Don't use extreme dieting, fasting or induced vomiting to control your weight; if you want to lose weight, do it on the exercise side
- Top value
- Evidence A
- Buys life
- Free
- Takes minutes
- No willpower
In plain words
People with anorexia nervosa are about 5.9 times as likely to die as others their age. Out of every 1000 people followed for a year, 5.1 die. One in every five of those deaths is a suicide. And dieting is the way in: in a three-year study of students at 44 high schools, girls who dieted severely were 18 times as likely to develop an eating disorder as girls who did not diet. If you want to control your weight, exercise more; don't eat so little that you go hungry.
- Cost
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Free. If anything, you save the money you would have spent on weight-loss products.
- What you get
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36 studies were pooled. The anorexia nervosa group was followed for a total of 166,642 person-years (the years each person was followed, added up). Their standardized mortality ratio was 5.86, meaning their chance of death was about 5.9 times that of people their age. There were 5.1 deaths per 1000 person-years, that is, 5.1 deaths when 1000 people are followed for a year. About 1/5 of the deaths were from suicide. The standardized mortality ratio for bulimia was 1.93 and for other eating disorders 1.92, each about 1.9 times that of people their age. Another study, in 44 high schools in Victoria, Australia, followed students aged 14–15 for 3 years, assessing the same students in 6 waves over the three years. New eating disorders in girls occurred at 21.8 per 1000 person-years, that is, 21.8 new cases when 1000 girls are followed for a year. Girls who dieted severely were at 18 times the risk of those who did not diet, and those who dieted moderately at 5 times. After further adjusting for earlier dieting and psychiatric symptoms, which removes the influence of “had dieted before” and “already had psychiatric symptoms,” BMI (a measure of fatness calculated from weight divided by height squared), amount of exercise and sex no longer predicted a new eating disorder. The authors concluded: “controlling weight through exercise rather than restricting food seems to carry a lower risk of developing an eating disorder among adolescents.”
- Notes
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“Severe dieting” here means cutting food well below what the body needs over a long time, not skipping a meal or a late-night snack. If you have already started vomiting on purpose, blaming yourself after bingeing, or can't stop weighing yourself over and over, see a psychiatrist, or the clinical psychology department of a general hospital. This is an illness with standard treatment, not a matter of willpower. For the relationship between BMI and mortality, see §2.32, which is about long-term weight ranges, not weight-loss methods.
- Evidence grade
- A : Specific numbers from meta-analyses, large cohorts or randomized trials; for law and policy, the statute or official text.
- Sources
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- Arcelus J et al. (2011). Mortality rates in patients with anorexia nervosa and other eating disorders. A meta-analysis of 36 studies. Arch Gen Psychiatry. https://doi.org/10.1001/archgenpsychiatry.2011.74
- Patton GC et al. (1999). Onset of adolescent eating disorders: population based cohort study over 3 years. BMJ. https://doi.org/10.1136/bmj.318.7186.765
Mentioned in
Translated from the Chinese original. Original book, section 28, tip 1. This section is about health and medicines. It is general information, not a substitute for a doctor’s diagnosis or prescription. Content may be out of date and rules differ by place. When you actually deal with an agency, a doctor or a court, follow what local officials, doctors and lawyers tell you. Disclaimer