Intermittent Fasting vs. Caloric Restriction

Since at least the early 1940s, Caloric Restriction (CR) and Intermittent Fasting (IF) have both been known to extend the life of laboratory animals. In CR, lab animals are provided a reduced calorie diet; in IF, animals are subjected to significant fasting periods between meals. Oddly, however, based on virtually all of the people that I have talked to, CR remains the better known of the two dieting strategies. Why?

I would argue that IF is actually superior to CR if the goal is to extend life and prevent disease. In fact, I would argue that CR extends life only insofar as it approximates the fasting state found in its purest form in IF. Recent studies on worms show the much better results of IF vs. CR in extending life: up to 56.6% life extension for worms on IF vs. 13.2% life extension for worms on CR!

Moreover, one of the great advantages of IF over CR is that IF is a much easier lifestyle. Rats on CR live a long but uncomfortable life, rats on IF live a long and more pleasant life. As I will show in later posts, the Fast to Last diet is, after the initial adjustment period, a very natural and agreeable way to live and eat.

To answer my initial question: I believe CR is more widely known because weight loss generally occurs more quickly. Less calories in, and your weight will decline. I would like to emphasize right here, however, the primary goal of the Fast to Last diet is not rapid weight loss -- but a long, healthy, disease-free life.

Sleeping and Fasting

Because the Earth revolves around its axis, for half of each day the world is filled with darkness. Many animals, including humans, have used this "dark" time to sleep. Since many animals rely on sight, there isn't much productive activity that can take place at night. Although it may appear that a sleeping animal is just wiling the time away doing nothing, nature is actually using this down time to do all kinds of regenerative things: dreaming, healing, repairing, resting...... Sleep is so important to humans that a few days without it can be devastating to one's psyche and health. Even though modern technology has made it possible for humans to be productive 24 hours a day, our biological rhythms are so deeply ingrained that sleep is firmly entrenched as a basic human need.

Let us look at another natural rhythm. Evolutionary biology has shown us that organisms are built to survive in a highly competitive world. Resources are not unlimited and most animals are built to survive in a scrappy, competitive struggle for these resources. In the history of life on Earth, only rarely would an organism find itself in the "land of plenty" for any extended period of time. One byproduct of this competitive struggle for resources is periodic bouts with hunger. One of my theories is that intermittent hunger is so natural a state for most life forms that nature has come to actually rely on it to perform many of the regenerative functions that sleep performs on a nightly basis.

Modern technology has made it possible for most humans to completely eliminate bouts with hunger. Many people can go through their entire lives without worrying about their next meal. I would argue that this is actually unhealthy: humans have a biological requirement to be in a fasted state periodically to maintain overall health . For the past several generations, modern humans have found themselves in a technological "land of plenty." Unfortunately we are not biologically suited for this. For the past half-century modern humans have been suffering the equivalent of sleep deprivation with respect to our digestive system. We are suffering from the diseases of affluence.

Did I Invent the "Fast to Last" Diet?

After I came up with the Fast to Last diet, I immediately had three questions: Will this diet work? Is this diet safe? and Has this diet been published before?

Will this diet work? Details on the answer to this question will be explored in future posts.

Is this diet safe? When I first mentioned the diet to my friends, their first reaction was that they had never heard of it, their second reaction was that it sounded very unsafe. The general thinking these days is that one should eat several small meals a day. One of my friends almost freaked out saying that I would do serious harm to my body by following this eating regimen. I decided to ask my neurologist neighbor with a strong interest in diet and nutrition. He had also never heard of it, but said that I would probably do no harm to myself by following the diet.

Did I invent this diet? After talking to several people, including many who follow the dieting world fanatically, and getting a general dumbfounded response, I began to think that I had actually invented a new diet. After a few minutes searching the Internet, however, I found that a very similar diet had been published in 2005. (http://www.fast-5.com/) That diet, the FAST-5 diet, was essentially identical to the one that I had come up with. The only difference was that the eating window was 5 hours rather than 4 hours. Further research showed that this and similar diets fell under the more universal dieting strategy known as Intermittent Fasting (IF) (http://en.wikipedia.org/wiki/Intermittent_fasting) Studies on IF with animals had taken place as early as 1943. So, I quickly realized that I had NOT invented a new diet. I did, however, conclude that this diet was certainly not well known, and for more than a half-century had been generally ignored. I also noticed in the Wikipedia article that a flurry of a dozen or so academic papers have been published in the past 4 years. Could there actually be something to this Intermittent Fasting idea, and might people only now be waking up to it?

Dieting Goals

In the prior post, I discussed how I came up with the Fast to Last diet. In this post, I will discuss some of my dieting goals.

For the past 20 years or so, I felt that my weight has gradually increased to the point where I now weigh approximately 210 pounds. I am 5'9" and feel that this is probably too much weight to be carrying around. I feel a realistic goal is to lose 30 pounds and get to 180. I would like to do this in a very gradual fashion. So I would say a primary reason for my interest in diet is losing weight.

A secondary, although perhaps more important goal, is feeling better. Over the past several years I often eat or drink too much and generally just feel unhealthy. As I mentioned in the previous post, I miss the lean and mean days when I was a wrestler.

A third goal is living a long and healthy life. This is a long term goal that most people wish for, but in terms of diet, is often sacrificed in order to meet the primary goal of losing weight. I will try to show in future posts that this is one of the primary benefits of intermittent fasting (IF).

A fourth goal is avoiding disease. I think, like everyone, I dread the idea of going to the doctor and being diagnosed with hypertension, diabetes, or cancer.

In a future post, I will come back to these four goals and show why IF generally addresses the longer term, rather than shorter term, goals. It is for this reason, it has remained somewhat of a fringe dieting strategy, but, in the long run, has much greater benefits.

How I Became Interested in IF

I became interested in intermittent fasting (IF) after discussions earlier this year with a neighbor in my building - a neurologist with an interest in health and diet. He had developed a diet based on eating non-processed foods to emulate the natural diet of primitive man.

As a bit of a junk food junkie, I thought that this would be a very difficult diet for me to follow. I then began thinking about the natural state of man and, in particular, my own natural cycle of eating and fasting. I came to the realization that, despite what I had been taught, I rarely felt hungry in the morning and usually became hungry only later in the day. I thought a NATURAL diet for me would be one with a fairly long fast period before I began eating each day.

I had also been a wrestler in high school and missed the feeling of an empty stomach that I often had as we struggled to "make weight". I remembered that somehow this empty stomach feeling actually made me feel HEALTHIER and stronger.

I then came up with a diet that I thought would follow my natural eating rhythms and recapture the healthy feelings I had in my days as a wrestler. I dubbed the diet "Fast to Last" diet -- it consisted of fasting for twenty hours of the day and then eating for four hours. The four hour eating window was fairly flexible but I thought 4-8 p.m would work for me.

So, in contrast to a diet which concentrated on the natural content of foods that man is adapted to, my diet concentrated on the natural rhythm of man's eating and fasting. In other words, its not so important what you eat, but rather when you eat.

Intermittent Fasting

August 7, 2009: 210 Pounds

This is my first blog post.

In my first series of posts I will be discussing intermittent fasting (IF). Although I have been dabbling in this diet for the last year of so, I will begin in earnest tomorrow Sept. 1., 2009, I will provide periodic updates on my progress and also some of the rationale behind the diet.

I am 5'9", currently weigh 210 lbs., and am 48 years old.

There are a variety of techniques for IF. The one I will employ consists of fasting for 20 hours of the day and then eating during a four hour window. Typically I will try to fast until 4 p.m each day and then eat from 4 p.m to 8 p.m.