Google's new AI can read your body fat from two phone photos — and it beats your smartwatch

PhotoScan is still a research prototype, but its accuracy already lands closer to a real DXA scan than the sensor in your smartwatch.

Aliteq
Lena Fischer · AI & Local Compute Editor

The short version

PhotoScan is an experimental Google Research AI model that estimates body fat percentage, fat distribution (android/gynoid ratio) and visceral-vs-subcutaneous fat from two smartphone photos — one…

The short version

It was pre-trained on 35,323 UK Biobank records with MRI and DXA scan data, then fine-tuned on a 677-person cohort and validated on an independent 132-person group.

The short version

Its body-fat-percentage error (mean absolute error of 2.13-2.15 percentage points) beats the bioelectrical impedance sensors used in smartwatches, per Google's own comparison.

The short version

It can also flag insulin resistance risk from the same two photos, with 76% classification accuracy (AUROC 0.760) — close to a clinical DXA scan combined with demographic data (AUROC 0.773).

The short version

It's a research prototype, not a shipping Pixel or Fit feature — Google hasn't announced when or if it becomes a real product.

My take

The accuracy here is genuinely impressive, but an AI trained to read your body composition from photos raises exactly the kind of health-data question Google has stumbled on before. Before this…

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Google's new AI can read your body fat from two phone photos — and it beats your smartwatch

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