For children with sleep apnea, a tonsillectomy to treat the problem might lead to weight gain, HealthDay reports.

Doctors have long known that after the surgery, kids can gain weight at an accelerated clip, Chakravorty said.

But the new study, reported online July 28 and in the August print issue of the journal Pediatrics, offers “certainty” that it’s actually an effect of the treatment, Katz said.

That’s because children in the study were randomly assigned to have surgery or to “watchful waiting” — putting off surgery and staying with other options, such as medications to better control any nasal allergies or asthma symptoms.