U.S. obesity rates are on the rise, but there’s some good news: Overweight rates among children might be falling—at least in some groups. In one study, sixth-graders who were given help with nutrition and exercise were less obese by eighth grade than a control group. And in a California survey, it appears that obesity rates are decreasing for whites, Asians and Hispanic boys. African-American children were the only group with a still growing obesity rate, with Hispanic girls showing no change. Another study found that the earlier an intervention, the better the chance of weight loss. Of course, the news isn’t all good: The incidence of U.S. childhood obesity has more than tripled in the past 30 years, so in terms of healthy development, we’ve still got lots of room to grow.