Review of ...
The Alternate-Day Diet, by James B, Johnson
Putnam Adult, 2008.
The Alternate Day Diet explains some of the relevant science behind calorie restriction as both a health-conducive regimen and a weight control strategy and offers valuable experience-based practical advice. There is a lot of evidence in favor of strategic intermittent calorie restriction for making us healthier but there are also some pervasive arguments that have been made against it. Johnson directly addresses each of the arguments and concludes, partly from research he cites and partly from his own experience with patients, that alternate day calorie restriction is practical, effective, and healthy for a wide range of people.
Intermittent calorie restriction is a welcome and refreshing strategy in the diet world because it has the distinct potential to help explain some of the benefits of the other approaches and resolve some of their competing claims. Johnson's conclusion, and the evidence he cites in favor of intermittent fasting, is consistent with the evidence of health benefits for other approaches such as "low carb," and "paleo," because of the significant overlap between those strategies and general calorie restriction. For example, calorie restriction, low carb, and paleo approaches all involve minimizing high glycemic intake, although they use different rationales to explain the outcomes.
This book is also welcome because it offers a perspective that seems to me to help dissapate some of the supposed tension over whether "calories in vs. calories out" is more important than "metabolism" in weight control. If strategic fasting is healthy and effective in weight control, then overall calories may very well matter, but so does metabolism. Fasting appears to hit both targets at once, through the effect of calorie restriction on genetic mechanisms of metabolic regulation.
The key idea behind intermittent fasting as presented by Johnson is that even severe calorie restriction for only 24 hours at a time is not only tolerable, but sustainable over time, and in fact does not cause us to hoard body fat by shutting down our metabolism. The alternate day fast, according to Johnson, seems appropriate to nearly anyone without such serious contraindications as insulin dependent diabetes. He also finds no evidence that intermittent fasting further encourages restriction in people predisposed to anorexia (although I would add that it may help them rationalize their pathological restriction).
I'll add that I've been using Johnson's alternate day fasting approach for several weeks (and prior to that had used the recommendations in Brad Pilon's "Eat Stop Eat" intermittent fasting program for several months) and have so far found everything he says to be true from my own experience. It is not at all difficult to get used to eating very little on alternate days, especially if you combine this approach with some knowledge of satiety (see Barbara Rolls books such as Volumetrics), it does not seem to encourage me to eat more on the non-fasting days, it does seem to have a steady body fat reduction effect, and it seems to have positive effects on how I feel both physically and emotionally. So far I have not found alternate day fasting to have any negative impact on my activities, and I think it has had a small positive effect on my energy levels.
I can't say that the approach would work for an elite athlete or bodybuilder who lives on a much larger scale of intake and output, but it seems like this approach has a lot to recommend it for most of us. Being successful with alternate day fasting will take some new habits, and probably a shift in attitude toward meals, but I think it is a viable weapon against obesity for those who can do it (and it seems to me that those who can't succeed with this approach will probably will have problems eventually with any approach) and a valuable tool for better health.
I bought this book on Kindle, and it is well served by that format. I highly recommend it for its reassuring scientific evidence and its practical advice. I would enhance this approach by learning as much as you can about satiety (such as from Barbara Rolls books on Volumetrics) so that you have even more strategies for feeling comfortable with calorie restriction while still getting healthy nutrition from the reduced intake. The alternate day fasting approach does not tell you what to do on your non-fasting days (other than to avoid either fasting or gorging), so it's still up to you to learn how to eat healthy on those days. The author doesn't abandon you on the "up" days, he does offer some standard suggestions for healthy eating, but these are a small part of the book.