A cross-sectional study was conducted to evaluate 199 health sciences students in the city of Iquitos. Their socio-demographic characteristics, lifestyle, level of physical activity, type of food, substance abuse, and prevalence of overweight and obesity were ascertained using purpose-validated questionnaires, i.e., the Systematic Alcohol Consumption Interview (Interrogatorio Sistematizado de Consumos Alcohólicos/ISCA), a questionnaire on the frequency of dietary intake (CFCA), the International Physical Activity Questionnaire (IPAQ), and anthropometric measurements. The prevalence of overweight (body mass index (BMI) of 25.0–29.9 kg/m2) was 26.5% (95% CI = 19.9–33.0%) and that of obesity (BMI ≥ 30.0 kg/m2) was 7.9% (95% CI = 3.8–12.1%). A total of 34.4% of students (95% CI = 27.4–41.4%) presented with a BMI > 25 kg/m2. The frequency of overweight was significantly higher in persons aged over 20 years (OR = 2.5) and smokers (OR = 3.2), and the frequency of obesity was significantly higher in older students (OR = 4.1) and males (OR = 5.5). In conclusion, a considerable proportion of health sciences students in the Amazonia region presented with a high BMI. The proportion of students with overweight was higher among students aged over 20 years and smokers, while that of obesity was also higher among males. In the university setting, the development of more overweight-and obesity-preventive activities and educational interventions would therefore be desirable.