Obesity is increasing in the United States in epidemic proportions. Epidemiologic data suggest that people with high calcium intake have a lower prevalence of overweight, obesity, and insulin resistance syndrome. Studies in transgenic mice have demonstrated that calcium influences adipocyte metabolism. High calcium intake depresses levels of parathyroid hormone and 1,25-hydroxy vitamin D. These decreased hormone levels cause decreases in intracellular calcium, thereby inhibiting lipogenesis and stimulating lipolysis. High dietary calcium intakes also increases excretion of fecal fat and may increase core body temperature. Calcium from dairy products seems to have more of an impact than calcium from dietary supplements. Primary care providers should include recommendations about adequate calcium intake in standard dietary counseling about weight management.