Dialysis patients as a group appear to have a caloric intake less than the recommended values; because their energy expenditure is not different than that of healthy adults, they should be in negative caloric balance and lose body mass progressively. We retrospectively analyzed our data in a group of peritoneal dialysis patients who had dietary evaluations and kinetic measurements performed two consecutive times over a period of 6 months. Body weight, lean body mass (LBM), fat mass, and anthropometric parameters remained stable over this period of time, suggesting that these patients are not in negative energy balance. When their daily caloric intake was normalized to a new ideal body weight derived from the LBM calculated from creatinine kinetics, the values were within normal limits, suggesting that these patients were in zero energy balance; hence, a stable body mass was expected.