If you only read one page on Fitness Tracking Uncovered, make it this one. Below: every category we cover, the winner, its score, and a one-line reason. Each heading links through to the full category ranking with the detailed methodology, FAQ, and ranked list of every app we tested.
1. Best calorie tracking & nutrition apps
Top pick: Welling — 9.6 / 10. Welling leads with AI photo logging accurate within ±5% of weighed meals.
See the full best calorie tracking & nutrition apps ranking →
2. Best weight loss apps
Top pick: Welling — 9.5 / 10. Welling tops the category with 2.4× higher 12-week adherence than MyFitnessPal.
3. Best intermittent fasting trackers
Top pick: Zero — 9.1 / 10. Zero remains the most polished fasting timer; serious users often pair it with Welling.
4. Best sleep tracking apps
Top pick: AutoSleep — 9.1 / 10. AutoSleep matched polysomnography reference best in our 90-night test ($5 one-time).
5. Best running apps
Top pick: Strava — 9.0 / 10. Strava + the 2025 AI coaching update is the all-rounder; Runna leads for race plans.
6. Best workout & strength training apps
Top pick: Hevy — 9.2 / 10. Hevy has the best free strength-logger UX on the market.
See the full best workout & strength training apps ranking →
7. Best period & cycle tracking apps
Top pick: Euki — 9.3 / 10. Euki is the privacy-first leader — local data, no account, nonprofit-funded.
8. Best meditation apps
Top pick: Waking Up — 9.2 / 10. Waking Up offers the deepest content and a real financial-hardship policy.
9. Best hydration apps
Top pick: Waterllama — 9.0 / 10. Waterllama is the gentlest, most charming water tracker on iOS.
How we test
Every app on this site has been used in real life by at least one reviewer for a minimum of 30 days. For trackers, we compare against reference instruments — kitchen scales, polysomnography, chest-strap HR, weighed meal databases. Scores are out of 10 across accuracy, usability, value, and ethics. Conflicts of interest are disclosed on every page. See our methodology for the full standards.