Time-restricted Eating and High-intensity Interval Training After Gestational Diabetes

This trial will recruit participants who had gestational diabetes in their most previous pregnancy. Participants will be randomly allocated into two groups: one intervention group and one control group 6-12 weeks after giving birth. The intervention group will undergo an 8-week supervised intervention consisting of time-restricted eating and endurance exercise training with moderate-to-high intensity. The investigators will assess cardiorespiratory fitness, body composition, and other markers of cardiovascular and metabolic health before and after the 8 weeks. Additionally, the participants in the intervention group will be encouraged to continue exercising and eating time restricted after the supervised period and follow them up by telephone until one year from the baseline visit. The investigators will measure the same outcomes at the follow-up as on the previous two test points.

Inclusion Criteria: * Gestational diabetes mellitus in most recent pregnancy * Within 6-12 weeks postpartum * Understands oral and written Norwegian or English * Able to walk or run on a treadmill or ride a bike for at least 60 minutes * Living in the Trondheim area Exclusion Criteria: * Pregnant or trying to become pregnant * Diagnosed with type 1 or type 2 diabetes * Diagnosed with cardiovascular disease * Have a history of eating disorders (anorexia, bulimia, or binge eating disorder) * Habitual eating window of less than 12 hours/day * Engaging in regular high-intensity endurance training (once per week or more) * Intention of starting an exercise programme and/or a dietary strategy within the study period * Shift work that includes night shifts * Bariatric surgery * Any other reason which, according to the researchers, makes the potential participant ineligible