The aim of this study was to compare changes of nutrient intakes and nutritional status of selected minerals, during a three-month weightloss program using diets with distinct energy contents. 62 obese women (age 33.2 +/- 8.3 years; BMI 34.6 +/- 3.4 kg/m2) were allocated to two diets, one supplying 1000 kcal/d (Diet 1), and the other 1300 kcal/d (Diet 2). Before and after 3 months, intakes of iron (Fe), zinc (Zn), copper (Cu), and calcium (Ca) were evaluated through self-reported three-day dietary records. Selected laboratory parameters related to the nutritional status of iron, zinc and copper were analyzed: hemoglobin, serum ferritin, zinc-protoporfirin, transferrin saturation, plasma zinc, hair zinc, and plasma copper. Mean weight loss was 10.8% on Diet 1 and 8.5% on Diet 2 (p = 0.29). Intakes of Fe, Zn, Cu and Ca decresed by 50%, 30%, 40%, and 9%, respectively. The change of serum ferritin was significantly greater in the group on Diet 1 (p = 0.04), in > or =10% of weight loss subjects (p = 0.006) and in patients with lower protein intake (p = 0.033). Others parameters studied, although tended consistently to present greater disturbances in subjects receiving the 1000 kcal/d diet, they did not reach statistical significance. The prescription of weight-reducing diets with 1000 y 1300 kcal/d did not produce major effects on the nutritional status of minerals during the first three months of treatment, except by the significant detriment of body iron stores in subjects receiving the 1000 kcal diet, as indicated by the changes of serum ferritin.