Medical studies have suggested an association between diet lacking adequate amounts of calcium and a higher body weight. Therefore, some experts have suggested that augmenting calcium intake may affect weight. Data from nine trials reveal a fairly consistent calcium association. Each 300 mg increase in regular calcium intake per day was associated with approximately 1 kg less body fat in children and 2.5-3.0 kg lower body weight in adults. The authors concluded that these data suggest that increasing calcium intake by the equivalent of two dairy servings per day could reduce the risk of overweight substantially, perhaps by as much as 70 percent (1). Alternatively, a recent evaluation of calcium supplementation (1000 milligrams per day) in 100 women did not find a significant difference in body weight or fat mass between calcium and placebo users over 25 weeks of the study (2). Therefore, more studies are needed to clarify this potentially exciting area of research.

References:

(1) Heaney RP, Davies KM, Barger-Lux MJ. Calcium and weight: clinical studies. J Am Coll Nutr. 2002 Apr;21(2):152S-155S.
(2) Shapses SA, Heshka S, Heymsfield SB. Effect of calcium supplementation on weight and fat loss in women. J Clin Endocrinol Metab. 2004 Feb;89(2):632-7.