I just fed 4o and o4 mini a photo of my torso and gave it my height and asked it to estimate my body weight and body fat %. It was 20-40 lbs too low, so way off.
So that is obviously a significant relationship between ChatGPT estimate and the Henselman Guide BFP numbers. But just being a significant relationship doesn't necessarily mean it's useful. I'd bet that BMI (which the author repeatedly mentions is outdated and not very useful), is almost certainly also significantly correlated with BFP values.
Eyeballing that plot, it looks like ChatGPT estimates are +/- 10%. I'm wondering what the cutoff for usefulness is. I wouldn't' be surprised if BMI is that level of correlated or better.
That doesn't do anything to address my concerns. I was talking about the total spread, not the mean error, but in either case, a comparison to how well BMI correlated would be needed to address the issues I raised.
Just by looking at the graph I know that this will be rubbish - because of the line
When you draw a line this means that your model expects a linear relationship between the variables. Otherwise this is either a feel good line, or incompetence.
Try using images that it wasn't trained on.