[DoreenMichele]

The reason why intermittent fasting works is that it is associated with increased oxidation of fatty acids (lipolysis) and ketone body formation (ketogenesis), activated cell-signaling pathways (insulin sensitivity, reduced inflammation, autophagy), and preservation of lean body mass, known as “metabolic switching”.

The interesting fact however is that typically, these mechanisms are not fully activated until at least 24 hours of fasting.

Well, this sounds to me like they know it has an effect but they don't actually know the full story on why it works.

[WithinReason]

That's when you consume your glycogen stores

[DoreenMichele]

Yeah, but my point is that IF is generally under 24 hours, yet has an effect. So they seem to not have a good explanation for why IF helps given that their hypothesis fits what we know happens after the 24 hour mark and you aren't doing that.

"We know it works because after 24 hours, X happens" does not explain why it works when you aren't hitting that mark. Sorry.