Intermittent Fasting: A Counterintuitive Brain Fuel
We’ve all heard the striking statistic that your humble brain, weighing in at just 2-3% of your total body weight, consumes almost a quarter of your energy expenditures.
For an organ that’s such an energy hog, it’s surprising to learn that cutting off your incoming energy supply — in the form of food — can offer significant benefits. But the brain is full of surprises and counterintuitive or not, the cognitive benefits of Intermittent Fasting seem to be real. (Animal studies certainly lend evidence in this direction.)
In Episode #120, I speak with Dr. Mark Mattson, a neurologist at Johns Hopkins University and the National Institute of Health (NIH) about his decades of work in the fields of nutrition and brain health, and the complex interplay between diet, exercise, “feeding windows” (we’re not talking McDonald’s drive-thru), and macronutrient ratios.
Studies are still ongoing — more aggressively than ever — in all of these fields. And while much remains unresolved, there is also a lot that we do know. Listen in to learn Dr. Mattson’s take-aways that he has used to form his own health and lifestyle choices, his thoughts on when animal models may be reasonable to act on, and when more research is still needed.

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Show Notes
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00:00:36
Caloric restriction and cognition
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00:01:20
This Week in Neuroscience: The woman who looked at faces and saw dragons
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00:04:58
The audience interaction section
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00:07:32
STEMtalk by The Florida Institution For Human & Machine Cognition
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00:08:23
Introduction to Dr. Mark Mattson
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00:09:08
How exercise and fasting affect cognition
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00:12:21
Regular glucose metabolism and how this changes while in ketosis
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00:14:23
Relative effects on cognition of fasting, intermittent fasting, and high fat diets
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00:16:14
Dr. Mattson’s own dietary choices
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00:18:14
Caloric restriction and longevity in animals and humans
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00:20:58
Strength, survival rates, and caloric restriction
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00:23:12
The importance of the intermittent nature of stimuli
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00:26:53
Protecting the brain against Alzheimer’s disease
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00:29:42
General upsides of intermittent behaviour
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00:30:43
Rhythms of the body
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00:31:55
Is anyone lobbying the National Institutes of Health?
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00:34:39
Obesity as a disease
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00:36:19
Phytochemical hormesis
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00:37:20
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00:37:46
Ruthless Listener-Retention Gimmick: Photographing the glow of the human body
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00:41:14
RE: the two days of semi-fasting (500 calories), can I do one on a Monday and the second on a Friday or do they have to be consecutive days?
Great question, and no — they don’t need to be consecutive. In fact, I’m pretty sure they are supposed to be non-consecutive, so lucky you. 🙂
Is it ok to take supplements(specifically, fish oil, ALCAR, mushroom extracts, bacopa, ginko, COQ10 and D3) during fasting days?
Short answer is “yes,” but the longer answer depends on what you’re trying to get out of fasting, which can have a variety of benefits. Especially for things like weight loss, speeding the entry into fat-burning metabolism, etc., reduced-calorie diets (like the very small amount of calories found in a handful of supplements) are no big issue. The “Fasting-Mimicking Diet,” for example, replicates many of the biomarker effects of a full acaloric fast while allowing a significant (although significantly reduced) amount of eating per day.
On 3rd day of a 3.5 day fast, and performed HIIT with a heavy rock which I support above head with my arms. I suddenly had more energy and stamina today..amazing stuff.
“Starving Man Hoists Big Rock!” — needs a photo. Hope that you had someone grab one. 🙂
Great article. I just stumbled into intermittent fasting by accident.
It took about a year of reducing the window during which I eat, to get me to the point where I now eat only between 12 noon and 8 pm.
Of course I started by just skipping breakfast. I always do about 1/2 hour of cardio in the morning, plus body weight exercises (pull ups and pushups)
The only day i lack energy is Sunday on which social protocol requires me to eat breakfast.
I think I could actually eat only one meal a day if I wanted, but I’m almost as thin as when I joined the Navy at 18, and at my current age of 57 I really don’t want to lose muscle mass.
Thanks for writing, Levi. I’ve been on a 7-hour eating window for most of the last 3-4 years also, a bit later — 4pm to 11pm, so I can still get in a dessert before bed. 🙂 But I agree that this works great for my alertness throughout the day (something I never would have guessed having grown up on all the “breakfast is the most important meal of the day” talk). Occasionally I’ll splurge and have some pancakes made from eggs+bananas for breakfast, but there’s always a bit of sluggishness-hit when I do.