I'm getting a bit tired of seeing the "pseudoscience" label slapped on an argument every single time evolutionary biology is mentioned. I understand why one might want to do this occasionally, but I feel the pendulum has swung too far in the other direction, and now the label is being abused.
This is basically the new "correlation is not causation" meme equivalent. Yes, correlation indeed does not equate causation in a strict sense. But given a large enough number of samples, it becomes the domain of statistical analysis, and then causation can be solidly inferred with a well determined degree of confidence.
So be careful when repeating trendy memes. Trendy does not equate truthful.
Anyway, to provide some kind of answer: Seeing how studies keep coming in, showing that I.F. is beneficial in a number of different ways, seems to suggest that this regimen is, indeed, better overall for your health than 3 meals a day every day. The jury is probably still out, but perhaps getting close to returning for a decision now.
Also, the 10k year "adaptation" is a weak argument. We've adapted in some ways, yes - lactose tolerance, etc. In other ways the intracellular biochemistry has not changed. 10k years is a short time after all; it allows some adaptations but it's too quick for big changes. Our distant ancestors very likely did not live on a steady caloric input, and the time is too short for us to have adapted completely to a different feeding pattern.
Yes, I agree it's hard to know for sure, that's why I used expressions such as "virtually certain" and "strongly doubt". Both suggest a degree of uncertainty. I was not making it into a science, by any means.
TLDR: Nuance, instead of binary logic.