Roughly speaking, autophagy is the cannibalization by a cell of defective or questionable molecules to make new, higher-quality molecules. Autophagy is now thought to be quite powerful in reducing disease risk, because it provides quality-control for key types of molecules in the body. This is like saying that your car is likely to break down less if it gets regular servicing—including, crucially, the replacement of parts that are wearing out with new parts.

Low nutrient levels encourage autophagy. One way to induce autophagy is to do a total fast from food for an extended time, only consuming water and plain tea or coffee. But suppose you have trouble doing a total fast from food—what then is likely to be the most powerful way to induce autophagy? I think there is a plausible answer. If you fast totally, your body will be breaking down body fat, and there will therefore still be fat in the bloodstream. So I suspect that eating, as nearly as possible, only fat is likely to keep the signals for autophagy most powerful. And of course, eating as little of that as you can be OK with helps close whatever gap their is between the body’s signals when consuming only one’s own body fat and the body’s signals when consuming some amount of fat from outside.

lmportantly, this is not describing a typical “ketogenic” diet because ketogenic diets often include a lot of meat, which has a lot of protein. I suspect that consuming protein has a substantial effect on signals for the cannibalization of low-quality or possibly low-quality proteins that were already in the body. Among common dairy products, butter has the least protein (and clarified butter the least of all). So some amount of butter is probably OK when you are trying to induce autophagy. Macadamia nuts are also probably OK.

All of this needs additional research. Such research matters because not everyone can tolerate an extended total fast from food. I’d be happy to be corrected on my conjecture above if there is evidence against. More generally, I am very interested in learning more about autophagy and related subjects and would welcome links to articles you think I should see on this.

For annotated links to other posts on diet and health, see:

• Miles Kimball on Diet and Health: A Reader's Guide