According to a review of the published scientific literature, claims that low-fat dairy products or calcium can help people lose weight are untrue. Neither dairy products in general nor calcium intake promote weight loss.
Out of 49 clinical trials, 41 showed no effects of diary or calcium on weight, two showed an increase in body weight with a dairy regimen, and one showed a lower rate of weight gain. Only five showed weight loss.
An association between calcium or dairy intake and weight loss has been seen in some "observational" studies, possibly due to other factors such as increased exercise, cutting out high-calorie foods with little nutritional value, or other diet changes.