[Tip: if you're not familiar with hormesis, check out this page from Todd Becker to get a quick intro. Basically, the idea is that exposure to a little of something causes our body to respond in a way that can be healthful for us (e.g., vaccinations), while a lot of exposure can be harmful.]
If you want to take a listen, check out the podcast (link above) starting at the 30:53 mark. But I’ve gone ahead and transcribed it for your reading pleasure (I’ve made only minor edits for readability’s sake):
Robb: Joe says, “I have a question concerning your last post on your blog (which was back in February). I’ve always been under the impression that the brain could run efficiently on ketones, but in your post on carbohydrates you unequivocally state that glucose is necessary for optimal brain function. Am I mistaken in my belief that you do believe that ketosis is dangerous for brain function? How would you situate ketone bodies in your classification of fuel?”
KGH: The thing to know is that the brain requires glucose in an obligate fashion: meaning it’s not an option. The brain has to have glucose. Where ketones come in is that, instead of having it be all glucose you can substitute — I don’t know what the number is, 50 or 60 percent let’s say — of the energy requirement can be made up of ketones. That’s an adaptive response to starvation. To the degree that being on a very low carbohydrate diet or constant ketosis all the time … I’m going to take a tangent here that doesn’t directly answer the question. …
We just got done talking about hormesis. This answers the question when people say “Why don’t you think you should be in ketosis all the time? If ketosis is good for you, why shouldn’t you stay on a ketogenic diet?” Because it’s hormesis.
It’s hormetic to be in ketosis. It’s probably hormetic to do intermittent fasting, it’s probably hormetic to have reduced meal frequency or go 16 or 18 hours every day without a meal versus snacking. That’s probably hormetic. Taken to extreme, it’s called Auschwitz. It’s called starvation. That’s the extreme of not eating.
In the same sense, I think ketosis is good for us to do once in a while. It’s something that naturally occurred during our evolution occasionally. I don’t buy the thrifty gene hypothesis, but periods without food were not that unusual, so it’s logical that that might be good for us. But staying in ketosis all the time is not good for us just because some ketosis is good for us.
For me, this neatly fits with what I briefly mentioned in my previous post: the value in cycling carbs seasonally. What could be more natural from an evolutionary perspective?
What the heck does this have to do with bisexuality?
Well, I’ve been thinking recently how taking a moderate position on carbs is like being bi — it can be hard to be “out” about it, as it’s a polarizing issue and frankly, folks push you to take a side.
I’ve been thinking about the parallels recently because one of my political reads pointed to a recent study showing bisexual men exist (trust me, I’ll get to the point soon):
Despite enormous strides made in the past decade for LGBT rights, male bisexuality remains a challenging idea and a unique taboo, even within sexually progressive circles.
A large part of that is because, culturally, we tend to think in terms of black-and-white, not shades of gray — and that’s especially true when it comes to the subject of sex. Rarely does a bisexual come out without fielding questions about which sex they like more — the assumption being that they must lean one way or the other.
So really, no matter where you are on Kinsey’s scale, consider the similarities to the current discussion of macronutrients in the blogosphere and elsewhere. If you want to turn up the heat, just get into a discussion about the idea macronutrient composition of a healthy diet — and try and argue a middle position.
Like the LGBT community, the LC community have their identity pretty staked out. So just as the bisexual man is a “challenging idea” so too apparently is the idea of more moderate carb consumption.
Funnily enough, Dr. Mike Eades (of Protein Power fame) provided one such example today on Twitter in a conversation with Chris Kresser. Here’s a snippet (edited slightly for readability):
Dr Eades: Carbs in the diets of most hunter-gatherer societies were markedly different (lower) than amounts currently recommended http://t.co/opWgWZg
Chris Kresser: That study also said “diets of hunter-gatherers showed substantial variation in their carbohydrate content”. From 15-35%.
Dr Eades: The paper doesn’t give us a clue about carb tolerance; it merely states what the various groups consumed.
Chris Kresser: Modern HG have low rates of CHD, obesity, inflammatory disease, so we can assume they tolerate up to 35% natural CHO fairly well.
Dr Eades: Remember Bastiat’s parable? You’re falling victim to That Which Is Seen. You know nothing about That Which Is Not Seen.
The last point is one that Dr. Eades made in his AHS11 presentation: according to Eades, just because some groups appear to tolerate carbs doesn’t mean that they wouldn’t do better without them.
Well I suppose. However, to me, this just doesn’t fly given what we know about evolution or physiology.
If you listen to the podcast, Kurt goes on to answer the question about ketones and the brain. While part of the brain does quite well on ketones, it still requires some glucose. So ketosis is an adaptation that enables the brain to preserve glucose stores — the body’s lean body mass — in a time of starvation.
For me, ketosis as hormesis makes sense. Eat sufficient carbs (Paul Jaminet suggests 400-600 calories, which is interestingly, Mark Sisson’s “effortless weight maintenance” range) most of the time with some low and high carb periods for variety.
Works for me!