We have studied changes in energy expenditure and body composition in adult males with Emery-Dreifuss muscular dystrophy, age-matched males with hyperCKemia and age-matched healthy controls. All participants were studied twice, 2-3 years apart. Resting energy expenditure was studied by indirect calorimetry, lean body mass and body fat by dual X-ray absorptiometry, and muscle mass was estimated based on 24-h urinary creatinine excretion. At baseline and 2-3 years later, body fat was significantly higher (P < 0.011 and P < 0.003, respectively) and lean body mass significantly lower (P < 0.024 and P < 0.012, respectively) in patients with Emery-Dreifuss muscular dystrophy as compared to subjects with hyperCKemia and healthy controls. Resting energy expenditure, over the study period, increased significantly in patients with Emery-Dreifuss muscular dystrophy (P < 0.031), but not in patients with hyperCKemia nor in healthy controls. Our study suggests that patients with Emery-Dreifuss muscular dystrophy may have increased energy expenditure relative to healthy subjects. If not met by increased caloric intake, this greater energy expenditure may partially contribute to a further deterioration in their muscle performance.