Healthcare professionals from across the country meet today to discuss obesity.
The National Obesity Forum will be told the government is not yet taking the issue seriously enough.
Dr Ian Campbell, the forum's president, will call for obesity to be tackled head on by GPs and government bodies.
Speaking ahead of the forum conference in London, he said: "At the moment too little is being done, and too late.
"Waist circumference is an incredibly useful tool when it comes to identifying how at risk a person is from heart disease and diabetes, but it's not yet being used widely enough."
Dr Campbell said that a circumference of more than 40 inches for a man, or 35 inches for a woman, was dangerous.
He added: "Members of the public are going to see family doctors, but they are not getting the help they need when it comes to obesity.
"This conference is crucial because it gives health professionals a chance to learn about the latest research and hear about medical breakthroughs.
"Many workers face a lack of resources and a lack of support. An event like this gives them the chance to meet other in a similar situation."