Time-restricted eating and exercise training improve HbA1c and body composition in women with overweight/obesity: A randomized controlled trial
Diet modification and exercise training are primary lifestyle strategies for obesity management, but poor adherence rates limit their effectiveness. Time-restricted eating (TRE) and high-intensity interval training (HIIT) improve cardiometabolic health in at-risk individuals, but whether these two interventions combined induce superior improvements in glycemic control than each individual intervention is not known. In this four-armed randomized controlled trial (ClinicalTrials.gov NCT04019860), we determined the isolated and combined effects of seven weeks of TRE (≤ 10-h ad libitum eating window every day) and HIIT (three exercise sessions per week), compared with a non-intervention control group, on glycemic control and secondary cardiometabolic outcomes in women with overweight/obesity. There were no statistically significant effects after isolated TRE, HIIT, or a combination (TREHIIT) on glucose area under the curve during an oral glucose tolerance test (the primary outcome) compared with the control group; TRE: -26.3 mmol/L, 95% confidence interval (CI): -82.3, 29.7 (p = .36), HIIT: -53.8 mmol/L, 95% CI: -109.2, 1.6 (p = .057), TREHIIT: -41.3 mmol/L, 95% CI: -96.4, 13.8 (p = .14). However, TREHIIT improved HbA1c and induced superior reductions in total and visceral fat mass compared with TRE and HIIT alone. High participant adherence rates suggest that TRE, HIIT, and a combination thereof, may be realistic diet-exercise strategies for improving markers of metabolic health in women at risk of cardiometabolic disease.