Fuel tracks water, other fluids, and caffeine as first-class nutrition data so hydration shows up alongside macros instead of being hidden in notes. For the training-day fluid and electrolyte targets that drive those numbers, read The Complete Guide to Hydration.
01The H₂O card on Today
The water card on Today shows your daily water intake against your target with a clear progress indicator. Enable or disable it from Today View Personalization under Show Water Progress.
The hydration timeline keeps drinks visible as you log through the day, so you can see when you drank and where the gaps are.
02What Fuel tracks
Fuel records three hydration signals.
| Signal | What it measures |
|---|---|
| Water | Plain water and water content from other beverages |
| Fluids | Total fluid volume including non-water drinks |
| Caffeine | Stimulant intake from coffee, tea, and energy drinks |
Caffeine readouts appear alongside fluid volume so you can see both hydration and stimulant intake in one view.
03Logging fluids
You can log water and other drinks in three ways.
From food logging — When you log a meal that includes a drink, Fuel extracts fluid and caffeine data automatically. A coffee logged as part of breakfast will add both water content and caffeine to your hydration totals.
From the water card — Tap the water card on Today to add a quick water entry.
From entries — You can log fluids directly from existing food entries when a drink component was missed.
04Smart fluid classification
Fuel uses AI to distinguish drinks from food in mixed descriptions. Names like "water spinach" or "coffee with eggs" are classified correctly so your hydration totals stay accurate.
If a meal name is ambiguous, Fuel separates food and drink components so calorie and hydration totals do not cross-contaminate.
05Water reminders
Smart water reminders send when today is meaningfully behind your water target. They adapt as you log, so they disappear after you drink.
See Smart Notifications for timing, quiet hours, and reminder configuration.
06Apple Health permissions
Water and caffeine data writes to Apple Health when permissions are enabled. If hydration views look empty even after logging, check Apple Health Permissions for the Water and Caffeine categories.
