waywardsister
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IF and mental clarityFrom Art DeVany's blog
| Quote: | I often hear people say that some degree of fasting clears and sharpens their mind. I heard it a lot when I attended the Calorie Restriction Society meetings and a reader now and then says the same thing in a comment on the blog.
I don't know that there is much study or evidence on this point, though I think there are reasons why a sharpening of the mind occurs during intermittent fasting.
1. Hunger does concentrate the mind. An ancestor who got lazy or fuzzy minded during caloric deprivation would have poor survival prospects. There are studies that show that subjects who undergo food deprivation become focused on food, even obsessed with it. The more gentle, intermittent fasting with eating to satisfaction following, is unlikely to promote the obsession. Still it may better focus the mind, though the focus can be too single minded to realize the benefits of the focus in your work.
2. Fasting releases HGH which, in turn, makes muscle more insulin resistant. This spares glucose for the brain. Thus, energy may be more favorably shunted to the brain by fasting. Moreover, the stomach competes with the brain on more or less equal terms for energy; they are rough metabolic equivalents in energy use. Fasting reduces the stomach's intake of digestive energy making it available to the brain. I think also that the brain is the last organ to become insulin resistant; thus fasting might relatively increase brain sensitivity.
3. At some point during the fast, the brain may switch to ketones as an energy source. I recall reading of the benefits of glucose to ketone cycling as energy substrate.
When there is a surplus of energy, the body's purposes are more diffuse, less purposive and reproductively oriented. When there is shortage there is a wonderful focusing on staying alive; repair and maintenance take precedence. |
Comments:
| Quote: | Don't know if this has been mentioned before, but Conditioning Research blog had an entry on fasting and recommended two online books, Fast-5 and Eat Stop Eat. I got through each in under 2 hours. The first is free, the second is a purchase. I found the second one far more valuable and the recommended program (one to two 24-hr fasts per week) roughly corresponds to what I already do (one to two 30-hr fasts). According to the research he cites, fat burning really kicks in at 18 hours in maintains a high rate, and then begins to taper at 30 hours.
So, if you're still focussed on ridding fat as I am (rather than maintenance), two 24-30 hour fasts per week without trying to make up for the calories might be called for. It seems to be working for me.
Also interesting was research cited where subjects who had fasted for three days showed no signs of diminished strength when performing a workout. Seems intuitive. Evolution would have favored those who could go long periods without food and still hunt with all their skills and endurance intact.
Anyway, chalk me up as another one who thinks that incorporating fasting is really a fabulous icing on the EF cake. I can't think of one negative aspect, and I'm even getting to where I find the mild hunger strangely pleasurable.
Oh, here's that post at Conditioning Research with the links to the online books:
http://conditioningresearch.blogs...ittent-fasting-helps-diminsh.html
Posted by: Richard Nikoley at December 28, 2007 6:34 AM
I love fasting for the concentration, but there may be another reason: in biology we were taught that after about 8 hours of fasting, the body releases opiates. I think this is why the warrior diet was so addictive.
Posted by: Conan at December 27, 2007 10:30 PM
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http://www.arthurdevany.com/2007/12/mental_clarity.html
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adwred
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I definitely find that is true of fasting or under-eating - the increased concentration. It can even be sort of euphoric at times.
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ReddyMcMeaty
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me too
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Carnation
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I fast fri night thru sun morn BECAUSE sat is my heaviest work day. I feel as if the fasting gives me more of a mental edge. By my afternoon apts, I really feel I'm at my peak focus.
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