Changes in weight and body composition during the first semester at university. A prospective explanatory study

► This is the first European prospective study on weight gain in university students. ► We used objective measures of BMI, body composition and waist circumference. ► The first semester at university is a critical period for weight and fat gain. ► Being male and living in a student residence influence BMI and fat% negatively. ► We should promote healthier food choices when eating out-of-home.