A survey by the Priory Clinic found 43% of adults in Britain eat to change a negative mood.
However, a quarter feel guilty after eating and another quarter feel the route to happiness is to be thinner.
The Eating Disorders Association said the findings were worrying and reflected the pressures society places on image.
Peter Smith, eating disorders specialist at the Priory Hospital in Roehampton, agreed.
“Contemporary society’s veneration of thinness, our acceptance of distorted body images in the media and the relentless pressure on women and men to conform to a certain body type means increasing numbers of people will be affected by potentially life-threatening mental health issues related to food, weight and body image,” he said.
His team found many people use food to deal with their emotions. The survey of 2,000 people showed 47% of adolescents aged 16-24 and 40% of those aged 35-44 had eaten because they were bored. A quarter of women and people aged 45-54 had eaten because they were stressed. Others ate after arguing with spouses or partners.
The Priory Group has witnessed a significant rise in females aged 17 to 30 presenting with both eating disorders and addictions.
Mr Smith said: “These patients binge and vomit, then don’t eat - their symptoms oscillate, reflecting a ceaseless struggle with their weight, eating and emotions. The sufferer’s symptoms often go unnoticed by family, friends and the medical profession.”
He said the medical profession needs to change its stereotyped image of the typical eating disorder patient. “We now know the most common eating disorders also affect the high-achiever in her mid-thirties to mid-fifties who is successful in most facets of her life, yet suffers from either bulimia nervosa or a binge eating disorder as a dysfunctional method of coping with low self-esteem, stress, insecurity and other issues,” he said.
A spokesman from the Eating Disorders Association said eating disorders were about emotions, not food. “When you look at how the eating disorder developed it goes to show that emotions affect the way that we eat,” he said. “It’s indicative of some of the pressures that society puts on people today. When you look at nearly half of adolescents eating because they are bored, you realise the struggle you have in terms of obesity.”