Children who are overweight and eat too much risk the binge eating disorder bulimia as adults, say psychiatrists.
Bulimics had overeaten and were overweight as children
The assumption is based on a study of 154 twin sisters where one of the pair developed an eating disorder.
Those with bulimia had often gorged food and been less picky about what they ate as children, the King's College London investigators found.
They presented their findings to a Royal College of Psychiatrist's conference in Edinburgh.
The mothers of the twins were asked to fill in questionnaires about their daughters' childhood feeding patterns.
Siblings who had gone on to develop bulimia in adulthood were significantly more overweight, less picky and ate more as children, compared with their healthy siblings.
Conversely, being a picky eater as a child appeared to protect against bulimia in later life.
But childhood eating habits did not predict future risk of anorexia.
Things like not eating enough, eating non-food items such as wallpaper, having unpleasant meals between the ages of one and 10 or selective eating during the first year of life did not predict an eating disorder in later life.
The study authors, Dr Nadia Micali and colleagues, suggest what they called a '"disinhibited" eating style - overeating to obesity - could be an individual risk factor for bulimia.
They recommended more research to test their theory.
If proven, this could have important implications for the prevention of eating disorders, they said.
Deanne Jade, principal of the National Centre for Eating Disorders, said it was understandable how children who were obese could go on to develop bulimia.
"If a child is overweight they are subject to teasing and are likely to be very sensitive about their bodies.
"Consequently, they are more likely to diet and it's that, more than anything, which is a risk factor for bulimia.
"Dieting changes someone's relationship with food and, generally speaking, will create cravings that can lead to bingeing and strategies to correct the bingeing."
But she said it didn't make sense that overeating on its own would lead to bulimia.
"I do not think you can say one child is fundamentally more greedy and therefore bulimic," she said.
Susan Ringwood, chief executive of the Eating Disorders Association, said: "We welcome any findings that draw attention to this very complex issue as so much more needs to be done to enable people to understand how serious these conditions can be.
"The sooner someone gets help, the more likely they are to make a good recovery."