Should You Build a Water, Calorie or Fitness Tracking App in 2026? An Indie Developer's Honest Answer
Published: September 14, 2026 · Furkan Mert Fındıklı · 9 min read
Short answer: For most founders: not a general-purpose one. Calorie counting, water tracking and workout tracking are three of the most crowded corners of Health & Fitness. MyFitnessPal serves more than 200 million users and bought Cal AI, the breakout AI photo calorie app (deal closed December 2025). Strava raised money at a $2.2 billion valuation with more than 150 million registered users. Samsung Health gives food, water and exercise logging away for free. Even the all-in-one idea — water, calories and GPS workouts in one app that feed each other — is already taken by apps like Suu, which I have been building since 2024. A new tracker only makes sense for a specific audience that all of these serve badly.
Every few weeks someone asks me a version of the same question: “I want to make a water reminder app” or “I have an idea for an AI calorie counter — is it worth it?” It's a fair question. From the outside a tracker looks simple: a counter, a goal, a reminder, maybe a chart.
I learned how misleading that simplicity is by building one. Suu started as a water tracker and grew into an app where hydration, calories and GPS workouts update each other. Along the way I hit every wall a newcomer in this category hits — and I watched the incumbents get bigger, not smaller.
So here is the market as it actually looks in 2026, with sources, and the questions I'd want answered before writing a single line of code.
Who already owns each tracking category
| What a new app must match | MyFitnessPal | Strava | WaterMinder | Suu |
|---|---|---|---|---|
| Calorie & macro logging | ✓ 20M+ food database | ✗ | ✗ | ✓ Photo, voice or text |
| AI photo meal logging | ✓ Meal Scan (Premium) · owns Cal AI | ✗ | ✗ | ✓ Premium |
| Water tracking | Basic water log | ✗ | ✓ Specialist | ✓ 91 beverages, adaptive goal |
| Live GPS workout with route map | Via connected apps | ✓ Best in class | ✗ | ✓ About 50 activities |
| Scale | 200M+ users | 150M+ registered users | Not disclosed | 4.9★ on Google Play (2,847 ratings) |
| Money behind it | $345M acquisition (2020) | $2.2B valuation (2025) | Not disclosed | Indie, on the stores since 2024 |
| Languages a newcomer must localize for | Many | Many | Several | 7, including right-to-left Arabic |
1. Every category already has a winner — and the winners keep buying
Calorie tracking is the clearest case. Francisco Partners bought MyFitnessPal for $345 million in 2020, when it already served more than 200 million users.1 When a newcomer did break through — Cal AI, built by two high-school friends, passed 15 million downloads and about $30 million in annual revenue in under two years — MyFitnessPal acquired it.2 Yazio, Lifesum and Cronometer each hold their own slice: diet plans, habit coaching, micronutrients.
Workout tracking is the same story. Strava raised new funding at a $2.2 billion valuation in 2025 with more than 150 million registered users,3 and bought the AI training apps Runna and The Breakaway that same year. Apple, Samsung, Google and Nike all ship their own workout apps.
Water tracking looks like the easy gap, but it's where apps are most interchangeable: WaterMinder, Waterllama, Plant Nanny and Hydro Coach have spent years polishing reminders, widgets and watch apps.
Capital is concentrating, too. Crunchbase counted $1.26 billion raised by fitness startups in 2024 — the lowest in five years, down from $6.27 billion in 2021.3 Less money goes to more-of-the-same apps; more goes to the few that already lead.
2. “Add AI” stopped being a differentiator
In 2023 an AI photo calorie counter felt new. In 2026 the category leader has its own Meal Scan feature8 and owns the most successful photo-first app. When the leader owns the feature, the feature is no longer your edge. Suu does both photo and voice logging — you can photograph a plate or just say “a bowl of lentil soup and a glass of ayran” — but I don't pretend that alone makes an app special.
Every photo analysis also costs money: one cloud vision-model call per meal. Your free tier has to be generous enough to compete with apps that already have enormous free user bases, and strict enough not to burn your runway. That's why Suu gives 3 free AI analyses a day and keeps photo recognition in Premium.
3. The platforms give the basics away for free
Before a user ever opens the App Store, their phone already tracks something. Samsung Health lets Galaxy owners log what they eat and how many calories it contains, track water against a daily goal, and review their workouts.7 Apple Health stores water and nutrition data, and Google Health Connect does the same on Android. A new tracker isn't competing with nothing — it's competing with “good enough and already installed.”
Apple is explicit about crowded categories. App Store Review Guideline 4.3(b) says: “Don't submit apps that are indistinguishable from what's already widely available.” For well-established app types such as flashlights and simple timers, Apple says it will not accept new submissions unless they “offer a meaningfully different or improved experience.”6 Water trackers aren't on that list — but a generic counter carries exactly that risk.
4. The hidden work behind a “simple” tracker
This is the part I underestimated most. A tracker people trust with their health needs far more than a counter:
- Health data is legally special. Under the GDPR (Article 9)9 and Turkey's KVKK, health data is a special category with stricter rules. Apple's Guideline 5.1.3 bans using HealthKit data for advertising and storing personal health information in iCloud.6
- Two-way health sync on two platforms. Suu reads and writes both Apple HealthKit and Google Health Connect — two data models, two permission flows, two sets of edge cases.
