Dr John Morgan, who runs the Yorkshire Centre for Eating Disorders in Leeds, said that for every man with an eating disorder there were 10 more who desperately wanted to change the way they looked.
"One in five young men have some degree of quite extreme distress," BBC quoted him, as saying.
Morgan said that he had also seen a significant rise in the number of men with anorexia and bulimia.
The official estimate for the number of men with an eating disorder stands at around 10-15 percent of all sufferers, but actual figure is much higher.
"We know that 1 in 20 young people suffer from some degree of disordered eating and that at least 15 percent of them are men and yet that's a tip of an iceberg," he said.
"There are men who have problems with compulsive exercise and excessive bodybuilding who have an illness, but we haven't defined them. Our definitions of illness have been focused on women, rather than men," he added.
In 2000, a report for the Eating Disorder Association found that not enough was being done to help care for men with eating disorders.
Eight years on Morgan says that the situation has become worse.
"When the report was written there were some units that had dedicated expertise in male eating disorders. A couple of these have now closed down," he said.
"There's a lack of funding, a lack of interest. You're dealing with a situation where you're trying to develop a national service for men across the country, but the Health Service is now more focused on the local "seriously ill
According to Morgan, images of male beauty in the media are part of the problem, and that there's now just as much pressure on young men to look slim as there is on women.