Americans take obesity as seriously as cancer and consider it an even bigger health threat than heart disease -- the nation's leading killer -- yet most do not go beyond traditional diets or involve doctors, a study has found.

According to an obesity poll, conducted by the American Society for Metabolic and Bariatric Surgery (ASMBS) and NORC -- an independent research organisation -- at the University of Chicago, 81 per cent of Americans consider obesity tied with cancer as the most serious health problem facing the country, ahead of diabetes (72 per cent), heart disease (72 per cent), mental illness (65 per cent) and HIV/AIDS (46 per cent). 

Nearly 94 per cent agree that obesity itself increases the risk of an early death, even if no other health problems are present, according to the new poll. 

Yet, despite the seriousness with which they take the threat, the vast majority of Americans incorrectly perceive diet and exercise alone to be the most effective long-term weight loss method, and one in three of those struggling with obesity, report that they have never spoken with a doctor or health professional about their weight, the researchers said. 

"This survey reveals that Americans understand the risks of obesity better than ever, but hold major misperceptions about the causes of the disease, the effectiveness of the different treatments and the importance of involving the medical community in their care," said Raul J. Rosenthal, President, ASMBS and Chairman at Cleveland Clinic, Florida.

Further, the poll finds about 60 per cent of Americans are currently trying to lose weight, although 94 per cent with obesity have tried before.

Seventy eight per cent Americans consider diet and exercise to be the most effective method for long-term weight loss, saying it's even more effective than weight loss surgery and prescription obesity drugs.

The survey shows there's a significant need for education so that Americans can better match the health risks and impact of obesity on their lives with the actions they take and the treatments they choose, the researchers noted.

For the study, the team conducted a survey of 1,509 adults. The findings were presented during the Obesity Week 2016 event in New Orleans, US.