Nutrition · Macros
The macro tracker that sets your macros and counts every gram.
Made in the UK by Bolt Business Limited, company number 16864050 · No ads, no trackers
Health AI is a macro tracker for iPhone. It works out your daily calories, protein, carbs and fat from your body, your training and your goal, then counts every gram you log against them. Log a meal from a photo, a nutrition label, a barcode or the UK's own food tables.
- 3 days free
- Then £9.99 a month
- Cancel any time in your Apple account
Your targets
What should my macros be?
UK advice is about half your calories from carbohydrate, at most 35% from fat, and 0.75 g of protein per kilogram you weigh. Health AI's Balanced split sets protein at 1.5 g per kilogram, fat at 30% of your calories and carbs the rest: at 70 kg, 175 cm and 2,000 kcal, 105 g, 67 g and 244 g.
The Department of Health's figures, from the British Nutrition Foundation's guides to nutrient requirements, fat and protein.
The five splits, and the grams each gives at 70 kg and 2,000 kcal
Calories come first, from the Mifflin-St Jeor formula, your training and your goal. Each split then sets protein from your weight, holds one macro at a share of the day and gives the third the rest.
| Macro split | How it divides your day | Protein, carbs, fat |
|---|---|---|
| Balanced (the one the app recommends) | Protein 1.5 g per kg, fat 30%, carbs the rest | 105 g, 244 g, 67 g |
| High Protein | Protein 2.2 g per kg, fat 30%, carbs the rest | 154 g, 195 g, 67 g |
| High Carb | Protein 1.5 g per kg, fat 25%, carbs the rest | 105 g, 269 g, 56 g |
| Low Carb | Protein 2.0 g per kg, carbs 20%, fat the rest | 140 g, 100 g, 116 g |
| Keto | Protein 1.5 g per kg, carbs 5%, fat the rest | 105 g, 25 g, 164 g |
At 70 kg and 175 cm. Protein's own limits are on the protein tracker page.
What changes your targets later, and what leaves them alone
| You do this | Your targets |
|---|---|
| Log a new weight | Worked out again for it, by your split. |
| Log a new weight, with targets set by hand | Left as you set them. |
| Change your calories | Carbs and fat move. Protein stays. |
| Change one macro | Calories stay, and the split becomes your own. |
| Reset to recommended | Back to Balanced, from your body, training and goal. |
Macros more than 25 kcal off your calories? Match macros to calories closes the gap with carbs and fat.
Trends: your average macros, and what you actually burn
Trends averages your logged days over a month, three months, a year or all time: each macro against its target, and as a share of what you ate. Empty days are left out, not counted as zero.
| In the last four weeks | Needed |
|---|---|
| Days with food logged | 14 |
| Weigh-ins | 3 |
| Days from the first weigh-in to the last | 14 |
Then it measures what you burn from what you ate and what your weight did. If your target is 75 kcal or more out, it offers a corrected one, unless the gap looks like food going unlogged or a run of unusual weigh-ins.
- 3 days free
- Then £9.99 a month
- Cancel any time in your Apple account
Cancel at least 24 hours before the three days are up and you pay nothing.
Logging
How do you track macros?
Log each meal and the app does the sums. A photo of your plate, a nutrition label, a barcode or a search gives each food's protein, carbs and fat, which you check before it is saved. The diary then shows each macro against its target, such as 132 of 230 g of carbs.
Where each food's protein, carbs and fat come from
A photo scan estimates the whole plate. A label scan reads the panel, with fibre, sugar and salt. Barcodes are looked up in Open Food Facts and USDA's branded foods, and never use a scan.
Search covers 2,854 foods from CoFID, the UK government's food tables, and 7,793 from the USDA, even with no signal. Quick add takes calories, and macros if you know them.
The coach reads your last 30 days of macros
The coach reads each day's calories, protein, carbs and fat for the last 30 days, with your targets and your split, so it can suggest food that fits.
Its buttons open a food for you to add; it never logs anything itself. More on the AI fitness coach, or everything Health AI does.
What £9.99 a month includes, and what keeps working if you stop
| What you get | 3 free days | £9.99 a month | If you stop paying |
|---|---|---|---|
| Meal and label scans | 30 | 200 a month | No |
| Barcodes, search and logging by hand | Yes | Yes | Yes |
| Messages to the coach | 50 | 300 a month | No |
One plan, and one free trial per Apple ID. Whatever you logged stays yours if you stop paying.
One plan, worked out
One set of macros, as the app works them out.
Follow the sums for one person, from her answers to a weigh-in
Questions
Macro tracking, answered.
Is there a free macro tracker app?
Many are free with adverts, or free with a paid tier. Health AI is three days free, then £9.99 a month, with no adverts. If you stop paying, logging by hand and scanning barcodes keep working.
What is the best macro tracking app?
The one you will keep using. If you only count calories, a simpler app may do. Health AI suits people who want their macros worked out for them and kept in step with their weight.
Can I set my own macros?
Yes: in Nutrition → Settings, tap any target and type your own. Protein can't go below 0.8 g per kilogram, and your own targets stay put when you log a new weight.
Can I track macros on keto?
Yes. The Keto split holds carbs at 5% of your calories, 25 g at 2,000 kcal, with protein at 1.5 g per kilogram and fat the rest. There's no separate net carbs count.
How do I cancel the free trial?
In your iPhone's Settings → your name → Subscriptions. Cancel at least 24 hours before the three days end and you pay nothing.
Coming to the App Store in the UK, for iPhone with iOS 17 or later. Screens show sample data.
Every macro, added up for you.
Food, training and runs in one app, with a coach that reads your last 30 days of all three.
- 3 days free
- Then £9.99 a month
- Cancel any time in your Apple account
Cancel at least 24 hours before the three days are up and you pay nothing.