The New York City Department of Health says fewer children are severely obese.

The department compared data of city public school students in grades K through eight between the 2006-07 and 2010-11 school years. The data showed that the number of severely obese children dropped significantly between these periods.

Health officials describe severe obesity as a body mass index at or above 120 percent of the 95th percentile, a determination that can be made by a doctor.

Children with severe obesity have increased health risks of disease including high blood pressure. Obese children are also more likely to become obese adults. To prevent this, the DOH recommends at least one hour of physical activity a day, cutting down on sugar-filled drinks and eating a lot of fruits and vegetables instead of high-calorie snacks and sweets.

The department's findings also showed that severe obesity decreased from 6.3 percent to 5.7 percent in the 2006-07 school year, signifying a 9.5-percent decrease. In the 2010-11 period, obesity declined by 5.5 percent.

Although the numbers might be down for city children, a recent study shows that obesity is increasing nationwide.