Intermittent Fasting

Breakfast may be the most important meal of the day, but who says we ought to have it? I like having mine around 5:30 PM.

Welcome to intermittent fasting (IF).

IF is one of those things that is "so crazy it just might work," and I've been using it for about four months with great success. It's a very simple concept: you eat all the same calories that you would in a normal day, but you compress your meals into a shorter time frame.


Why?

1. All of the benefits of caloric restriction are associated with IF, excluding the inability to maintain an athletic body. These benefits include:
- increased lifespan
- improved insulin sensitivity (muscle will be prone to absorb excess nutrients that would otherwise go to fat)
- metabolic state of ketosis (the body burns fat for it's main fuel source; not to be confused with ketoacidosis, a life-threatening medical condition that can occur in diabetics)
- improved cognitive function
- lower likelyhood of cancer
- improvement in body composition
- improved workout recovery and improved ability to gain muscle (blood flow to the intestines is lessened while not digesting food, and more is directed toward muscle repair)
- improved conditions of epilepsy, Parkinson's, Alzheimer's
These results have been proven by numerous studies on mice and primates, several on human beings, and plenty of anecdotal results from people such as myself.

2. It fits in with the model of Paleolithic man. Homo erectus, the earliest ancestor of modern humans came into existence about 1.8 million years ago. Homo sapiens themselves are about 100,000 years old. Humans would have evolved in a lifestyle where they hunted, gorged, then rested until they were hungry again, at which point they would repeat the cycle. Wild animals today do this. Modern humans (and their pets) are the only animals which eat constantly throughout the day, and this is because of our abundance of food (most of which is nutritionally void and calorie-dense, but that is another topic...) and our ability to preserve it.

3. You have complete control over what you eat. If you are able to go 18+ hours without eating willingly, refusing a Krispy Kreme is nothing! This goes for both the fasting period, and even during the eating-window. The fasting gets easier and easier to do, but it is still a choice that you make. You could be shoving your face with chocolate cake 24/7, but you choose to do otherwise, and this choice becomes a good habit.

4. It's really convenient; the system is extremely flexible. You can change you feeding hours, or the length, or whether or not you even fast that day depending on what you want to do. I eat all my meals in the evening, so when I wake up in the morning, I don't have to stumble around to eat breakfast and prepare a lunch for the day. It's awesome. I wake up at 7:15 AM, and at 7:30 I'm out the door on my way to school, feeling completely awake and ready.


How?

1. There are three common methods of IF: randomized, every other day, and daily. RIF is fasting on just a few days a week, and may be as simple as eating dinner at 4 PM and skipping out on evening snacks. In EODIF the fasting and feeding periods are each 24 hours long, eg. you fast from 5 PM to 5 PM, and then you eat double your daily normal before the next 5 PM, when the fast resumes. DIF is a compression of all meals into a short period each day. I chose to do DIF because it is something that I can do consistently and I can't imagine eating a double load in 24 hours with EODIF.

2. It's important to get into this slowly. For DIF, begin with a 12 hour eating window... Pretty much eat breakfast through dinner, but don't have any late-night snacks. Every 5-7 days, knock 30 minutes off either end of the spectrum until your feeding window is 4-6 hours each day, at a time that you enjoy. If there's something you can't get around, like a business lunch or a family dinner, then either move/expand your fasting hours for the day, or take the day off.

3. The better the food choices you make, the better your results will be. This is not to say you can't eat like crap, as some people suggest, but you won't do as well. The Paleo-Diet is the best choice you could make: "if the food could not be found and consumed raw in an unpolluted, natural environment, then don't eat it." This immediately rules out all grains, dairy, and legumes, which are all very new foods in man's evolution, yet some of the foods we consume the most of. If you are worried about getting enough nutrients on such a diet, see this study.

4. Macronutrient proportions are not as critical as they are in The Zone Diet, but they do play some role. After going IF/Paleo for a while, your body will start to crave the foods it needs. Judge your intake by changes in your athletic performance. If there is anything you want to be careful to limit, it should be carbohydrates; 40g-100g a day is good for getting in a ketogenic state while having enough carbohydrates for some daily, intense physical activity. You'll only need to worry about this if you overeat fruit and neglect vegetables. The vast majority of your calories will come from healthy fats like nuts, olive oil, fish, grass-fed meat, eggs, and avocados.

Questions/Concerns:

Won't I loose muscle from not eating protein every 3 hours?
No. When using IF, your body gets very good at efficiently using protein. Keep your calories up, keep working out, and you'll be fine.

Can I drink water while fasting?
Yes, and you should be drinking 3-5 liters a day already. You may also drink black coffee, or tea, since neither of those have any calories. Sugar and cream are out.

What do I do if someone offers me food (especially junk food)?
Say "No thank you." If they insist, say "No thanks; I'm not hungry." It's the truth.

Won't my metabolism slow down?
You'll find that you need to eat less food to maintain your weight, but that your energy levels are also going up, because you are getting a better use out of better food.

I am a diabetic; could this help?
I've seen testimonials of people cutting their insulin in half just by switching to the Paleo-Diet, so definitely start there. For IF, I've seen positive lab experiments on diabetic rats and anecdotal success with humans. If you choose to try it, I cannot urge you strongly enough to take it slowly and to monitor your blood sugar closely. (Don't forget to comment back here if it works!)

What about working out?
After adjusting to IF, you'll have more energy for your workouts and a better recovery between them. However, if you do a particularly intense or heavy workout, you may feel fatigued until you get a chance to eat again. I normally work out at the end of my fast, then eat 45-75 minutes after finishing. Play around with it and see how you feel.

How many meals do you need to eat?
I eat from 3 large meals to 5 smaller meals in my feeding window, but the time between them is short enough (~60 minutes) that I suppose you could call it "one" meal.

Don't you feel really full eating like that?
I had no problems while slowly lengthening my fast. If you go for a 20 hour fast right out of the gate, yeah, you might have some issues. So don't.

How do I cook Paleo foods?
See these articles, and if you like them, there's more in the monthly Performance Menu e-magazine article "Cooking with Scotty;" George Mounce, on the CrossFit boards, has a very nice recipes thread; and Robb Wolf's blog has some more recipes, and a DVD coming out soon.

Where can I go for additional information?
Robb Wolf's Blog
Performance Menu Message Boards
CrossFit Message Boards
Protein Power


With 8-9 hours of sleep each night, IF/Paleo eating, and a good training program, these past four months have been the happiest and most enjoyable of my entire life. I hope you can achieve the same.