This randomized, double-blind, placebo-controlled study was conducted to compare the effect of a 15-week weight-reducing programme (2 2900 kJ/d) coupled with a calcium plus vitamin D (calciumþ D) supplementation (600 mg elemental calcium and 5 mg vitamin D, consumed twice a day) or with a placebo, on body fat and on spontaneous energy/macronutrient intake. Sixty-three overweight or obese women (mean age 43 years, mean BMI 32 kg/m 2 ) reporting a daily calcium intake , 800 mg participated in present study. Anthropometric variables, resting energy expenditure and spontaneous energy intake were measured before and after the 15-week programme. The calciumþ D supplementation induced no statistically significant increase in fat mass loss in response to the programme. However, when analyses were limited to very low-calcium consumers only (initial calcium intake #600 mg/d, n 7 for calciumþ D, n 6 for placebo), a significant decrease in body weight and fat mass (P,0·01) and in spontaneous dietary lipid intake (P,0·05) was observed in the calciumþ D but not in the placebo group. In very low-calcium consumers, change in fat mass was positively correlated with change in lipid intake. During the weight-reducing programme, a calciumþ D supplementation was necessary in female overweight/obese very low-calcium consumers to reach significant fat mass loss that seemed to be partly explained by a decrease in lipid intake. We propose that this change in lipid intake could be influenced by a calcium-specific appetite control. The hypothesis that calcium/dairy supplementation might accentuate fat mass loss in the context of a weight-reducing programme in obese individuals compared to a non-supplemented control condition has been demonstrated in some (1,2) , but not all (3) studies. One explanation for this discrepancy could be the difference in habitual calcium intake of participants. Indeed, based on results showing that women consuming less than 600 mg calcium/d had an increased percentage body fat (4) , the existence of a threshold of usual calcium intake below which a supplementation in this mineral would effectively promote fat mass loss is possible. The first objective of the present study was to investigate this hypothesis and to assess the impact of a calcium plus vitamin D (calciumþD) supplementation on the outcome of a weightreducing programme in female low-and very low-calcium consumer (VL-CC) overweight/obese subjects.Up to now, the potential effect of calcium on energy balance and adiposity has been explained by a suppression of calcitriol (1,25-dihydroxyvitamin D) which decreases intra-adipocyte calcium influx and concentration (5) leading to a reduced lipogenic gene expression and stimulation of lipolysis and adipocytes uncoupling protein 2 expression (6,7) .Moreover, a diet high in calcium was also shown to increase 24 h lipid oxidation (8) and to reduce lipid absorption due to the intestinal formation of calcium-fatty acids insoluble 'soaps' that are excreted in the faeces (9) . From another perspective, the idea of ...