The aim of this study was to compare the effects of an aerobic training program with a strength training program on body composition and energy expenditure in overweight or obese (29.06 ± 3.49 kg/m2) young adults (21.96 ± 1.90 years). Subjects (N = 109) were randomly assigned to one of three groups: a control group (CG), an aerobic training (AT) group and a strength training (ST) group. Training took place over twelve weeks comprising three sessions per week with each session lasting 60 to 90 minutes. Before and after the program, weight, height, body mass index, lean mass percentage and fat mass percentage were evaluated. In addition, The International Physical Activity Questionnaire-Short Form (IPAQ-SF) was used to estimate energy expenditure. The results of both aerobic training and strength training produced statistically significant improvements in weight (AT-CG = -2.892 kg; ST-CG = -2.986 kg); BMI (AT-CG = -1.075 kg/m2; ST-CG = -1.118 kg/m2); total body fat (AT-CG = -1529.172 g; ST-CG = -763.815); and total body fat percentage (AT-CG = -1.421%; AT-ST = -0.855%). These two exercise prescription models were therefore useful in reducing overweight and obesity, which could have an impact on improving the health and quality of life of individuals with these characteristics.