Intermitant fasting

[Brad Kohler]

Thinking of trying intermitant fasting. New to the idea. Was thinking of eating a zone 5 meals a day on the workout days(3 WOD's), and on rest day doing the intermitant fasting. Or possibly doing the fast every other day (any thoughts?). On the rest/fast days I wouldnt eat till 5:oo pm and eat all my zone/blocks within a 4-5 hour time period. I am a bit of a night owl, and usually go to bed around 1:00 am and awake at 9:00am. Is the fast period too long or too short?
I am around 6-7% bodyfat and currently 148 lbs, would like to reach 160lb over the next year while maintaining the same body fat. Will intermitant fasting help or hinder my goals?

[Josh Brehm]

What is intermitant fasting for?

[Chris Forbis]

Josh-

This is a short answer. Lots of long answers in the archive...

Caloric Restriction (CR) has been shown in mice to increase longevity. The problem is that the mice get obscenely thin. Intermittent Fasting (IF) has been shown to deliver the same benefits without the obscene thinness. The key is to not restrict total amount of calories consumed, but just limit the time frame in which one consumes them. That is, only eat food every other day, but eat twice as much as you normally would.

There are several Crossfitters tinkering with IF, and most of them are reporting positive results (reduced BF, higher performance, etc.).

I, myself, do not alternate day fast, but attempt to compress all my food consumption to a 6-7 hour window. I like it, if for nothing else it means I spend less time eating (3 large meals instead of 5-6 small ones).

Brad-

You might have to ease your way into a fast of that length, but I have no doubt that you can do it successfully. Just be sure you don't reduce your calorie consumption, just the timeframe of consumption.

You can gain weight on IF. I put on around 10 lean pounds since the start of the year with an eating window of 9-10 hours. You need to eat a ton though (as you do anytime you want to gain weight). I was around 4200 cals a day. 6'4", went from 167 to 180 or so.

[Brad Kohler]

Thanks for your response Josh.
So you recommend a shorter fast and lengthen the eating time frame instead of 4-5 hours to 6-7?
Also what's your take on doing IF every other day or...only on every rest days in syn with the WODS?
Appreciate your advice brother,
Brad

[Alicia Zhuang]

Chris, have you or anyone noticed any difference in the effects of 15 to 18-hour fasts and 24-hour fasts?

[Chris Forbis]

Alicia-

I haven't consistently done greater than 18 hour fasts. I have recently gone from 14 hour fasts, where my last meal was about 3 hours prior to bed, to 18 hour fasts, where my last meal was 7 hours before bed. It seemed to be harder to get to sleep when it had been 7 hours since my last meal. That was the only real difference between the two.

It is worth considering to attempt the alternate day fast, especially because I have recently been working out on alternate days only. That might be something I will give a try.

Brad-

My gut intuition is that if you have just worked out, you are going to want to be eating so that your body has the necessary stuff to fuel/repair itself. So if you are going on the alternate day fast, I would keep the fasting to the rest day. I couldn't imagine doing a WOD and then not eating anything for 24 hours afterwards.

If you want to jump into a 4-5 hour eating time frame, go for it. I don't know how others have done it, but I eased my way from a 10 hour time frame on down to the 5 hour range. A lot of it will deal with willpower. Seeing as how you are 6-7% BF already, you probably have that and can deal with it.

[Matt Hulbert]

I'm not an expert on this but from what I read I thought you were supposed to work out *during* the fast so your body maintains its muscle mass.

If that's true you shouldn't fast on your rest day.

I've also read, though, that it's good to mix it up and not be too consistent with your schedule.

[Ragnar Speicher]

i came across an interesting article on the benefits of fasting:

"Professors Carlson and Hoelzel also demonstrated that, among some animals, maximum lifespan may be increased by 20 percent to 30 percent by intermittent fasting.3 Professor Sergius Morgulis of the University of Nebraska performed fairly exhaustive experiments for the time — 1920s. He demonstrated that while radical cellular changes occur, they are not impaired structurally. He pointed out that such fasted cells had the capacity for assimilation and growth which characterizes the cells of embryos and young animals, demonstrating beyond doubt that fasting rejuvenates.4



Professor Carlson spent many years investigating fasting and especially the mechanism of hunger.5 Dr. Margaret Kunde, who worked in the Department of Physiology at the University of Chicago with Professor Carlson, showed that a fast of two weeks temporarily restores the tissues of a man of 40 to the physiological condition of the tissues of a youth of 17. Dr. Kunde says: “It is evident that where the initial weight was reduced by 45 percent and subsequently restored by normal diet approximately one half of the restored body is made up of new protoplasm. In this there is rejuvenescence.”6"

"While regeneration of the body is a ceaseless process, rejuvenation is certainly not. It can be achieved only by fundamental and radical lifestyle changes. But fasting enables the body to abort the processes of degeneration and effect a higher standard of health. We must learn that the body is able to break down its structures, reuse and rearrange the constituents to bring about changes in quality of tissue. Fasting rejuvenates — the feeling, the look, the utility of function; an in-creased energy and capacity which is visible through the disappearance of many lines, wrinkles, blotches, pimples and pathological pigmentations; the skin becomes much more youthful and acquires a better color and texture; the eyes are clearer and brighter; one looks younger and more vigorous. The visible regeneration and rejuvenation of the eyes, skin and superficial tissues is allied to the evidence of similar but invisible rejuvenation throughout the body."

however this author does not quite agree with short fasts.

