Children with sleep apnea are often told to undergo tonsillectomy. But, a new research shows that the surgery in fact increases the risk of weight gain.

Although tonsillectomy, the procedure to remove tonsils, is relatively safer, it has certain side effects. Researchers examined 204 children who were recommended the surgery and another 192 children acted as control group. All the children were aged between 5 and 9.

The children were tracked for seven months. Researchers found that children who underwent tonsillectomy gained more weight than those who did not get the surgery. The team noted that the overall weight gain was small and was almost negligible in children with normal weight. Those who were overweight, researchers found that the extra pounds increased obesity risk in them.

The analysis showed that 52 percent of children who were overweight before tonsillectomy gained more weight seven months after the procedure. The control group saw only 21 percent of overweight children becoming obese during the study duration.

Researchers suggested that children with sleep apnea should follow a healthy lifestyle.

"You can't just treat the sleep apnea. You have to have nutrition and lifestyle counseling, too," said lead researcher Dr. Eliot Katz, a respiratory disease specialist at Boston Children's Hospital, reports HealthDay. "After surgery, parents are often very satisfied. Their kids are sleeping better, and they may be better behaved and doing better in school. But there's this insidious issue of weight gain."

The association between weight gain and tonsillectomy remained unclear. However, researchers explained that as children no longer have difficulties breathing during sleep, they could be burning fewer calories. Moreover, more sleep reduces hyperactivity during the daytime, which would then reduce the total number of calories burned throughout the day.

The study, 'Growth After Adenotonsillectomy for Obstructive Sleep Apnea: An RCT,' was published in the journal, Pediatrics.