Can Eating Disorders Delay Or Stunt Your Growth?

No two teenagers grow in exactly the same pattern or at exactly the same rate. Even unusually diminutive teenagers may be growing to their full potential dictated by their genes. But when height and weight of a still-developing adolescent rank in the fifth percentile or lower compared to their peers, doctors look for medical explanations for delayed or stunted growth.

Just how severely does anorexia nervosa stunt growth?

When researchers consider the effects of anorexia nervosa on growth during adolescence, they take into account that there is a wide range of adult heights among people who have eating disorders as well as among people who don’t. To estimate the influence of anorexia on growth during adolescence, they look at the "average" height of a large number of people who had anorexia as children and adolescents compared to the "average" height of a large number who did not.

Research finds that:

• People with anorexia who develop the condition before puberty have the most severe stunting of growth.
• Most teens who are hospitalized for anorexia begin to gain height as soon as they return to more nearly normal eating habits, but they never quite catch up to their expected height.
• On "average", adults who recovered from anorexia they had as children or teens are shorter than adults who did not have anorexia.
• The research does not point to a way of calculating the exact number of inches or centimeters of height lost due to anorexia for an individual. All the research can tell us is what the general trends are. However, a "good guess" based on the statistical data is that most teenage girls who recover from anorexia reach a final height 2 to 3 cm (about 1 to 1-1/2 inches) less than their genetic potential, and most teenage boys who recover from anorexia reach a final height 4 to 5 cm (about 2 to 3 inches) less than their genetic potential.

Sometimes teens who have anorexia nervosa have a longer opportunity to grow taller. Greater height is possible as long as the growth plates in the bones (called epiphyses) are not fused. The grown plates stay open until sex hormones stimulate their fusion. Teens who have anorexia produce smaller quantities of sex hormones, so the growth plates stay open longer, so they have more opportunities to grow taller. However, having anorexia before puberty cancels out this effect.

Some teenagers, both male and female, who are eventually discovered to have anorexia nervosa stop growing taller as much as two years before their doctors discover their disease. Now most doctors will suspect and test for anorexia in any child or teenager who fails to grow taller as expected.

What about stunted growth in bulimia nervosa?

Not all bulimics are thin.Teens who live with bulimia generally suffer less severe stunting of growth than teens who live with anorexia. Bulimics tend to purge their nutrients, but they also consume more nutrients than teens who have anorexia. Studies have not found a definitive loss of stature that occurs across all cases of bulimia.

However, there is a relationship between bulimia and future height in bulimics who are below normal weight. In these people who live with bulimia, weight suppression predicts future height and weight. It’s not the weight at the time of diagnosis, or the highest-ever weight, or the lowest-ever weight that predicts future stature. It’s whether the bulimic can both recover from the disease and still continue to gain weight as predicted for age and height. Bulimics who can’t gain any weight don’t gain expected height.

Binge-eating disorder is a special case

Teenagers who present with binge-eating disorder may or may not be obese. They do not have any special risk for failure to develop their fullest expected height and weight. However, "over treating" a binge eating disorder can result in suppression of growth from which the teenager will not have a chance to recover.

The bottom line on eating disorders and physical growth during adolescence