The size-zero obsession could be forcing women into extreme diets followed by periods of bingeing on junk food, an expert said yesterday.

Janet Treasure, of the Institute of Psychiatry at King’s College London, said animal studies showed that starvation followed by bingeing on highly palatable foods, such as burgers or chocolate, could alter the way that the brain responds to food.

She said that the fashion industry’s obsession with thinness not only put models at a high risk of developing eating disorders, but inspired imitation among the general public.

“There’s a tendency to break the diet when you see these highly palatable foods,” she said. “That sets it up so you get into a cycle of intermittent naughtiness. It gets you into a momentum – hooked on that sort of cycle.”

Professor Treasure, a specialist on eating disorders, said that the pattern was known as “binge priming”.

In an editorial published in the British Journal of Psychiatry she said that studies on animals, which simulated periods of self-denial followed by exposure to highly palatable foods, led to binge eating and to a susceptibility to addictive behaviours. “If, after a period of food restriction, animals are intermittently exposed to highly palatable food they will significantly overeat.

“This pattern continues when their weight is restored. This tendency to overconsume or ‘binge’ when exposed to highly palatable foods remains several months after the period of binge priming. Translating into the human situation we would predict that binge priming caused by irregular dieting and/or extreme food restriction, interspersed with intermittent consumption of snacks and other highly palatable food, might lead to permanent changes in the reward system.”

If this happened in adolescence, when the brain was more susceptible to rewards, it might lead to persistent eating problems, she said. People exposed to binge priming may also be more prone to substance misuse.

The editorial, co-written with Elizabeth Wack and Marion Roberts, also of the institute, said that models were put at serious risk because of the culture of thinness in the fashion industry. “Beyond the catwalk there are wider public health implications,” they wrote. “The promotion of the thin ideal, in conjunction with the ready access to highly palatable foods, produces a binge-priming environment.

“This might explain the exponential increase in eating disorders seen in women born in the last half of the 20th century and, in part, also contributes to the increase in obesity.”

One US study found that among 9 to 11-year-olds, 30 to 40 per cent had eating disorder traits, such as being obsessed by their body image, Professor Treasure said. The number who went on to develop an eating disorder was much lower – about 4 per cent in women. An Australian study found a threefold increase in all eating disorders between 1995 and 2005, but some of that increase was due to better identification of sufferers.

Professor Treasure added that there was a link between autism and eating disorders. Shared traits included an inability to see the “bigger picture”, heightened perceptual awareness and rigidity in thinking.

The editorial called for a greater focus on reducing obsessive dieting and poor eating habits among young people. It said: “Although it may take time to change the ‘thin ideal’, we should remember what has been achieved with cigarette smoking.”

Size 0 US measure equivalent to the British size 4, indicating a 32in bust, 22in waist and 33-34in hips

22 waist size in inches of an average eight-year-old in Britain

18.4 body mass index (weight in kilograms divided by height in metres squared) beneath which you are underweight for your height according to the World Health Organisation

12.5 BMI of Ana Carolina Reston, the Brazilian model who died of anorexia in 2006. She was two and a half stone below the recommended minimum weight for her height

30 BMI over which you are classified as obese

Sources: NHS, Times database

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