An excellent point. Heres part of an article tied to ketosis or a keto diet.
"Over time your cells, or parts of them, can naturally degrade. The entirety of every cell in your body actually has a pre-programmed death (called apoptosis). This is perfectly normal and is a part of how our body constantly expels old material and replenishes itself with new cells. When only parts of the cell are damaged and in need of replacement autophagy is the process by which that happens. And once those old cell parts are broken down theyāre sent to other parts of the body to be recycled into use for creating new energy or to rebuild other cells.
Damaged cells, usually, donāt have fully functional mitochondria (the powerhouse of the cell), so they donāt manage energy as well. Getting rid of damaged cells, and having new ones built to replace them means, over time, youāll have better energy partitioning at a cellular level.
Great, Mandy, what does this have to do with keto?
Well, Iām glad you asked.
Because Ketogenic eating keeps us full and we can go longer and longer periods without eating, we keep our insulin levels low. Insulin, it turns out, in addition to all its other metabolic functions, also operates as an āoffā switch for autophagy. When insulin response is triggered, autophagy stops. This is because autophagy is tied to glucagon, which is the hormone that keeps your blood glucose steady when you are fasting or when youāre not feeding your body stuff that raises blood sugar. The glucagon levels in your system trigger autophagy. Insulin, which lowers blood glucose levels by shoving excesses into your cells to be stored as fat, is the biological opposite of glucagon and its release triggers drops in glucagon.
The longer you go without eating (in other words, you are in a fasted state), the longer you have gone without an insulin response, the more glucagon gets floating around your system. Glucagon simultaneously tells the body to begin the process of autophagy and to produce the growth hormones needed to regenerate cells and cell parts that are in need of replacement. As soon as you stimulate insulin release, all of that stops cold."