# Source notes

This submission uses only the facts locked in the bounty brief:

- Researchers at the National Institutes of Health compared four widely used phone apps that estimate meals from photographs with meals that had been prepared and measured precisely.
- The apps underestimated the meals by roughly 250–345 calories on average, about one third of the actual amount.
- Fat was the largest miss, underestimated by around 30 grams per meal, while carbohydrate estimates were more consistent.
- High-fat dishes caused the greatest difficulty.
- Fat absorbed during cooking, soaked into food, or pooled underneath it is largely invisible in a photograph; a camera can observe a meal's visible shape and colour but not what has gone inside it.
- The findings were presented as a conference abstract at NUTRITION 2026 and have not undergone full peer review.

The artwork makes no claim about a particular app, brand, sample size, diet, body, or settled clinical conclusion. It introduces no figures or links beyond the locked brief.