It has been well documented that the prevalence of overweight and obesity in both adults and children has increased in recent years. Data from the 2005–06 NHANES survey shows that among United States adults, the prevalence of obesity was 34 percent. This represents more than double the obesity in the past three decades. In 2003–04, an estimated 66 percent of adults were classified as overweight. Data from two NHANES surveys (1976–1980 and 2003–2004) show that the prevalence of overweight in children and adolescents is increasing as well. For children aged 2–5 years, prevalence increased from 5 percent to 14 percent; for those aged 6–11 years, it increased from 7 percent to 19 percent; and for those aged 12–19 years, it increased from 5 percent to 17 percent.¹

Some research suggests that consuming three servings of milk, cheese or yogurt each day as part of a nutrient-rich, balanced diet may help maintain a healthy weight. A number of observational studies suggest that those who consume greater amounts of dairy foods tend to weigh less than those who consume less dairy. Other studies have not found consistent results for the relationship between dairy or calcium consumption and weight loss.^2,3 This is an area that requires continued research.

Many studies have been done to examine the link between dairy intake and weight. A 2004 study by Zemel et al concluded that individuals who consume three servings of dairy each day while on a reduced-calorie diet lose significantly more weight than individuals consuming the same calorie-level low-dairy diets.⁴ It is unclear which component of dairy foods is responsible for the effect on body weight. A study by Lin et al examined the effect of calcium on weight loss in adult women and found that weight loss was associated with calcium specifically from dairy sources rather than supplemental sources.⁵ Other studies suggest that adequate calcium intakes decrease the risk of overweight individuals becoming obese or developing metabolic syndrome.⁶

There are several possible explanations for how dairy and calcium affect body weight. There is some evidence that calcium, specifically from dairy products, may help burn fat—which may result in less fat being stored. Some researchers suggest that the protein content of dairy products leads to earlier satiety, which helps with weight maintenance. Any effect is small, but over time could result in enhanced weight loss or better weight management.

Dairy products contribute only 9 percent of the calories in the United States food supply, yet provide a large proportion of several essential nutrients such as protein, calcium, potassium, magnesium and vitamins A, B12 and D. Dairy products (widely available in fat-free or low-fat versions) can play an important role in weight-management plans, while conferring additional health benefits in terms of bone health, hypertension and colon cancer, to name a few.