Children who do not get enough sleep are more likely to be overweight than those who get more, according to a study published yesterday that tracked more than 2,000 US kids for five years.

Researchers at Northwestern University in Evanston, Illinois, used detailed diaries kept by families to examine children's sleep behavior and its relationship with weight.

"Children who get less sleep tend to weigh more five years later," lead researcher Emily Snell said in an interview.