Milk is widely promoted as a healthy beverage for children, but some researchers believe that estrone and whey protein in dairy products may cause weight gain, and others claim that dairy calcium promotes weight loss.
Researchers from the US Brigham & Women's Hospital and Harvard Medical School tracked the height, weight and food intake of 12 829 children aged 9 to 14 years, over three years .
Their objective, to assess any links between milk, calcium from foods and beverages, dairy fat, and weight change over time.
"Quantities of 1 per cent milk (boys) and skim milk (girls) were significantly associated with BMI gain, as was total dietary calcium intake," conclude the researchers.
Children who drank the most milk gained more weight, drinking large amounts of milk may provide excess energy to some children, they add.
They estimated links between annual change in body mass index (BMI) (calculated as weight in kilograms divided by height in meters squared) and dietary factors, adjusted for adolescent growth and development, race, physical activity, inactivity, and (in some models) total energy intake.
"Children who drank more than three servings a day of milk gained more in BMI than those who drank smaller amounts," they add.
Multivariate analyses of milk, dairy fat, calcium, and total energy intake suggested that energy was the most important predictor of weight gain.
Analyses of year-to-year changes in milk, calcium, dairy fat, and total energy intakes provided generally similar conclusions: an increase in energy intake from the prior year predicted BMI gain in boys.
Full findings for the US study are published in the June issue of the Archives of Pediatrics & Adolescent Medicine.