Are smartphones linked to eating disorders in kids? New study

Researchers following 8,957 US children found that kids who owned a smartphone at 12 reported more eating disorder symptoms at 12 and again at 14, according to Stony Brook Medicine's summary of the paper. So are smartphones linked to eating disorders in kids? The honest answer is that they're linked, and nobody has shown that the phone is the cause.

Most parents met this study through headlines like CNN's "12-year-olds with smartphones are more likely to develop eating disorders by 14". If you've just handed your 11-year-old a phone, that's an unsettling thing to read. The useful part is that the likely reasons behind the link point to things you can change without taking the phone away: what's in the feed, where the phone sleeps, and how often you talk about what your child sees.

What the researchers measured in 8,957 children

The study, published in JAMA Network Open, used data from the ABCD Study, a large US project that follows children through adolescence. The researchers looked at whether each child owned a smartphone at 12, then compared eating disorder symptoms at 12 and two years later at 14.

That matters for reading the results. Phone owners were the clear majority, so the comparison group was the minority of 12-year-olds without one. The four symptoms tracked were:

• Binge eating
• Behaviours used to prevent weight gain
• Worry about gaining weight
• Tying self-worth to weight

Phone owners reported more binge eating at both 12 and 14

At 12, children with phones were more likely to report binge eating, tying their self-worth to their weight, and at least one eating disorder symptom. By 14, the list had grown: binge eating, behaviours to prevent weight gain, weight-based self-worth, and at least one symptom, per Stony Brook Medicine.

One symptom didn't show up as different at either age in that summary: worry about gaining weight. I also haven't been able to check the exact size of the differences against the full paper, so I'm not going to quote odds ratios. Treat the direction of the finding as solid and the size as an open question for now.

Are smartphones linked to eating disorders in kids, or is something else going on?

This is an association study, and the authors say so. Families who hand over a phone at 12 may differ from families who wait, in income, routines, supervision or a dozen other ways, and any of those could play a part.

Symptoms are also different from diagnoses. A child who reports an episode of binge eating hasn't been diagnosed with an eating disorder. And the sample is American, so it may not map neatly onto children elsewhere.

Still, the result fits earlier work. Previous analyses of the same ABCD data linked each extra hour of screen time and social media use with higher odds of compensatory behaviours, binge eating symptoms and weight-related self-worth (Eating and Weight Disorders). That's also correlational, but two findings pointing the same way are harder to wave off than one. If you're still weighing timing, I've covered what age a child should get a smartphone separately.

Five reasons a phone might feed body worries

The clinicians writing for Stony Brook Medicine list several plausible explanations. These are informed guesses, not things this study tested:

1. Appearance-focused and idealised images, seen over and over
2. Constant comparison with peers and strangers
3. Content and communities that promote disordered eating
4. Lost sleep and disrupted routines, including meals
5. The private, personalised nature of a phone, where a feed learns what a child lingers on and nobody else sees it

Timing adds to it. Early adolescence is already a higher-risk period for eating disorders, so a first phone often arrives right when a child is most open to these pressures. Notice that most of the list is about what the phone delivers and what it displaces, rather than the device itself.

Small effects across 2.8 million children still count

A separate JAMA Pediatrics umbrella review pooled 23 meta-analyses covering more than 2.8 million children and teens in 64 countries. More screen use went with lower academic and language scores and more emotional and peer problems. Social media in particular was tied to anxiety, depression and withdrawal.

Most of those associations were small, and they varied by type of use and age. I went through the general picture in is all screen time bad for kids. One of the review's authors put the size question well:

Changes in mood, sleep or eating are a reason to check in

Stony Brook's clinicians suggest watching for shifts in mood, sleep, eating habits, school performance and friendships. None of these proves the phone is to blame. They are a signal to talk, and if you're worried about your child's eating or weight talk, to book an appointment with their paediatrician.

Six changes that don't involve confiscating the phone

Each of these ties back to one of the explanations above. None needs a dramatic phone ban.

1. 01
   Look at the feeds, not just the hours

   the review found effects depended on type of use, and appearance-focused feeds are the main concern.

2. 02
   Keep the useful parts

   messages, maps and school tools carry little of the comparison risk and plenty of the reasons you gave the phone.

3. 03
   Charge it outside the bedroom

   sleep and routines are on the list of likely reasons, and a phone on the kitchen counter can't scroll at midnight.

4. 04
   Protect meals and offline time

   notice what the phone is quietly replacing, whether that's dinner, sport or seeing friends.

5. 05
   Talk about what they see

   name idealised images, the pull to compare, and accounts that push dieting, so your child can spot them too.

6. 06
   Change things gradually

   Stony Brook notes that sudden changes in access affect some children differently, especially those used to constant access, so explain each step.

On the bedroom point, the same logic applies at any age. I've written more about how scrolling before bed affects sleep if you want the detail.