About a third of children get recurrent infections and research presented at a US conference suggests the link.
Infections may affect food choices by damaging nerves involved in taste, the researchers said.
However, a number of UK experts raised doubts about the findings, with one saying a link was “extremely unlikely”.
Five separate studies aired at the American Psychological Association’s conference hinted at an association between either ear infection or tonsil removal surgery and obesity.
A survey of almost 14,000 people found that those who had had tonsils removed were 40% more likely to be overweight as adults.
For another study, more than 6,000 adults were quizzed about their history of ear infections and the results suggested that those with a moderate to severe history were 62% more likely to be obese.
However, UK experts raised doubts about the strength of the findings.
Paediatric ear, nose and throat surgeon Ray Clarke, from Alder Hey Children’s Hospital in Liverpool, said it was well known that severe ear infections, and operations, could affect taste. However, he said there was no other evidence that this could play a role in developing obesity.
Professor Mark Haggard, from the charity Deafness Research UK, said while there was a small chance that there might be an underlying genetic predisposition to both severe ear infections and obesity, the associations found here should not be overplayed.
“A connection is not impossible, but to be frank, is extremely unlikely,” he said.