- Nutrition science, not just numbers. Coffee doesn't hydrate like water. Suu models 91 beverages, and meals high in protein and sodium raise the day's water need.
- GPS workouts are a product of their own. Background location permissions, start/pause/finish, a route drawn on the map, pace and elevation — across about 50 activities.
- Localization is a product, not a translation. Suu runs in 7 languages, including right-to-left Arabic.
- Privacy has to be designed in. In Suu, voice is converted to text on the device and meal photos are not stored.
5. The numbers after launch are brutal
Launching is the easy part. RevenueCat's State of Subscription Apps 2025 found that across all categories nearly 20% of apps reach $1,000 in revenue and only 5% reach $10,000 — and after their first year, the top 5% of newly launched apps earn over 400 times more than the bottom 25%.5
Health & Fitness does convert free trials well — a median of 39.9%5 — but that only matters once you have trial users. In this category you bid for the same installs as MyFitnessPal, Strava and Noom, which raised a $540 million Series F in 2021 alone.4
What building Suu taught me
I didn't make Suu worth using by building a better water counter — excellent ones already exist. What made it worth building was connecting the three things people usually track in three separate apps: a run recorded on the map raises that day's water goal, a salty meal adds digestion water, and a coffee counts for its real hydration value instead of a full glass of water. That connection is hard to build and hard to copy, because it only works once all three pillars are already good.
Suu still isn't the best at everything. MyFitnessPal's food database is far larger, Strava's segments and social features are unmatched, and Cronometer tracks micronutrients far more deeply. That honesty is the point: if an app that already combines all three still has gaps against the giants, a new generic tracker starts much further behind.
My honest advice
Don't build a general water reminder, calorie counter or workout logger. Each one competes with a funded leader, a free platform app and all-in-one apps like Suu at the same time.
Think twice about “the same thing, but with AI.” The calorie category leader already owns the most successful AI photo app.
Only build if you can name a specific group of people that MyFitnessPal, Strava, Samsung Health and Suu all serve badly — and you can already reach them without paying for every install.
And if you're a user who simply wants water, calories and workouts in one place: you don't need to build anything. That app already exists.
See what an all-in-one tracker looks like
Water, calories and GPS workouts in one app · free on iOS and Android
Frequently asked questions
Is the calorie counting app market saturated in 2026?
At the general-purpose level, yes. MyFitnessPal serves more than 200 million users and acquired Cal AI (15M+ downloads) in a deal that closed in December 2025. Yazio, Lifesum, Cronometer and Lose It! cover most remaining needs, and Samsung Health includes free food logging. A new calorie app needs a clearly underserved audience to stand out.
Is a water reminder app still a good app idea?
Rarely as a standalone product. WaterMinder, Waterllama, Plant Nanny and Hydro Coach are mature, Samsung Health includes water tracking with a daily goal, and all-in-one apps like Suu track 91 beverages with a goal that changes with exercise and meals. Apple's Guideline 4.3(b) also warns against apps that are indistinguishable from what is already widely available.
Which apps already combine water, calorie and exercise tracking?
Suu combines all three in one app where they update each other: photo, voice or text meal logging, water tracking across 91 beverages, and live GPS workouts across about 50 activities, with Apple Health and Health Connect sync. MyFitnessPal and Samsung Health also log food, water and exercise in one place, with different strengths.
How hard is it to build a calorie tracking app with AI photo recognition?
Calling a vision model is the easy part. The hard parts are nutrition accuracy, per-request AI costs, health-data law (GDPR Article 9, KVKK), Apple's HealthKit rules, two-way sync with Apple Health and Health Connect, and localization — and then winning users from MyFitnessPal, which already owns Cal AI.
Can an indie developer still compete in Health & Fitness?
Yes, but not with a generic tracker. Suu is built by an indie developer and competes by connecting water, calories and workouts rather than by out-featuring MyFitnessPal or Strava at their own game. Revenue is highly concentrated: RevenueCat found that after their first year the top 5% of new apps earn over 400 times more than the bottom 25%.
What should I build instead of another tracking app?
Start from an audience, not a feature: a group with a specific problem that general trackers and platform apps handle badly, and that you can already reach. If the idea is MyFitnessPal, Strava or WaterMinder but simpler or with AI, the market already has that app.
References
- Francisco Partners — Announces acquisition of MyFitnessPal from Under Armour (Oct 2020)
- TechCrunch — MyFitnessPal has acquired Cal AI, the viral calorie app built by teens (Mar 2026)
- Crunchbase News — Strava valuation powers up to $2.2B as fitness startup funding falters (May 2025)
- MobiHealthNews — Weight loss app Noom scores $540M in Series F funding (2021)
- RevenueCat — State of Subscription Apps 2025
- Apple — App Store Review Guidelines (4.3 Spam; 5.1.3 Health and Health Research)
- Samsung — Use and manage trackers in Samsung Health
- MyFitnessPal — Introducing the enhanced Meal Scan feature
- EUR-Lex — Regulation (EU) 2016/679 (GDPR), Article 9
Related articles
Water + calories + exercise in one app
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Best calorie counting app 2026
Suu vs MyFitnessPal, Yazio, Lifesum and Cronometer.
Best workout tracker app 2026
Strava, Nike Run Club, Samsung Health and Suu.
Suu vs Cal AI
Photo calorie counting — and what comes after it.
Suu is not intended for medical diagnosis or treatment. Consult a healthcare professional for health-related decisions.