Unhealthy Dieting Trends in US Teens

by Ashley Jordan Ferira, PhD, RDN

There is a paradox occurring in American youth: obesity and dieting. National statistics confirm that pediatric overweight and obesity rates are high, steadily rising over the past few decades.¹ In fact, over 20% of the 12-19 age group in the US are obese, with higher prevalence in Hispanics and blacks.¹ Actual weight and the teenager’s perception of their weight can be incongruent. Furthermore, weight status misperception drives intent for weight change.³ American youth are engaging in high rates of weight loss attempts (1 in 2 high school students)⁴ and unhealthy dieting behaviors (UDBs).²

A BMC Public Health study examined UDB prevalence and trends in US adolescents (n=113,542) over a 14-year period (from 1999-2013) using the nationally representative, cross-sectional, school-based Youth Risk Behavior Surveillance System (YRBSS) survey, which gathers self-report health data in American high schoolers (public and private schools; grades 9-12; all 50 states and DC).² The 4 race categories included in this data analysis were white, black, Hispanic, and “all other races”.²

Along with weight status (i.e., BMI-for-age percentiles calculated from self-report height and weight), weight change intentions were assessed. During the 1999-2013 period, 59-63% of girls and 26-33% of boys wanted to lose weight, while 6-10% of girls and 26-30% of boys wanted to gain weight.² The teens desiring weight loss had the highest odds of engaging in UDBs, which included:²

• Fasting for ≥24 hours
• Taking diet pills, powders, or liquids (PPLs) without doctor’s advice
• Vomiting or taking laxatives to lose weight or keep from gaining weight

Major observations:²

• Teens overestimating their weight status: 15.9% of girls; 6.1% of boys
• Teens underestimating their weight status: 25.0% of girls; 40.2% of boys
• Performed at least 1 UDB in the last 30 days to lose or maintain weight: 22.7% of girls; 10.1% of boys
• Compared to normal weight teens, those who were underweight, overweight, or obese were more likely to have engaged in a UDB in the last 30 days
• Teens with overweight or obese status had a higher odds of displaying UDBs
• Overestimating one’s weight status was the strongest determinant of UDBs

Racial differences:²

• Boys: Compared to whites, blacks were more likely to engage in all UDBs, except taking diet PPLs. All non-white races participated in more vomiting/laxatives than whites, and fasting was more common in “all other races” than whites.
• Girls: Compared to whites, blacks and Hispanics were less likely to take diet PPLs

Except for a slight decrease in diet PPL use, UDB prevalence and associated racial disparities persisted from 1999 to 2013 in US teens.² UDBs may exacerbate weight gain in overweight/obese adolescents and worsen weight loss in underweight teens; furthermore, UDBs are a risk factor for eating disorders.⁵

Why is this Clinically Relevant?

• Awareness of the pediatric overweight and obesity problem is high, but practitioners should also be cognizant of the high UDB prevalence in US teens, which is twice as common in females² and can precipitate eating disorders⁵
• Clinicians should aim to partner with pediatric patients and their families to promote healthful dietary patterns and regular physical activity, while also educating about the dangers of UDB practices and their ineffectiveness in achieving a healthy weight over the long term

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 Citations

1. Hales CM, Carroll MD, Fryar CD, Ogden CL. Prevalence of obesity among adults and youth: United States, 2015–2016. NCHS data brief, no 288. Hyattsville, MD: National Center for Health Statistics. 2017.
2. Chin SNM, Laverty AA, Filippidis FT. Trends and correlates of unhealthy dieting behaviors among adolescents in the United States, 1999-2013. BMC Public Health. 2018;18(1):439.
3. Khambalia A, Hardy LL, Bauman A. Accuracy of weight perception, lifestyle behaviors and psychological distress among overweight and obese adolescents. J Paediatr Child Health. 2012;48(3):220-227.
4. Grunbaum JA, Kann L, Kinchen S, et al. Youth risk behavior surveillance-United States, 2003. Morb Mortal Wkly Rep Surveill Summ. 2004;53(2):1-96.
5. Patton GC, Selzer R, Coffey C, Carlin JB, Wolfe R. Onset of adolescent eating disorders: population based cohort study over 3 years. BMJ. 1999;318(7186):765-768.