The primary goal of intermittent fasting or time-restricted feeding is to extend the duration of unfed states.

“As you mentioned, insulin sensitivity in the metabolic switch is something that Dr. Mark Matson coined and I love it because I feel like, you know, thinking about intermittent fasting in that way makes it a little more clear as to the benefits of it. It depends on the meal you have and how much exercise you do, right? But on average, let's say 11 12 hours to deplete your liver glycogen levels. And once that happens, you do start to burn fat and use fatty acids as fuel and make ketone bodies. So you go into ketogenesis, right?”

“Well, both of these depend on this idea, as the commonality is this prolonged period of fasting. When I say prolonged, that's usually longer than six to eight hours because that's how long it takes for glycogen to deplete or maybe the fatty oxidation to begin so that we begin to use some of the fat. And you also pointed out ketone bodies and beta-hydroxybutyrate, those are also produced maybe after 8 to 10 hours.”