Abstract
BackgroundThere exists long-lasting concern, but no substantive evidence, that exercise may cause compensatory eating and compromise its glycemic benefits. We performed a randomized controlled, three-period crossover trial of moderate- and vigorous-intensity endurance exercise (MOD-EX and VIG-EX) intervention to fill this knowledge gap, which was also externally validated in the UK Biobank (UKB) cohort.MethodsIn total, 54 healthy college students (aged 22.2 ± 2.5 years) completed the 5-day WHO-recommended doses of MOD-EX, VIG-EX, or control treatments. Outcomes included dietary responses, assessed by daily weighed dietary logs in ad libitum eating condition, and glycemic control status, assessed both at fasting state and during oral glucose tolerance test (OGTT). Cox proportional hazard models were fitted to estimate associations of the interaction between physical activity (PA) and dietary intake with the risk of type 2 diabetes (T2D).ResultsMOD-EX and VIG-EX did not induce significant increases in total energy intake, but 15.67% (−13.5 kcal/day) decreased vegetable intake and 10.92% ( + 31.1 kcal/day) increased intake of added oil in food for VIG-EX (p < 0.05). MOD-EX and VIG-EX both reduced postprandial glucose (HbA1c: −3.82% [-6.40% to −1.24%] and −2.18% [−4.67% to 0.32%]; 2 h total area under the glucose curve (tAUC) during OGTT: −11.92% [−24.48% to 0.64%] and −13.48%, [−25.34% to −1.63%]). The effect had been masked by 7.52% and 10.85% from diet, respectively, primarily attributing to decreased fiber and increased saturated fatty acid (SFA) intakes ( | factors loadings | >0.4), exactly matching to dietary responses to exercise. Interaction analysis supported that higher fiber (p-interaction=0.022) and lower SFA (p-interaction=0.009) intakes augmented exercise-induced glycemic benefit, which was confirmed in the UKB study (N = 50 162) that participants with higher fiber or lower SFA intake showed more pronounced association between PA and reduced risk of incident type 2 diabetes (p-interaction=0.035).ConclusionsWe provide evidence to recommend dietary fiber supplementation and SFA restriction accompanying exercise training to achieve maximum glycemic improvement.Trial registration Chinese Clinical Trial RegistryChiCTR2100055095. 2021/12/31.https://www.chictr.org.cn/showproj.html?proj=139665</p>