Published data describing the inverse relationship between calcium intake and body weight in 564 women were evaluated for their dispersion around their means, and the fraction above any given weight or rate of weight gain was calculated from the parameters of the normal distribution for the variable concerned. At the 25th percentile of calcium intakes, 15% of young women were overweight, and that fraction fell to only 4% at calcium intakes in the range of currently recommended values. Similarly, obesity prevalence in this cohort fell from 1.4 to 0.2% across the same difference in calcium intakes. At midlife, women at the 25th percentile of intakes gained weight, on average, at a rate of 0.42 kg/y. This gain dropped to -0.011 kg/y at currently recommended calcium intakes. Although calcium intake explains only a small fraction of the variability in weight or weight gain, shifting the mean of the distributions downward by increasing calcium intake can be estimated to reduce the prevalence of overweight and obesity by perhaps as much as 60-80%.