Fat American children: many causes, a lifetime of effects

Eating habits, physical activity, access to parks, ethnicity, poverty and TV watching all play a role in the epidemic, as do many other factors.

The percentage of American children who are overweight or obese has been growing for decades, and now nearly one in three has a body mass index that's greater than normal. Although evidence suggests that obesity rates are leveling off overall, for some groups of kids — especially poor or minority kids — the problem continues to grow, according to a study published Tuesday in the journal Health Affairs.

-- By Jill U. Adams