Background: Obesity is a public health issue and a worldwide epidemic linked to several major ailments, including diabetes, cancer, and cardiovascular disease. Saudi Arabia has one of the highest rates of overweight and obesity globally, posing a severe threat to the country’s public health.Objectives: To assess the prevalence of overweight, obesity, and high blood sugar among Qassim University medical students. Methods: This cross-sectional study involved medical students at Qassim University, in Saudi Arabia. Results: the prevalence of overweight (27.1%), obesity (14%), sedentary lifestyle (78.8%), poor diet (68.7%) increased weight associated with genetics stood (11.1%), and hyperglycemia among obese medical students (12.1%). Family history of obesity (adjOR = 5.95, 95% CI: 2.94-12.06; p < 0.001), and diet (adjOR = 2.60, 95% CI: 1.27-5.33; p = 0.009), were significantly associated with obesity. Conclusions: A change in sedentary lifestyle and healthy dietary intake is recommended among medical students as a significant association between obesity and diet has been established.