Study analysis · European Eating Disorders Review · 2025

Fitness trackers aren't causing eating disorders—but they're drawing in people who already have them.

People who use fitness apps tend to have stricter eating habits, but when you give someone a tracker, it doesn’t make them obsessed—so the problem isn’t the app, it’s who’s using it.

Reading level
Low certainty
Level 2a · Systematic review of cohort studiesAssociation, not causationNo causal claims

Overview

What the study found

The study in plain English — the bottom line, every takeaway we extracted, and what to do with them.

In simple terms

This study looked at lots of other studies and found that people who use fitness apps often also have unhealthy thoughts about food or exercise — but it doesn't prove the apps cause those thoughts. It could be that people who already worry about their body are more likely to use these apps. So we know they go together, but we don't know which came first.

What’s the bottom line?

People who use fitness and diet apps often report more obsessive eating and exercise habits—but experiments where people are told to use these apps don’t show those habits getting worse.

How strong is this study?

The researchers did a good job searching for all the studies and checking them carefully, but most of the studies they found were just surveys asking people questions at one point in time. That's like taking a photo — it doesn't show what happened before or after. So while the review is well-done, the original studies aren't strong enough to say for sure if the apps are the problem.

Reporting

40 / 100

  • COI disclosure+40/40
  • Data availabilitydata not shared
  • Code availabilitycode not shared
Methodology

0 / 100

  • Randomizationnot randomized
  • Blindingblinding unclear
  • Control groupno control group
  • Sample sizeno sample size reported
  • Follow-upno follow-up reported
Publication

100 / 100

Statistical

100 / 100

  • P-values+15/15
  • Effect size+20/20
  • Confidence intervals+15/15
  • Pre-registration+15/15

Each component is scored out of 100 and then capped by the study design — a case series cannot reach the ceiling a randomised trial can, however well it is reported.

Where it sits

RCT reviews

Max 100

Randomized Trials

Max 90

Reviews of Cohort Studies

Max 85

Cohort Studies

Max 72

Reviews of Case-Control Studies

Max 63

Case-Control Studies

Max 58

Cross-Sectional & Case Series

Max 50

Expert Opinion

Max 5
StrongerWeaker
Reviews of Cohort Studies
Level 2a
53

53 / 100

Probability of being correct

Systematic reviews and meta-analyses of cohort studies. They sit above a single cohort study but below a single randomized trial, because the underlying evidence is still observational.

This design cannot establish causation — the findings describe an association, not a cause. This study is a systematic review of mostly observational (cross-sectional and longitudinal) studies, with only a few experimental studies included. The observational studies show association but cannot prove direction or causation. Experimental studies were limited in number, sample size, and quality, and did not consistently show causal effects. The review itself concludes that causation cannot be determined.

No Conflicts

No conflicts of interest identified

No conflicts of interest or funding disclosures were reported in the study text; no industry ties or funder involvement were identified.

The study is a systematic review with no declared funding, no author affiliations with industry, and no evidence of funder influence. The protocol was registered on Open Science Framework and PRISMA guidelines were followed, suggesting methodological rigor. However, absence of a COI or funding statement does not confirm absence of conflicts — it only indicates lack of disclosure.

Key takeaways

  1. 01

    In 27 studies, tracker users showed higher levels of dietary restraint, excessive exercise, and muscle obsession—but when people were randomly assigned to use trackers for weeks, no increase in these behaviors occurred.

  2. 02

    This suggests tracker use may attract people already worried about weight or shape, rather than causing those worries to start.

Surprising findings

  • Experimental studies found no increase in disordered eating after controlled tracker use—even in people who didn’t have eating disorders before.Everyone assumes tech causes harm, but when researchers forced people to use trackers for weeks, their behaviors didn’t worsen—suggesting the correlation is about selection bias, not technology-induced harm.
  • One RCT found participants using Fitbits for 10 days reported significantly lower dietary restraint than non-users.This directly contradicts the idea that tracking increases restriction—it suggests tracking might, in some contexts, reduce rigid thinking about food.
  • Only one longitudinal study found tracker use in adolescence predicted increased disordered eating in early adulthood—but no experimental study has replicated this over time.Long-term harm is assumed, but we have zero controlled evidence that trackers cause worsening over time—only observational correlations that could reflect pre-existing vulnerability.

Practical takeaways

If you use a fitness tracker, ask yourself: 'Am I tracking to feel healthier—or to control my body?' If it’s the latter, consider pausing or switching to non-numerical goals.

This applies mainly to people with a history of body image issues or disordered eating; for others, trackers may still support healthy habits without harm.

medium confidence

Clinicians should routinely ask patients with eating disorders: 'Do you use fitness or diet apps? How and why?' This can reveal hidden triggers.

Don’t assume all tracking is bad—some patients use apps successfully in recovery under professional guidance.

high confidence

Parents of teens should talk about tracker use—not ban it. Focus on why they’re using it and whether it’s causing stress or obsession.

Most teens use trackers safely; risk is concentrated in those already vulnerable to body image concerns.

medium confidence

Why this study matters

The Correlation That Isn't Causation

Of 27 studies, 17 cross-sectional ones found consistent links between fitness/diet tracker use and disordered eating behaviors—especially dietary restraint, excessive exercise, and muscle obsession—particularly in young women. But in the 3 randomized controlled trials and 5 quasi-experiments, no significant increase in these behaviors occurred after controlled tracker use.

This flips the narrative: instead of blaming apps for creating eating disorders, the data suggests people already struggling with body image are the ones drawn to tracking—making tech a mirror, not a trigger.

The 83% Who Blame Their App

In one study of people with diagnosed eating disorders, 83% said MyFitnessPal 'at least somewhat contributed' to their condition, and 30% said it 'very much contributed'—especially those using it for weight/shape goals, not health.

This reveals a dangerous feedback loop: people with existing disorders use trackers to reinforce control, and the app’s gamified feedback makes it harder to break the cycle—even if the app didn’t cause the disorder.

No Link to Binge Eating—Here’s Why

Contrary to fears, 5 observational studies found no consistent link between tracker use and binge eating. One RCT even found participants using Fitbits binged less than non-users.

This challenges the assumption that all tracking is harmful—it suggests for some, structure and accountability may actually reduce binge cycles, especially if motivation is health-focused, not weight-focused.

The Muscle-Obsession Gap

Two studies found tracker users were more likely to engage in disordered muscle-building behaviors—like steroid use or extreme dieting—but no experimental studies have tested this. The link was strongest when users tracked for body shape, not fitness.

While everyone talks about calorie counting, few notice that fitness trackers may be fueling a silent epidemic of muscle dysmorphia in young men—especially with apps that track protein intake and gym reps.

Want the whole report?

Detailed mode opens the full scientific breakdown — every score component, the methodology, conflicts of interest, the evidence analysis behind each claim, and the raw study data.