One of the big benefits of going keto is satiation. Fat is harder to digest and provides the body more energy per gram, so it keeps you full for longer periods of time. It also does not stimulate the much-dreaded insulin response that increases both fat creation and storage as well as false hunger cues. This is good for the body, not only for reasons of self control, but also for general health.
Intermittent fasting- wherein one limits their daily meals to small windows of time (usually in the four-to-six hour range) while not required, is something we tend to recommend in conjunction with the ketogenic lifestyle. Fasting is well known for helping a body that is damaged by insulin resistance recover sensitivity and normal function. Most people tend to fall into sixteen-to-eighteen hour fasting periods fairly naturally after a few months of eating keto simply because they're finally truly nourished, and consequently not very hungry.
Yet another reason why keto and fasting are great for human health is a bodily function called autophagy. Simply put, autophagy is the process by which the body naturally takes apart and purges your cells of dysfunctional parts. Over time your cells, or parts of them, can naturally degrade. The entirety of every cell in your body has a pre-programmed lifespan and "death" (called apoptosis). This is perfectly normal, and is a natural 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. Once those old cell parts are broken down, they're sent to other parts of the body to be recycled (or "up-cycled") into creating new energy or to rebuild other cells.
Damaged cells, usually, don't have fully functional mitochondria (the powerhouse of the cell), so they don't manage energy as well as they may have earlier in their lifespan. Getting rid of damaged cells, and having new ones built to replace them means, over time, you'll have better energy partitioning at a cellular level.
What Does This Have to Do with Keto?
Ketogenic eating keeps us full and we can go longer and longer periods without eating, the result of which is circulating insulin levels that are low and stable. In addition to all its other metabolic functions, insulin also operates as an "off switch" for autophagy. When an insulin response is triggered, autophagy stops. This is because autophagy is tied to the hormone glucagon, which is what keeps your blood glucose steady when you are fasting or when you're 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 the release of one triggers the drop of the other in your body.
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.
So What Does This Mean?
It does not mean you need to starve yourself to detox or purge bad cells. It does mean that you should not eat mindlessly or out of boredom, so as to avoid an unnecessary insulin response that stops the body's natural healing.
Autophagy seems to peak between the sixteen and twenty-four hour marks during fasting. If you can keep your meals within a six-to-eight hour window every day, you're going to help your body along while it's performing this necessary maintenance. If you're a fasting pro, some of the most common recommendations in regards to helping the body to naturally and properly regulate autophagy are the twenty-four hour fast, performed once or twice a week (frequently called "alternate day" fasting). Keep in mind, you don't have to do any of this to be keto, but it is easier to do if you are keto. Work with your body and it will work for you.