"In many cases men and women have been restored to sexual potency and fertility by fasting and in some cases after several years of dysfunction and sterility. Even repeated short fasts of two or three days have shown remarkable rejuvenating effects.2


Fasting one day a week

I am not an enthusiast of very short fasts; especially am I opposed to the practice of fasting one day a week. I think this is dangerous and positively inadvisable. During the first day of fasting blood glucose levels fall and glycogen reserves are depleted, the body then draws on its protein tissues to maintain glucose levels (gluconeogenesis). Subsequent to this adaptation is the utilization of ketones derived from fat and once this is established the fast will continue with its major source of energy being fat derived rather than protein derived. The short-term fast depletes body protein. During these adaptations you are losing protein. You have not reached the stage where you are using essentially fat, the properly adapted fasting state. So I personally believe that fasting one day a week is a very bad practice. Aside from that, one of the basic reasons for fasting is anorexia, loss of appetite. You go through the medical literature and you find in the major diseases, especially acute diseases, one of the first symptoms to arise is anorexia, loss of appetite the body is telling you unmistakably, “I don’t want food. Don’t eat.” As anorexia is the indication, it is hardly likely that every Wednesday or every Monday or whatever, you are going to be anorexic. You may have a roaring appetite but it is your fast day so, despite this, you abstain. Is this listening to what the body is telling you?"
http://www.healthscience.org/Article...on_article.htm

i dont know about you guys, but im far away from bein anorexic after a fast. rather the opposite. and everything is much more tasty as well ;-)

im not sure about the other stuff hes coming up with. ive heard before though that you get certain benefits of fasting only after 3 days onwards.

an alternative model to the if could be to fast, 3 or 4 days in a row each month.

another hard core fasting method ive read about is dry fasting which is said to have the double effect of normal fasting (that is one day of dry fasting counts as 2 days of normal fasting).

when you do a dry fast you not only dont eat, you also avoid any liquids. no water no nothing. you should avoid even showering, as your body will absorb a good amount of the water.

i havent tried this one yet but its supposed to be very potent. and from an evolutionary point of view there were probably also times where water was not abundant all the time.

[Yael Grauer]

Okay, just to throw a bunch of things out there on this topic:

I was trying to figure out the whole connection to cortisol to see if IF could lead to excess cortisol increase (over time) which would be a bad thing--I've looked at studies that showed negative effects of IF during, say, Ramadan (but they were all outdated with low sample sizes--I need to dig deeper.) But I read that IF causes increased insulin resistance, which should ideally keep the cortisol in check, only I was trying to figure out what was released when.

Then I found this article which indicated that the decrease in corticosteroid receptors reduces the effect of cortisol impact on the brain. So there's more cortisol but less effect on the brain. I need to find the original study (this guy's selling a book and diet) but his version of it is here:

http://chetday.com/warriordietantiaging.htm

I'll look in the archives again, but I'm curious at the exact #'s for people reporting lower BF, increased performance, etc. and whether they are relatively sure this is occuring due to IF and there aren't other variables. And also how long it took/takes.

The Warrior Diet (which I'm not recommending, btw--I hear you burn fat as well as muscle) is all about undereating during the day (light snacking on fruits and veg) and overeating at night (mostly protein), but this seems counterintuitive and not what cavemen would be doing. I just am guessing that since your cortisol is already highest in the morning, it would seem that this would be the best time to eat, work out, etc.

There's another book that recommends a feast/fasting cycle, which is called Natural Hormonal Enhancement by Rob Faigin. Cycling in this is more like weekly.

Also I was curious about moods for people doing IF. If I'm not eating regularly I get pretty spacey and irritable. I'm guessing people having positive effects from IF'ing aren't getting that reaction?

(There's an awesome article with a list of contraindications for IF'ing in the latest PMenu which just makes this SO much easier to sort through.)

[Heather L. Gibbons]

Couple of things:

Muslims traditionally break fast with dates followed by feasting. Dishes generally include a great deal of white rice. Sleeping patterns often change as well. With one or two large meals before bed and one large meal at dawn, meal spacing is completely different. Bottom line, I wouldn't look at Ramadan as a parallel model to IF.

National Hormonal Enhancement is cyclical but not a fasting model. It's carb cycling every 3 or 4 days with really low carb consumption otherwise.

Mood is great. Better than when I was just strictly paleo/zone. I'm less hungry overall and my energy level is better. I know the spacey and irritable thing but that was when I didn't have my carbs dialed in.