Optimizing the lifestyle of patients with type 2 diabetes mellitus - Systematic review on the effects of combined diet-and-exercise interventions.

Aim: To investigate the effects of combined diet-and-exercise interventions in patients with type 2 diabetes mellitus (T2DM).

Data synthesis: A systematic literature search was conducted on PubMed, Web of Science, SPORTDiscus and BISp Surf databases (latest update in June 2024). A total of 14706 records was identified. After screening procedures, 11 randomized controlled trials (n = 24 reports) were included. The included studies compared either the effects of a) a combined intervention versus a diet-only intervention or b) different combinations of diet and exercise. The overall quality of the included study reports was moderate (evaluated with the Risk of Bias 2 (RoB2) tool). Effects of adding exercise to a (calorie-restricted) diet were primarily reflected in increased physical fitness/performance. In far fewer cases, additional beneficial effects on glycemic control, number of subjects taking medication, body weight, body composition, or lipid profile were reported. Combined with regular exercise, an energy-restricted low-carbohydrate (LC) diet with either high-fat (HF) or high-protein (HP) contents showed superior effects compared with an energy-matched conventional (CONV) diet in terms of improvements in medication use (HF-LC versus CONV diet), lipids (HF-LC or HP-LC versus CONV diet) or wellbeing (HP-LC versus CONV diet) in some studies.

Conclusions: Complementing a dietary intervention with regular exercise can have additional health benefits in T2DM, specifically improved physical fitness/performance. LC diets might be superior to other diets when combined with regular exercise. Other diet-and-exercise combinations than those analyzed in this review need to be investigated.

Review registration number: CRD42023458830.