Time Restricted Eating versus Daily Calorie restriction for Weight Loss

Time restricted eating (TRE) has become one of the most popular diets in recent years. It involves restricting individuals’ eating window to 4-10 hours per day and fasting with energy-free beverages for the remaining hours. The sudden rise in popularity of TRE may be because it does not require individuals to count calories to lose weight. However, long-term randomized trials evaluating the efficacy of TRE are limited. The goal of this study was to compare the effects of 8-h TRE versus traditional calorie restriction (CR) and controls on body weight, metabolic risk factors, mood, and quality of life, over 12-months. Participants with obesity (n = 90) were randomized to 1 of the 3 groups: (1) 8-h TRE (ad libitum eating 12-8pm); (2) CR (25% energy restriction daily); or (3) control (eating over >10 h per day) over 12 months. 77 participants completed the study (40  11 y; 33% Black; 46% Hispanic). By month 12, TRE and CR decreased body weight by -4.87% (95%CI, -7.61% to -2.31%) and -5.30% (95%CI, -9.06% to -1.54), respectively, relative to controls, with no difference between TRE and CR. Energy intake decreased with TRE (-425  531 kcal/d) and CR (-405  712 kcal/d), with no difference between groups. TRE participants were adherent to their eating window 6.1 days per week, while 61% of CR participants were adherent to their diet over 12 months. Fat mass, waist circumference, and BMI decreased by TRE and CR, versus controls, while lean mass and visceral fat mass remained unchanged. Insulin sensitivity increased by TRE compared to controls, but not compared with CR. Blood pressure, heart rate, plasma lipids, fasting glucose, fasting insulin, insulin resistance, HbA1c, mood, and quality of life remained unchanged in the TRE and CR groups, relative to controls. These findings suggest that TRE is more effective in producing weight loss when compared with controls, but not more effective than CR, in a racially diverse population.