It occurred to me when I was in Med School that there is no reason biochemically one could not fast totally for weeks as long as you had residual fat stores. Over my 35 year career I have advised several >300 lb people fast and offered to help them. One lady asked me for help losing 75 pounds because she “was afraid of losing her husband”. She lost 75 pounds over a 3 month fast and she looked hot at the end. Other doctors told me I was crazy for recommending total fast but no one ever complained or was hurt by it. In fact, I find that when you become totally ketotic in 72 hours your mind clears immensely and you realize just how much toxins are in food.
I have noticed that my mind is much clearer when I am hungry. Absolutely no brain fog.
In fact, when I was younger, my work crowd use to refer to the carbohydrate hangover that came from eating pasta and other delicious high carb foods. Folks were drowsy at work the day after eating a big Italian meal the night before.
None of that when fasting.
You can live 4 minutes without air, four days without water, and forty days without food. Stay hydrated, drink plenty of water, and after the first 24 hours or so, the “hunger pangs”, which are really a learned habit, are greatly lessened. After 24 hours or so, the body stores of glucose are largely exhausted, and the body turns to the “keto burn”, the extraction of energy from stored body fat. In the process, the muscle tissue, largely protein, is also being burned, so when the fast is broken, after 36 hours, or 48 hours, or 72 hours, concentrate on eggs, cheese, or high-protein vegetable sources such as peas, beans, or various seed kernels, which restore first the depleted protein of the muscle tissue, then continue to burn the fat tissue.
This sounds a lot like the “Atkins diet”, and is related to it. The idea is to keep the body off glucose to the greatest degree that can be done short of total starvation, until the homeostatic levels of the body are reset to the new lower levels of glucose and higher levels of protein, and yes, fats. If carbohydrates are consumed, try to concentrate on “low-glycemic” foods, in which the glucose is released only slowly into the blood, preventing those “sugar spikes” that send the appetite spiraling, sometimes out of control.
We know how. The great challenge is to apply that knowledge.