AI nutrition coach
Every calorie app is guessing. This one finds out.
Photograph your food. Step on the scale. Marble works out what you actually burn — and corrects the target it gave you on day one.
The scale
Your scale lies. Every morning.
The correction
Two weeks in, it tells you it was wrong.
- Planned
- −1.1 lb / wk
- Measured
- —
- Weigh-ins
- 1
Day one. The target is arithmetic, and arithmetic can be wrong.
It moves half the gap, never more than 250 calories at once, then waits another fortnight before it touches the number again.
The app
Three screens. Nothing to learn.
What's left, and what you ate. One timescale, no streak to protect.
Where the number starts
We show you the shaky line.
What it asks of you
Nothing, to begin with.
- No account
- No email
- No permissions on first launch
- Weigh-ins never leave your phone
- No streaks
- No cap on meals, ever
Questions
The ones worth answering honestly.
How accurate is a photo, really?
It's an estimate. But reading your meals a little low every time just means the corrected target settles a little lower to match — and your results still land where you wanted them. Consistency matters more than accuracy here.
Do I have to weigh myself every day?
It's the thing that makes the rest work, and it takes ten seconds. Daily is also less stressful than weekly: when every reading is one dot in a line, no single morning is a verdict.
What does it cost?
Logging is free and unlimited — photos, weigh-ins, your trend, and the correction. Meals are never capped, because an incomplete record would make the correction wrong. The conversational coach is the paid part.
Where does my data go?
Your weigh-ins never leave your phone; the trend and every correction are computed on the device. Meal photos are sent to be analysed, and that's the only thing that goes out. Detail on the privacy page.
Is this a good idea if I've struggled with food?
Talk to a doctor or a dietitian first. Marble hides single readings, refuses to celebrate streaks, and tells you when a scary morning is meaningless — but it is still an app that counts, and counting isn't right for everyone.
Stop trusting the number.
Start measuring it.
Free, no account, and it will tell you when it's wrong.