“Denial can be a coping mechanism,” said Arnaldo Perez, a doctoral candidate at the University of Alberta who researches what motivates families to seek help for their overweight children. Before judging them outright, providers should explore parents’ possible feelings of guilt and failure, he said.

Denial may also be a form of wishful thinking.

It is “natural for a parent to want to think optimistically about their child,” Dr. Thomas N. Robinson, a professor of pediatrics and director of the Center for Healthy Weight at Stanford and Lucile Packard Children’s Hospital Stanford, wrote in an email.

“I have parents tell me that they waited to address it because they thought their child would ‘grow out’ of their extra weight,” he added.