The habit · Decision 10 of 14
Tracking and eating disorders
Anybody building a calorie tracker should answer this question clearly, so this page argues against our own product.
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 sure we are Fair , Real, but small, indirect, or thinly measured.
- Surveys find a link. The trials below did not find more symptoms in the people they studied. But they do not prove the app is safe for every user, especially people at higher risk.
- What we do not have
- Access to psychological support. NICE HTG700 requires it of the NHS weight services it assesses, where a team of specialists works together. It is not a rule for every consumer tracker. We are not going to pretend otherwise.
What reviews and experiments found
Surveys do find a link, and that is the first section below. The pooled correlation comes from surveys, which only watch. The other two results are from randomized trials, which test.
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.
Two randomized trials did not detect increased symptoms
Hahn et al. (2021) assigned 200 female students to a month of MyFitnessPal or nothing. There was no statistically significant 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 best summary of where things stand is Moody et al. (2025). The review found a fairly steady link in surveys. The experiments it reviewed did not find the same. It could not say whether tracking causes harm, or which way the link runs. 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).
Two surveys found a stronger link with harm among people tracking to change their weight or shape. But a person’s reason is not a tested way to tell safe use from unsafe use. And the design choices below have not been tested to see if they protect anyone.
What the guidelines actually say
Guidance depends on the setting. A food diary kept with a clinician is not the same as calorie tracking on your own. NICE NG69 includes food records supported by a clinician in some forms 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 applies to certain digital weight-management services being considered for NHS use, where a team of specialists works together. It requires their teams 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
We avoid streaks tied to diet limits as a precaution. Nobody has shown that one badge design harms more than another. The reasoning behind each of those choices, and the two studies on motive that decided the “perfect day” rule, are on the rewards page.