Eating disorders, whether they be the starvation regimes of anorexia and bulimia or the compulsive eating which leads to overweight and in some cases morbid obesity, are on the rise. Medical research has, frustratingly, not kept pace with the increase. For years the theory that people who suffer from these problems are mentally unstable, slothful or undisciplined has prevailed so much so that it is now difficult to find any practitioner who will acknowledge a possible biological basis for these disorders.

No one would deny the psychological component of eating disorders, but as a total diagnosis it is unsatisfactory. For instance, family background is often cited as a risk factor in eating disorders, with those coming from abusive or dysfunctional families having the highest risk. But we have to ask: how is it that there are women who come from abusive or dysfunctional families who do not develop into anorexics or turn to compulsive eating as a way of dealing with unresolved problems?

To the minds of many clinicians, "fat phobia" is still the central defining characteristic of anorexia and bulimia (Soc Sci Med, 1995; 15: 25-36; Int J Eat Dis, 1996; 1594: 317-34). But entrenchment in this attitude hasn't moved us much closer to a cure. In one study, only 29 per cent of treated anorexics had shown significant recovery 20 years later, and approximately 15 per cent died from suicide or starvation (Br J Psych, 1991; 58: 495-502).

Equally, since there is not yet a medical cure for obesity, it is often easier to explain it away by blaming some weakness in the individual. Yet we know that simplistic solutions such as eating less and/or exercising more do not always produce results. Some theorists believe that exercise contributes little to weight loss (AM J Clin Nutri, 1993; 57: 127-34). This is because physical activity normally only accounts for a small proportion of an individual's total energy expenditure. About 80 per cent of a person's energy is used to maintain the resting physiological processes of the body and to digest food (Am J Clin Nutr, 1992; 55: 533S-7S).

At the same time, individuals can vary enormously in the way they can dissipate energy through diet induced thermogenesis (fat burning). When one study looked at pairs matched for sex, weight, age, height and activity level, it found that it was not uncommon for one member of a pair to be consuming twice as many calories as the other member without gaining more weight than the other (Br J Nutri, 1061; 15: 1-9).

It's time to take a wider view.

Slimming Disorders

Anorexia and bulimia affect nearly 1.2 million adolescent and young adults in the US, but only 5-10 per cent of these are males. In the UK, an estimated 1 per cent of teenagers are anorexic and 3 per cent, bulimic. Estimates of mortality can range from 1 to 5 per cent and are usually due to kidney failure, heart attack, dehydration or suicide (Nurse Pract, 1990; 15: 12-18, 21).

As stated before, recovery rates are not very encouraging. Although in one study over six years, 77 per cent of patients were classified as "recovered", at the end of the study period the total risk of relapse among recovered anorexics was 48 per cent though none had more than one relapse. More worrying, the mortality rate was 17.8 times higher than expected, with bulimic patients having twice the risk of premature death as anorexics (Acta Psychi Scand, 1993; 19: 437-44).