I _quickly_ checked the study [1] and didn't see anything obvious.
Given that our voices reveal so much about the state of a human (think of mood, emotions), I think it's at least possible that voices could reveal something about metabolism. Just we cannot hear it because hearing diabetes is not as useful as hearing something about the mood of another person.
[1] https://www.mcpdigitalhealth.org/article/S2949-7612(23)00073...
It's just because I don't think this is evidence enough to change my priors. i.e. My gut tells me this is wrong and I don't buy it.
The sample is 267 people, tiny enough that I'd expect an analysis to be done with a linear model with few features. They used 14 features, but had a pipeline to select "model (out of 3), feature set, and threshold for prediction".
There's _so_ many degrees of freedom there that _by default_ I assume there's leakage.
I'd love to see this paper replicated! It would be amazing if this were true. But if I had to bet on this, I wouldn't give more than 20% chance of being true.