The brain, and other parts of the body, recycle. The process is called autophagy. It’s what happens when you fast and sometimes happens without having to fast. The person who discovered it’s positive impact on people won the Nobel Prize in Medicine recently as a result of their work. It’s important that bodies can access it.

There is much scientific literature on autophagy only a Google away. It’s well worth the time spent trying to understand it. When you fast, your body eventually goes into autophagy, which essentially means it starts cleaning up and destroying old and broken cells, and using their parts for energy and repair. It’s necessary for our body to get into this state. It’s natural for a feast and famine animal to spend periods without food.

One reason modern people tend to be afflicted by neurodegenerative disorders seems to derive partly from issues involving the lack of autophagy in our lives. Without cellular recycling, bad cells can build up and form plaques. We need to go into autophagy in order to keep our cells functional, hence the benefit of fasting. Fasting can hardly solve Alzheimer’s, but it appears it can be protective against it at least in part.

To maximize the benefit of fasting and take full advantage of the natural cell recycling process called autophagy, you have to fast for longer than 16 hours (men) and 13-14 hours (women) at a time. At that point autophagy kicks in. The benefit diminishes entirely by 48 hours, or about 30 hours a month, of fasting. So if you want to get full benefit, you can fast for 48 hours once a month or 24 hours once a week. Less if female.

When we fast, our body looks to existing sources for food. Contrary to popular opinion among bodybuilders, this is less often prime muscle cells, and more often waste cells that need to be recycled for parts because they no longer function and will simply build up in undesirable places (your brain) over time. The proteins and energy in the cells can be reused more usefully by other parts of the body. Even the nutrients themselves can be appropriated for use elsewhere. It’s interesting that this highly antifragile process is built right into us.

Relative to other diet advice, it doesn’t require (or sell) books to say “eat less frequently”. It does however set off autophagy when you do, something that is critical for all people to engage in or else end up compounding the problem of neurodegenerative diseases. I do one 24 hour fast once a week, and find many benefits. Try it out.