Diet pills, laxatives cause eating disorders in people in one to three years, says Harvard study

Diet pills and laxatives, used for weight control, could act as a "gateway" that could lead to an eating disorder. Among young women without an eating disorder diagnosis - those who use diet pills and laxatives for weight control - have higher odds of receiving a subsequent first eating disorder diagnosis within one to three years than those who did not report using these products. These are the findings of a new study led by researchers from Harvard T.H. Chan School of Public Health and Boston Children's Hospital.

The team analyzed data from 10,058 women and girls, in the age group of 14 to 36 years, who participated in the US-based Growing Up Today Study (GUTS), from 2001 to 2016.

The researchers found that among participants without an eating disorder, 1.8% of those who used diet pills during the past year reported receiving a first eating disorder diagnosis during the next one to three years. This is compared to 1% of those who did not use the products. 

The analysis also shows that among these participants, 4.2% of those who used laxatives for weight control received a subsequent first eating disorder diagnosis compared to 0.8% of those who did not use these products for weight control. The findings have been published in the American Journal of Public Health (AJPH).

"We have known that diet pills and laxatives, when used for weight control, can be very harmful substances. We wanted to find out if these products could be a gateway behavior that could lead to an eating order diagnosis", says senior author S. Bryn Austin, a Professor in the Department of Social and Behavioral Sciences at Harvard Chan School and director of the Strategic Training Initiative for the Prevention of Eating Disorders (STRIPED). 

Professor Austin says, "Our findings parallel what we have known to be true with tobacco and alcohol: starting harmful substances can set young people on a path to worsening problems, including serious substance abuse disorder."

What the numbers say

Eating disorders represent a significant public health problem. According to a 2018 report by the US Centers for Disease Control and Prevention (CDC), in 2013-16, almost one-half of US adults or 49.1% tried to lose weight within the last year. A higher percentage of younger adults aged 20–39 and middle-aged adults aged 40–59 tried to lose weight, compared with older adults aged 60 and older. 

A higher percentage of women (56.4%) than men (41.7%) tried to lose weight, says the CDC study, based on data collected in the National Health and Nutrition Examination Survey (NHANES) from 2013–16.

According to the National Association of Anorexia Nervosa and Associated Disorders (ANAD), a non-profit organization, at least 30 million people of all ages and genders suffer from an eating disorder in the US, and every 62 minutes at least one person dies as a direct result from an eating disorder.

Further, estimating the prevalence of eating disorders in the US, a 2018 report says that 0.80% of US adults would be affected by anorexia nervosa in their lifetime; 0.28% would be affected by bulimia nervosa, and 0.85% would be affected by binge eating disorder. The estimates were made using a nationally representative sample of 36,309 adults - the largest national sample of US adults ever studied. 

In addition to lifetime estimates, the study - published in Biological Psychiatry - found that 12-month estimates for anorexia nervosa, bulimia nervosa, and binge eating disorder were 0.05%, 0.14%, and 0.44%, respectively.

The study also reported that the eating disorders included in analysis often interfere with normal daily activities and social relationships. 

Experts call for restrictive policies

Healthcare experts do not recommend the use of over-the-counter diet pills or laxatives as a healthy way to manage weight. They can have severe health consequences, including high blood pressure and liver and kidney damage, say experts.

In the current study, the researchers stress that the use of these products for weight control may serve as a "gateway" to further disordered eating practices by "dysregulating normal digestive function and fostering dependence on unhealthy and ineffective coping methods." 

Accordingly, based on their findings, the researchers have called for policies that restrict access to these products, including banning the sale of diet pills to minors. 

"Our findings are a wake-up call about the serious risks of these products. Instagram took a step in the right direction recently by banning ads to minors for over-the-counter diet pills and 'detox' teas, which are often laxatives", says first author Jordan Levinson, clinical research assistant, Division of Adolescent Medicine, Boston Children's Hospital. 

Levinson says, "It is time for retailers and policymakers to take the dangers of these products seriously and take steps to protect youth."