Exercise or exercise and diet for preventing type 2 diabetes mellitus

Area of Science:

• Lifestyle Medicine
• Preventive Cardiology
• Metabolic Health

Background:

• Type 2 diabetes incidence is linked to 'Westernized lifestyle' factors like diet and physical inactivity.
• Intensive lifestyle interventions may prevent or delay diabetes in high-risk populations.

Purpose of the Study:

• To evaluate the effectiveness of exercise and/or diet interventions in preventing type 2 diabetes mellitus.

Main Methods:

• Systematic review and random-effects meta-analysis of randomized controlled trials (RCTs).
• Searched multiple databases (Cochrane Library, MEDLINE, EMBASE, etc.) for studies of at least six months duration.
• Included RCTs reporting diabetes incidence in at-risk individuals; two authors assessed quality and extracted data.

Main Results:

• Combined exercise and diet interventions reduced diabetes risk by 37% (RR 0.63) compared to standard recommendations.
• These interventions also led to favorable changes in weight, BMI, waist-to-hip ratio, and waist circumference, with high heterogeneity.
• Improvements were observed in systolic and diastolic blood pressure, but effects on blood lipids were modest. Exercise-only interventions showed no significant impact on diabetes incidence.

Conclusions:

• Combining exercise with dietary changes effectively decreases type 2 diabetes incidence in high-risk groups (impaired glucose tolerance, metabolic syndrome).
• Further research is needed on exercise-only interventions and the long-term effects of combined lifestyle changes on quality of life, morbidity, and mortality, particularly cardiovascular outcomes.