Adding Different Exercise Training Volumes to a Diet-Induced Weight Loss Facilitates Fat Loss and Maintains Fat-Free Mass in a Dose-Depending Fashion in Persons with Newly Diagnosed Type 2 Diabetes: Secondary Findings from the DOSE-EX Multi-Arm, Parallel-Group, Randomized Trial

OBJECTIVE To assess the dose-response effects of exercise in combination with a diet-induced weight loss on fat mass (FM) percentage (FM%) in persons with diagnosed type 2 diabetes. RESEARCH DESIGN AND METHODS In this secondary analysis of a four-armed randomized trial ( Clinicaltrials.gov NCT03769883 ) 82 persons (35% females, mean age and standard deviation (SD) 58.2 (9.8) years) living with type 2 diabetes were randomly allocated to the control group (N=21, CON), diet control (25% energy restriction; N =20, DCON), diet control and exercise three times/week (two sessions of aerobic and one session combining resistance and aerobic training; N =20, MED), or diet control and exercise six times/week (four sessions of aerobic and two sessions combining resistance and aerobic training; N =21, HED) for 16 weeks. The primary outcome was the change in FM percentage points (pp). Secondary outcomes included fat-free mass and visceral adipose tissue volume. RESULTS Type 2 diabetes duration was 4.0 years (interquartile range 1.9 to 5.5), body weight (SD) 101.4 kg (14.6), FM% (SD) 39.4 (6.7). FMpp decreased compared to standard care −3.5 pp (95% CI −5.6 to −1.4) p=0.002, −6.3 pp (CI −8.4 to −4.1) p<0.001, and −8.0 pp (95% CI −10.2 to −5.8) p<0.001, for DCON, MED, and HED, respectively. The difference between HED and MED was −1.8 pp [95% CI −3.9 to 0.4]; p=0.11). CONCLUSIONS All interventions were superior in reducing FMpp compared to standard care in a dose-dependent manner. Adding three or six sessions of exercise to a low-calorie diet was superior in reducing FM compared to a low-calorie diet alone. Article Highlights Why did we undertake this study? Exercise and weight loss are recommended for persons with type 2 diabetes. It is unclear if adding exercise, and which amount of exercise, to a low-calorie diet supports additional fat mass loss. What is the specific question(s) we wanted to answer? What is the dose-response effect of exercise combined with a moderate caloric restriction on changes in fat mass? What did we find? Adding exercise to a diet-induced weight loss reduced fat mass and preserved fat-free mass in a dose-dependent manner. What are the implications of our findings? Adding exercise to a moderate caloric restriction dose-dependently facilitates reductions in fat mass by enlarging weight loss and fat loss.