Fasting-mimicking diets can induce a ketogenic mode by day two, leading to the system switching to burning visceral fat and ketone bodies for energy.

“Because overnight, most of that 14 hours, you got some glycogen to burn, right? So, you're not really needing to do much of a switch to anything else. And that's fine, and I think it's good, you know, shouldn't go over that because it's just a continuous thing, you know. You don't wanna push the system too much into these extreme modes all the time. It's different from the fasting-mimicking diet because, as I said, you know, the fasting-mimicking diet I really, by day two of the diet, and only by day two or so of the diet, the system starts switching to a ketogenic mode. You start burning visceral fat as your major source of energy. Your brain starts moving from burning sugar, to burning ketone bodies, beta-hydroxybutyrate.”