Timing of meal replacement on body weight: a multicenter open-labeled randomized trial

We aim to evaluate the effects of partial meal replacement (MR) with different timing of MR on body weight in Chinese adults.

A multicenter open-labeled, randomized, parallel study was performed. Participants were randomly assigned to receive partial MR at breakfast and lunch or breakfast and dinner for 16 weeks. The primary outcome was the absolute change in body weight between baseline and the end of the intervention. The BMI of participants is between 24.0 kg/m² and 35.0 kg/m², without a history of diabetes, hypertension, or gout, and whose baseline blood pressure, fasting blood glucose, serum level of glycated hemoglobin A1c, uric acid, and liver enzymes within the pre-determined range, were recruited.

A total number of 153 individuals were included in the analysis (106 females and 47 males; mean age 32.6 ± 6.7 years, mean BMI 28.5 ± 2.8 kg/m² at baseline). Partial MR for 16 weeks resulted in significant body weight loss (-5.1 kg, 95% CI: -5.8, -4.5 kg), decrease of waist (-4.8 cm; 95% CI: -5.5 cm, -4.1 cm) and hip circumference (-4.3 cm; 95% CI: -4.9 cm, -3.8 cm), and loss of body fat (-4.1 kg; 95% CI: -4.7 kg, -3.6 kg). About half of the participants (51.6%) achieved the goal of losing 5% of baseline body weight or more. Timings of MR (breakfast and lunch vs. breakfast and dinner) generated similar results.

Partial MR resulted in significant improvements in anthropometric data, body fat, and most metabolic variables while different MR timing generated similar results.

The study was registered at https://www.chictr.org.cn/showproj.html?proj=47475 (ChiCTR2100042637).