I just finished reading the new book, " The Alternate Day Diet", by James Johnson. I will give a full review of it later on, but it has helped me clear up my ideas on things, especially my recent idea of Super-Fasting.
Johnson shows in his book the tremendous benefit of undereating one day and then making up for it by eating more the next day. He describes these as "down-days" and "up-days". I have been wondering how this fits with the concept of intermittent fasting, of which I'm a proponent.
The research shows that while intermittent fasting is good, alternate day calorie restriction (ADCR) is even better. For example, this study shows that daily intermittent fasting during Ramadan confers some benefits. But this study of ADCR shows massive benefits in terms of reducing inflammation and treating asthma.
In the book, Johnson points out that a 36-hour period of low energy seems to be needed to trigger these benefits. He admits that simply not eating for these 36 hours would probably produce the most health benefits, but that few people will do it. Instead, he suggests restricting calories to 20% - 35% of normal intake on these down days, with unlimited eating on the up days. The studies show that this restricted amount of food still produces the lion's share of the benefits, so that complete alternate-day fasting isn't necessary.
My first thought was, how would this 36-hour period of low energy have naturally come about during hunter-gatherer times? One clue is that he mentions how many people turn to vegetables on their down days. That got me thinking about the following pieces to the puzzle. First, we know that hunter-gatherers consumed about 35% of their calories from carbohydrates (plant food). The rest was meat (protein and fat). So let's say a group of hunter-gatherers was not successful in catching game one day. What would they have been left with? Plant food. And the high fiber content of Paleolithic plant food probably naturally limited consumption, and led to a day of reduced calorie consumption. The next day, if they successfully acquired meat, you can be sure that they would overeat to make up the deficit.
Therefore, I think you can extrapolate from the book a very simple and applicable model that can produce health benefits. On some days, eat only fruit, vegetables, and limited nuts, and this will naturally lead to a reduced-calorie day. On the other days, eat fruits, vegetables, limited nuts, but then add in generous servings of meat to make up for the previous day's calorie deficit. If the research in the book holds up, this type of eating pattern will lead to superior health, including reduced inflammation and protection from many diseases.