"Calories are still the bottom line," Novotny tells WebMD. "Does the composition of calories matter? Yes, having more of them come from calcium-rich foods is associated with lower weight and lower body fat."
In light of the current obesity epidemic, Novotny says these findings might provide a new way to help set up children for a healthy body weight later in life. Although reducing overall calorie intake and increasing physical activity are the most effective means to promote weight loss and reduce body fat in people of any age, she says a relatively small change in calcium intake might also lower body fat.
"What perhaps is important about this is that they are in a period of rapid growth, and because of that growth there is an opportunity to modify their body composition," says Novotny. "It sets the stage for future body composition."
The exact mechanism behind calcium's fat-fighting power is not fully understood, but previous research in animals suggests that high levels of calcium in the bloodstream slow down fat production and help shift the body's focus from accumulating fat to breaking it down.
Registered dietitian Althea Zanecosky says the old adage, "like mother, like daughter" usually doesn't apply to weight control methods, but this study shows that it can.
"As a dietitian, I'm really thrilled because here's a food we're trying to get them to eat for other reasons, and now here's this added bonus," says Zanecosky, who is also spokeswoman for the American Dietetic Association.
"Preventing bone disease coming years down road might not be an incentive for girls," Zanecosky tells WebMD. "But for those concerned about their weight, this is one more reason for them to drink their milk because it may also have this beneficial effect on their weight."
Zanecosky says it's not hard for parents to sneak extra doses of calcium-rich foods into their children's diet. As a mother of two adolescent daughters herself, she finds the following "tricks" especially effective in her own children: