I wonder as well. The caveat at the top could have been a little stricter: I'm being a bit loose with some of the technical details here but I don't think any of the explanations are incorrect nor misleading.

Two caveats I didn't mention are: results will differ per individual (as always), and: some of bits of science here are more hotly contested than others. But that is itself a whole topic on its own: the skewing and manipulation of diet research.