How to spot an eating disorder in a teenager

Eating disorders in teenagers are more common than most families expect, and the biggest barrier to catching them early is a set of wrong assumptions — that a young person must be visibly underweight, that it only affects girls, or that it is a phase. A large pooled analysis suggests that roughly one in five children and adolescents screens positive for disordered eating, and the signs that matter most are about behaviour and preoccupation, not the number on the scales [s1]. The reason to act early is simple: these are serious illnesses, and earlier help gives a better chance of recovery.

How common it is

The best recent estimate comes from a systematic review and meta-analysis in JAMA Pediatrics, which pooled 32 studies covering 63,181 participants from 16 countries [s1]. Overall, 22.36% of children and adolescents showed disordered eating on screening (95% confidence interval 18.84% to 26.09%) [s1]. That is not the same as saying a fifth have a diagnosed eating disorder — a positive screen flags concern that needs assessment, not a diagnosis — but it shows how widespread the warning signs are.

The pattern by sex and age is clear. Girls were significantly more likely to screen positive, at 30.03% (95% CI 25.61% to 34.65%), than boys, at 16.98% (95% CI 13.46% to 20.81%) [s1]. Disordered eating also became more common with increasing age and with higher body mass index [s1]. That last point is important for parents and clinicians alike: eating disorders occur across the weight spectrum, including in young people who are not underweight and may even be praised for "eating healthily."

What the screening question set looks like

The tool behind most of these figures is the SCOFF questionnaire, a five-item screen designed in 1999 to be quick enough for everyday use [s1] [s2]. It asks, in plain terms, about making oneself sick because of feeling uncomfortably full, about loss of control over eating, about recent weight loss, about believing oneself to be fat when others disagree, and about food dominating life [s2]. It was created as a simple, memorable prompt for non-specialists, not as a diagnostic test [s2].

For families, the value of knowing the questions is not to self-diagnose but to recognise the territory: recurrent vomiting, secrecy or rigidity around meals, distorted body image, and eating that has come to dominate a young person's thinking are the signals that warrant a conversation and a professional assessment.

What good practice says

National guidance is explicit that screening should not hinge on weight. NICE advises that professionals not use single measures such as body mass index, or a single screening question, to decide whether to offer treatment, and warns against assuming a young person is well simply because their weight looks normal [s3]. Instead it emphasises taking any concern seriously, assessing physical and psychological health together, and referring promptly to a specialist eating-disorder service [s3].

That framing matters because the most dangerous myth is the visible-thinness test. A teenager can be seriously unwell — physically and psychologically — while sitting at an unremarkable weight, and waiting for obvious wasting is waiting too long [s3].

How to read this without overreaching

The evidence supports vigilance rather than alarm: disordered eating is common, weight is an unreliable guide, girls are affected more but boys are far from exempt, and the right response to worry is assessment, not a home verdict [s1] [s3]. Screening tools point toward a conversation; they do not replace one.

The limits are real. The 22% figure reflects positive screens in community samples, with very high statistical heterogeneity between studies, so it should be read as a signal of scale, not a precise diagnosis rate [s1]. The SCOFF was validated decades ago and performs differently across settings, which is exactly why guidelines caution against leaning on any single question [s2] [s3].

This article is informational and is not medical advice. If you are worried that a child or teenager may have an eating disorder, contact a GP, who can assess and refer to a specialist service; eating disorders are treatable, and early help improves outcomes. If there is any concern about immediate physical or mental health risk, seek urgent medical care or contact a local crisis line.