Calorie Restriction with or without Time-Restricted Eating in Weight Loss.
AI Summary
This 12-month randomized controlled trial examined whether time-restricted eating (8 AM-4 PM) combined with calorie restriction offers additional weight loss benefits compared to daily calorie restriction alone. The study assigned 139 patients with obesity to either time-restricted eating with calorie restriction (1200-1800 calories daily based on sex) or calorie restriction alone. The researchers found that time-restricted eating did not provide superior weight loss outcomes compared to standard calorie restriction. Both groups achieved meaningful weight loss, but the difference between approaches was not statistically significant. The study suggests that for individuals following the Blueprint Nutrition Protocol, the timing of food intake may be less critical than maintaining appropriate caloric intake for weight management. These findings indicate that while time-restricted eating can be an effective tool, it may not offer additional metabolic advantages beyond calorie control alone for weight loss in people with obesity.
Key Findings
- Time-restricted eating group lost an average of 8.0 kg while daily calorie restriction group lost 6.3 kg over 12 months, with no statistically significant difference between groups
- Both approaches showed similar improvements in waist circumference, BMI, body fat, and metabolic risk factors
- 84.9% of participants completed the 12-month study with no substantial differences in adverse events between groups
- Time-restricted eating combined with calorie restriction was not more beneficial than daily calorie restriction alone for reducing body weight or metabolic risk factors
Abstract
The long-term efficacy and safety of time-restricted eating for weight loss are not clear. We randomly assigned 139 patients with obesity to time-restricted eating (eating only between 8:00 a.m. and 4:00 p.m.) with calorie restriction or daily calorie restriction alone. For 12 months, all the participants were instructed to follow a calorie-restricted diet that consisted of 1500 to 1800 kcal per day for men and 1200 to 1500 kcal per day for women. The primary outcome was the difference between the two groups in the change from baseline in body weight; secondary outcomes included changes in waist circumference, body-mass index (BMI), amount of body fat, and measures of metabolic risk factors. Of the total 139 participants who underwent randomization, 118 (84.9%) completed the 12-month follow-up visit. The mean weight loss from baseline at 12 months was -8.0 kg (95% confidence interval [CI], -9.6 to -6.4) in the time-restriction group and -6.3 kg (95% CI, -7.8 to -4.7) in the daily-calorie-restriction group. Changes in weight were not significantly different in the two groups at the 12-month assessment (net difference, -1.8 kg; 95% CI, -4.0 to 0.4; P = 0.11). Results of analyses of waist circumferences, BMI, body fat, body lean mass, blood pressure, and metabolic risk factors were consistent with the results of the primary outcome. In addition, there were no substantial differences between the groups in the numbers of adverse events. Among patients with obesity, a regimen of time-restricted eating was not more beneficial with regard to reduction in body weight, body fat, or metabolic risk factors than daily calorie restriction. (Funded by the National Key Research and Development Project [No. 2018YFA0800404] and others; ClinicalTrials.gov number, NCT03745612.).
Authors
Deying Liu, Yan Huang, Chensihan Huang, Shunyu Yang, Xueyun Wei, Peizhen Zhang, Dan Guo, Jiayang Lin, Bingyan Xu, Changwei Li, Hua He, Jiang He, Shiqun Liu, Linna Shi, Yaoming Xue, Huijie Zhang