Water
Workout timer
The timer keeps running if you switch tabs or close the page.
Today's workouts
Trending for weight loss
Popular lower-calorie, higher-protein meals from across TikTok, YouTube and Instagram, with estimated macros and a link to the source. Macros are estimates — adjust after logging.
Trending, but skip these
Coach
Ask about your day, plan a meal, or just say what you ate and the coach will offer to log it. It sees your targets and today's diary.
The coach needs Claude
It runs on your own Claude account inside this page. Open Macronaut on claude.ai and allow it when asked.
Calories
Macros
daily average on logged daysWeight
Highlights
Weight goal
This week
My goals
Sync
Enjoying Macronaut?
It's free and has no ads. If it's helping you, a small tip keeps it going.
Your details
Your targets
Calories use the Mifflin–St Jeor formula for resting energy, times your activity level, plus your goal adjustment. Protein is set at 1.8 g per kg of body weight, fat at 25% of calories, and carbs fill the rest.
AI features
Photo logging, the Describe shortcut and the Coach run on an AI model you connect with your own key. The key stays in this browser and talks straight to the provider you pick.
Health apps & camera
Bring your weight and workouts in from Apple Health or Samsung Health, and use your phone camera to log food.
Import weight & workouts from a Health export
Import weight & exercise from exported CSVs
Used for Photo, Barcode and label scanning
Live background sync with a phone health app needs the native mobile version. In this web app you import an export whenever you like — the file you pick is what you share, nothing is read automatically.
Barcode library
Favorites
Appearance & data
A backup is one file with your whole account — diary, workouts, weight, library and settings. Keep it safe, and use it to move your data into a future version or a real app.
Unit converter
Metric ↔ imperial for weight, volume, length and temperature. Type in either box.
Volume uses US measures. Rounded for everyday use.