Obesity and overweight are serious health problems in the U.S., with an estimated 65% of adults either obese or overweight as of 2002, and among children and adolescents the prevalence of overweight has nearly tripled over the past two decades to 16 %. Modest weight loss and body fat reduction can reduce the risks of obesity. Recent laboratory studies have described potential cellular mechanisms for calcium and its role in lipid metabolism, and several observational studies have suggested a possible relationship between dairy/dietary calcium and weight loss or body fat reduction. However, randomized studies have mixed results as to whether dairy product or calcium supplementation significantly correlates with decreased weight or body fat when compared to controls. Despite promising findings, further studies are needed regarding this issue.