference between the two groups in the change from baseline in body weight at 12 months. Outcomes in the primary analysis were assessed via the intention-to-treat principle using a mixed-effects model with an autoregressive correlation matrix and subsequent subgroup analyses. Based on the analysis, of the 139 participants who underwent randomization, 118 completed the 12-month follow-up visit. In the time-restricted group, the mean weight loss from baseline at 12 months was -8.0kg (95% Confidence Interval [CI], -9.6 to -6.4), and -6.3kg (95% CI, -7.8 to -4.7) in the daily calorie restriction group. The change in weight was not significantly different in the two groups at the 12-month follow-up (net difference, -1.8kg; 95% CI, -4.0 to 0.4). Secondary analyses of the waist circumferences, BMI, body fat, body lean mass, blood pressure, and metabolic risk factors were consistent with the results of the primary outcome, and there were no significant differences observed. Overall, this study demonstrates that time-restricted eating was not more beneficial in the reduction of body weight, body fat, or metabolic risk factors when compared to daily calorie restriction alone in patients with obesity.

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