Our Longevity Diet

There are dozens of different popular intermittent fasts, and hundreds more variations possible. But in general, they divide themselves into two major groups: intermittent fasting with calorie restriction, and intermittent fasting without calorie restriction. Basically, these are like they sound — in the first, you not only limit when you eat, but you try to structure it so that you eat less calories during your eating times than you had prior to taking up the fast. With calorie unrestricted fasts, you still limit when you eat, but you try to structure it so that during your eating times you have just as much food as you normally would if you were not fasting.

We are following a schedule that is calorie unrestricted. Yet we still manage to lose weight. How can that be? Well first, there is not a complete correlation between calories consumed and calories used by your body. That assumes 100% absorption of calories by your digestive system, which is unrealistic. Human waste may not be high enough in calories to cook on, like cow manure, but I’m sure it has some calories in it. Perhaps after fasting it has more — I’m really in no position to test that, but merely suggest it as a possibility.

Another possibility is that we are eating less, but just don’t realize it. We eat the same main meal as before, plus a small meal or snack — breakfast on alternate days and an evening snack on the days we don’t eat breakfast. But during fasts we eat nothing, so there is no temptation to snack between meals, because we are not eating meals then. And when we are in the eating period, we are much more aware of our food consumption. We still may have an occasional handful of nuts or piece of fruit for a snack, but probably not as often as we did before taking up the fast.

Some people say your stomach ’shrinks’ when fasting. I don’t know if this is literally true (the stomach is capable of expansion, so it makes sense it can get smaller too, when not kept as full as previously) but it certainly is an accurate description of how it feels — you just don’t want to eat too much, and have less desire for between-meal snacks.

So, of the two types of fast, intermittent fasting without calorie restriction can still lead to weight loss, though slowly and gradually — it is more likely to be permanent loss then temporary weight-loss diets provide. Intermittent fasting with calorie restriction should lead to more rapid weight loss, though for us that was not the case when we temporarily switched to a Fast-5 style diet. Regardless, it seems logical that a calorie restricted diet would be much more difficult to maintain over long periods, and should not be considered for a lifestyle choice.

If you have a lot of weight you need to lose, and find a calorie restricted intermittent fast works for you, then by all means use that to reduce weight. But for a lifestyle choice — for an eating schedule you can stick with for the rest of your life, and that you can count on to bring both health benefits and to keep off the weight you loss — choose a calorie unrestricted fasting regime. It is easy enough to live with, and the benefits are tremendous.