Don't Diet, Exercise! An Important Message for Teens

Source: British Medical Journal, 318, 20 March

More and more teens in the US are overweight. Many concerned parents encourage their teens to lose weight for the sake of their long term health. However, a recent study indicates that encouraging young adults, especially girls, to diet may lead to the onset of eating disorders such as bulimia and anorexia — potentially very serious consequences. The better solution to weight control, the researchers concluded, is regular exercise.

The study
Surveys have shown that as many as 5% of adolescent women suffer from anorexia nervosa and 1% from bulimia nervosa and that these eating disorders most commonly emerge in mid-adolescence, developing into full syndromes later. This study was conducted using nearly 2,000 students, initially ages 14-15 years from secondary schools in the state of Victoria, Australia. After taking initial measurements of height and weight, they followed the progress of these students over a three year period, paying particular attention to the following:

1. Dieting habits
Dieting levels were categorized as moderate or severe and three dieting strategies were measured; calorie counting, reducing food quantities at meals, and skipping meals.

2. Exercise
Two types of exercise frequency were measured; daily participation in sports and formal exercise routines.

3. Psychiatric considerations
Mental health status was evaluated with a computerized form of the revised clinical interview schedule, which is a questionnaire for assessing common symptoms of psychiatric disorders.

What they found
The Australian researchers found that 8% of 15 year old girls studied dieted at severe levels and that these girls were 18 times more likely to develop eating disorders within 6 months than the teenagers who didn?t diet at all. Over the next 12 months these girls showed a 1 in 5 chance of developing a new eating disorder.

The study further demonstrated that another 60% of the subject girls dieted at moderate levels, and, even at this level, these girls were 5 times more likely to develop a new eating disorder in 6 months than the non-dieting control group. The percentage of risk jumped to 40% over a year.

In contrast, fewer than 1 in 500 of the students in the non-dieting control group developed any type of eating disorder within a year.

Psychiatric problems are an important factor in eating disorders
The study also showed that the teen's mental state had a strong influence upon their risk of developing an eating disorder. Those subjects who had experienced some kind of mental health problem had more than six times the risk of developing a new eating disorder. Female subjects in the severe dieting group with high levels of psychiatric problems had a greater than 1 in 4 chance of developing a serious eating disorder within 12 months.

Teenage girls were more likely to develop eating disorders
The study found that the onset of adolescent eating disorders was much more prevalent with the girls in the study than the boys. Not surprisingly, researchers concluded the probable cause of the predominance of eating disorders in females to be their tendency to start dieting at a younger age than their male counterparts. Young girls are much more concerned with weight and image than boys of the same age and, thus, the female subjects suffered psychiatric concerns at a higher rate which added to their susceptibility to eating disorders.

Exercise is the better solution
This study takes issue with the recent debates that tend to blame the emphasis on sports in schools — especially sports such as gymnastics that require thinness — as the culprit in the increase in the onset of adolescent eating disorders. Instead, these researchers conclude that daily participation in sports did not raise risks above those already associated with dieting. Their conclusion and recommendation, in fact, is that if you have a child with a weight problem, find some type of sport they will enjoy to take their minds off of dieting as a solution. Promotion of exercise rather than restriction of dietary intake, emphasize these researchers, may prove less of a risk in the development of eating disorders.

Summary
Encouraging sport and exercise in young adults is a great way to start them out towards a lifetime of healthy living. It is important to make sure your children know how to eat a healthy diet, but putting them under pressure to diet can have serious consequences.