Food Snap test data · September 2026
How consistent is AI photo calorie counting?
We ran 99 meal photos through Spotwell’s Food Snap twice each and compared the results. Here’s what we found, including where it falls short.
Scan the same plate twice
This measures consistency, not accuracy against a weighed meal. A consistent estimate is the first thing you need before accuracy means anything.
| Typical calorie gap between two scans | 4–5% |
|---|---|
| Scans within 10% of each other | 70–78% |
| Scans within 20% of each other | 96–97% |
| Same meal title both times (after naming fix) | 85% (was 17%) |
| Typical time to a result | about 3–4 seconds |
What we learned
Smaller photos didn’t hurt accuracy
Sending photos at 1280 px instead of 2048 px gave the same calorie estimates on average (+0.3% difference) while cutting upload size several times over and speeding results up.
Temperature 0 helped repeatability a little
Making the model more deterministic narrowed the typical gap between repeat scans from about 5% to 4%. The worst 10% of plates still differed by around 14% or more.
Naming, not calories, was the biggest inconsistency
The model often described the same plate differently (“steak and vegetables” vs “steak with mashed potatoes and vegetables”). A fixed title rule raised identical titles on repeat scans from 17% to 85%.
Cuts of meat are a blind spot
A cooked ribeye and sirloin look alike in a photo but differ by roughly 40% in calories. That is why Food Snap asks you to pick the cut instead of guessing.
Method
- Photos
- 99 food photos from recipe sites and public image libraries, across cuisines: plated dinners, bowls, sandwiches, breakfasts, snacks and desserts.
- Procedure
- Each photo was sent twice with the exact prompt and settings the app uses. We compared total calories, the set of foods named, and the meal title.
- Limits
- We did not weigh the meals, so these numbers describe consistency, not error against ground truth. Results can change as the underlying AI model changes; we re-test when it does.
- Using this data
- You’re welcome to cite these figures with a link to this page.
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