Decision 5 of 10

Tracking and eating disorders

Anybody building a calorie tracker should answer this question clearly, so this page argues against our own product.

Written and maintained by Mattias Geniar. Last updated .

What the app does
No streak on the sugar limit, no celebration for staying under a limit, no “perfect day”, and it shows what is left rather than counting upward.
How much we believe it
The link is real in surveys and has never shown up in an experiment. Nobody knows which causes which. We designed for the worst case anyway.
What we do not have
Access to psychological support, which is what NICE HTG700 asks of a commercial weight-management service. We are not going to pretend otherwise.

The link is real in surveys

Levinson et al. (2017) surveyed 105 adults who had recently finished eating-disorder treatment. The authors say clearly that the answers look back in time and cannot show cause.

What people leaving eating-disorder treatment said about calorie apps 105 adults, surveyed after discharge. Each bar is a share of the group above it.
Had used MyFitnessPal 74%

Of all 105 respondents

Of those, said it contributed at least somewhat 73%

To their eating disorder

Of those, said “very much” 30%

The strongest answer offered

0 100% of the group
Looking back, self-reported, and from a group chosen because they had had an eating disorder. It is the strongest version of the case against this kind of app. It is also the kind of evidence that cannot tell you whether the app was a cause, a symptom, or a tool somebody picked up.

Every study that has actually tested tracking has found no effect

Hahn et al. (2021) assigned 200 female students to a month of MyFitnessPal or nothing. There was no effect on eating-disorder symptoms (β = −0.04, p = 0.17). The students had been screened as low risk, though. Jospe et al. (2018) followed 250 adults for twelve months and found no differences (all p ≥ 0.164). In that group, 53.6% had binge eating at the start.

The pooled estimate, across everything that has measured it Correlation between calorie tracking and disordered eating, 9 studies, 13,507 people.
no difference
Tracking against disordered eating, pooled r = 0.13

Roth et al. 2024, 9 studies, 13,507 people, 95% CI −0.02 to 0.28

r = −0.10 r = +0.36
Drawn in grey rather than in this page's colour because the interval crosses zero: p = 0.08, not statistically significant (Roth et al., 2024). That does not mean tracking is safe. It means the question is still open, on a sample large enough that it should not be.

The best summary of where things stand is Moody et al. (2025). Surveys show a fairly consistent link, “however, this association was not replicated in experimental research.” It is “currently not possible to conclude if they increase disordered eating, or the direction of this relationship.” Studies that follow people over time point both ways. In one group, tracking predicted disordered eating later. In another, behaviour like purging or over-exercising predicted tracking later (O'Loughlin et al., 2023, adjusted OR 1.7).

What does reliably separate harm from no harm is why somebody is tracking. Two separate studies found that tracking to control weight and shape is linked with harm, and tracking for health and fitness is not.

What the guidelines actually say

No guideline we could find bans calorie tracking. The pattern is to screen people and adjust, not to avoid it. NICE NG69 actually prescribes keeping a record of what you eat as part of eating-disorder treatment. The 2023 AAP guideline notes that eating disorders and other conditions “may preclude the use of certain tools that require intensive tracking.” The clearest statement about apps like ours is NICE HTG700. It requires commercial weight-management services to have access to psychological support “to reduce the risk of harm, including from disordered eating.”

Snapkin has no such support, and we are not going to pretend otherwise. If you have or have had an eating disorder, please talk to a clinician before using this or any tracker.

What that changed in the app

The uncertainty above is not a reason to design as if the answer were “no harm”. It is a reason to design as if the answer were “harm”. Doing that costs a few interface decisions. Being wrong the other way costs somebody their health.

What the app does

  • Shows what is left of your day rather than counting upward
  • Rewards logging, including on a day that went over
  • Treats the calorie target as a range with a minimum as well as a maximum
  • Lets you correct any number it produced

What it will not do

  • No streak on the added sugar limit
  • No celebration for staying under a limit
  • Nothing called “perfect”
  • No reward that can be earned faster by eating less

A limit on something with a streak attached is the design that does the most harm to the people most likely to be counting. The reasoning behind each of those choices, and the two studies on motive that decided the “perfect day” rule, are on the rewards page.