THE ROLE OF DAIRY FOODS IN WEIGHT MANAGEMENT
Volume 77, Number 6 November/December 2006
Summary
The cause of overweight and obesity is multifactorial and successful prevention or treatment depends on multiple actions. Although attention has focused primarily on reducing energy (calorie) intake and/or increasing energy expenditure (physical activity), a promising beneficial role for dietary calcium and dairy products in weight management has recently emerged.
In some randomized controlled trials of overweight or obese adults following moderately reduced-calorie diets, increasing consumption of calcium or dairy products from 1 serving or less/day to 3 servings/day (i.e., from inadequate to adequate) has been shown to decrease body weight and body fat beyond that achieved with a reduced-calorie diet alone. Moreover, dairy foods appear to exert a greater beneficial effect on body weight and body fat than calcium alone. Also, consuming 3 servings of dairy foods a day as part of a weight maintenance diet has been demonstrated to improve body composition in overweight adults. Findings from a recent multi-center trial in overweight and obese adults indicate that diets rich in dairy foods increase weight loss by targeting the body fat compartment during energy restriction.
In adults, many, but not all, observational studies support an association between higher calcium or dairy food intake and reduced body weight or body fat. This inverse association has been demonstrated in young and older adults, in women and men, and in those of different racial and ethnic backgrounds.
Most investigations of dairy foods or calcium intake and body weight or body fat in children and adolescents are observational studies. Although these studies cannot prove a cause and effect relationship, they indicate that increasing intake of dairy foods or calcium to recommended levels has no adverse effect on body weight or composition, and, in fact, may help promote a healthy body composition or prevent an unhealthy weight gain. Using data obtained from U.S. children participating in the Framingham Children’s Study, researchers recently found that adequate dairy food intake during preschool years protected against excess body fat gain throughout childhood and in early adolescence.
The ability of calcium or dairy foods to regulate energy metabolism likely involves multiple mechanisms which influence the availability of energy and energy expenditure. Most attention has focused on increasing energy utilization by affecting fat oxidation and hormonal control of fat metabolism. Findings demonstrating that dairy sources of calcium decrease body weight and accelerate fat loss to a greater extent than calcium alone suggest that other bioactive components (e.g., protein) in addition to calcium in dairy foods may be involved.
More research is needed to clarify the anti-obesity effect of dairy products, including the underlying mechanism(s). Although the beneficial effects on body weight or body fat are likely to be modest in comparison to modifications in energy intake and expenditure, consuming 3 servings a day of dairy foods such as reduced-fat or nonfat milk, yogurt, or cheese, may nonetheless substantially contribute to a healthy body weight and composition which, over time, may help reduce the nation’s epidemic of overweight and obesity.
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