According to Get Active! | CDC and Healthcare Triage,

• Physical activity reduces stress and improves mood, hence reducing unhealthy behaviors like smoking, excess alcohol use, and unhealthy eating. In terms of diabetes prevention, physical activity improves insulin sensitivity.
• Sufficient physical activity (≥ 150 min of moderate activity per week for adults, 60 min daily for adolescents) benefits physical and mental health in several other ways, too.​
• Some physical activity is better than none.

This video shows (using peer-reviewed evidence) that exercise improves overall health in several ways, hence helping prevent and manage type 2 diabetes: https://youtu.be/SFBBjynBpSw