The composition of the pre-exercise food intake is known to affect substrate utilization during exercise and thus can affect long-term changes in body weight and composition. These parameters were measured in male rats exercised 2 hours daily over 5 weeks, either in the fasting state or one hour after they ingested a meal enriched with glucose (GLC), whole milk protein (WMP), or -lactalbumin-enriched whey protein (CPL). In comparison with fasting, the GLC meal increased glucose oxidation and decreased lipid oxidation during and after exercise. In contrast, the WMP and CPL meals preserved lipid oxidation and increased protein oxidation, the CPL meal ncreasing protein oxidation more than the WMP meal. At the end of the study, body weight ws larger in the WMP, GLC and CPL-fed rats than in the fasted one. This resulted from an increased fat mass in the WMP and GLC rats and to an increased lean body mass, particularly muscles, in the CPL rats. We conclude that the potential of the CPL meal to preserve lipid oxidation and to rapidly deliver amino-acids for use during exercise improved the efficiency of exercise training to decrease adiposity