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, with overweight prevalence reported between 14 –
19 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.
A review of research published 2008 Nutrition Reviews found a positive link between
high calcium intake and improved body composition and weight maintenance across
a range of ages. In this review, researchers looked at data from more than 90 studies
including randomized clinical trials, metabolic experiments and observational studies
that assessed the relationship between calcium and/or dairy intake and the proportion
of fat and lean body mass in the body. The authors concluded that the majority of
research suggests high calcium intake, from sources including dairy foods, may affect
body composition by some combination of reducing body fat mass while maintaining
lean body mass, reducing weight gain, and increasing weight loss on calorie-restricted
diets.4
A study published in December 2008 Journal of the American College of Nutrition
pertaining to adolescents and body composition found that adolescents (ages 12-16
years) with higher daily dairy food consumption had less body fat and a lower body
mass index (BMI) than those with lower daily dairy consumption. The goal of this
analysis was to explore the association between dairy consumption and the level
of body fat among more than 10,000 children (ages 5-11) and adolescents (ages 12-16)
using two of the National Health and Nutrition Examination Surveys (NHANES), 1988-1994
and 1999-2002.5
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.6 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.7 Other studies suggest that
adequate calcium intakes decrease the risk of overweight individuals becoming obese
or developing metabolic syndrome.8
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.
|