Posted by: SLS | January 17, 2011

Stoking the furnace to keep the fire alive

To be completely honest, I had expected my discussion about muscle activity to eventually roll into a broader talk about metabolism sooner or later. It’s not a point I intend to drive home necessarily, but I think there’s a lot of relevant connection between the metabolic response to food and the metabolic actions of our muscle tissue. However this post does come a little bit sooner then than I had hoped, but it seems to be an appropriate time in the general omniscient wave of collaborative circulating thought to discuss the heated back and forth about adequate or responsible carbohydrate consumption.

There are essentially two camps with lots of gray in between. One camp believes that carbohydrates should be (severely) restricted while the other maintains that carbohydrates are a vital and necessary component of human diet. In these two extremes, if we were to ascribe a macronutrient percentage range to each, the low carb camp would be around 10-15% of total daily calories and the high carb anywhere from 50-70%. The low carbers include Paleolithic nutrition, Atkins, Weston Price, Primal nutrition, and Evolutionary Fitness nutrition. The higher carb camp (or just carb proponents) include the USDA, ADA, AHA, most modern nutrition science education and educators, the fitness and personal training industry, and the conventional wisdom of the majority of Americans and perhaps other Westernized nationalities.

When I first began to explore the former camp, I largely found an anti-carbohydrate sentiment with the idea that carbohydrates are what stimulate the aging cascade in our body, therefore we should restrict carbohydrate consumption to low glycemic vegetables and fruits while consuming fat and protein for the majority of our calories. This means that grains, legumes, beans, starchy tubers and sugar are all to be avoided because they promote inflammation, auto-immune disorders and metabolic syndrome. While the effect of this on human diet in modern times remains to be substantially explored over the lifetime of individuals, we can say with great certainty that low oxidative stress and inflammation (read: insulin/IGF/free radical) are a fountain of youth. The work done on nematode worms by researchers in the late ’80’s and early ’90’s (Cynthia Kenyon, DB Friedman) really jump-started this exploration into the age defying effects of low auto-immune stress, particularly from restricting glucose consumption. In essence, these little worms experienced a sort of suspended animation that extended their lives to twice what they were when fed glucose. How nice that must be. Other evidence ranging from prehistory reconstruction to ethnographic research; from the lab to the anecdotal, is also painting a similar picture of the life-extension propensity of low oxidative stress and inflammation inducing environments in humans, dolphins, birds, tortoises, and even domestic cats.

However, lately, there has been a very interesting and potentially necessary rethinking of the earlier carb-phobic strategy to weight loss and healthy living. In particular, where the cry was once “go as low you can go” with regard to carbohydrate consumption, now it is more “not all carbs are bad, we can and should tolerate a bit of carb in our system, don’t be so extremist.” Notable voices in this new approach include Robert Lustig (who has actually always crusaded against fructose and never really demonized all carbs), Art De Vany, Mat Lelonde, Robb Wolfe, and Loren Cordain. I’m sure there are more but those are the names that come to mind from my latest readings. Surveying the message boards of other low-carb/Paleo styled interests shows a similar trend of acknowledgment towards the potential necessity of carbs.

I am writing here today wondering why.

And I believe the answer is a bit philosophical. Every living organism balances a fine line between maximizing self preservation and survivability with reproductive success. The nutrients we consume are constantly telling our cells what the outside environment is like. The simplistic description is a dichotomy: there is either feast or famine. A signal for feast is a signal for growth, maturity, and reproduction. A sign of famine signals maintenance, repair, and conservation. The organism either spends freely or conserves resources. The environment is saying either grow, proliferate and enjoy this wonderful bounty, or it is telling us to save ourselves, buckle down, hold out for an unknown amount time until the famine lifts.

Can you see where this is going? The fountain of youth is nothing more than a resource recession, while the rock-star life of no restraint is nature’s bacchanalia. Why do these signals act this way? Because in the unpredictability of the natural environment, evolution has awarded success to those species who can best utilize resource when it is available. If the environment is rich, then it can support reproduction and the needs of future offspring. If the environment is poor, then it is an unsuitable time for reproduction and the organism should preserve itself until a better time. The strongest signal in this resource seesaw is glucose availability, or carbohydrate. The rarest or most unpredictable macronutrient in nature is carbohydrate. It comes in fruit, flowers, nectar, honey, starchy underground root vegetables, and mother’s milk, all of which are seasonal, ephemeral, and rare. The other source of carbohydrate from seeds, grains, nuts and vegetables are locked away inside insoluble fiber or protected by toxic anti-nutrients. So the availability of carbohydrates, since normally scarce, induces a powerful signal and organisms have evolved a similarly powerful response by way of the insulin/IGF pathway for growth and storage. This pathway allows us to grow and develop from infancy to adulthood, so it is absolutely vital, but its beneficial aspect comes into question when over expressed. Insulin/IGF is also implicated in cancer growth and Alzheimer’s as well as auto-immunities, senescence, old-age and death. On the one hand, insulin/IGF gives us life and allows us all manner of adaptive phenotypic variation but the double edge is that it is also part of our metabolic demise.

With our mortality in mind, I wonder if there isn’t sort of an esoteric appreciation for the thrilling and adrenalin producing aspects in life? Perhaps, in effect, life extension through carbohydrate or even calorie restriction to an extreme degree is sort of like that cryogenic freezing state we learned about in Space Odyssey. It may preserve life but then how well can one live without that little life spark, burning like the pilot light in a gas stove; passively lit, almost unnoticed, but ready to blaze at the slightest provocation? And that’s almost exactly how inflammation is described. It is like an inward furnace, stoked and ready to burn the long out of longevity, but simultaneously guiding the processes that constitute life.

In this sense, we can’t completely ignore the fuel for our fire, even if too much will kill us. Perhaps that is why the outspoken wise men and women don’t completely condemn carbohydrate and glucose, only the the majority of its modern manufactured sources. Maybe there’s no coincidence that our metabolism runs on glucose first, then lactate, and ketones. And death is just an assurance that we lead fulfilling lives.



  1. This latest article is one of the best explanations of the carbohydrate issue and the various camps on the impact and need for or lack thereof of carbs in our diet. I look forward to more from you about this debate.
    From reading DeVany’s book, I had the impression that he was in the extreme camp, contending that all foods from grains contribute to most of the prevalent diseases of modern life. You placed him in the moderate group regarding including carbohydrates in our diet. Are you considering his views that nutrients from fruits are necessary even though fruits are high in sugar?

    • I think I could have made that a little bit more clear as there is a distinct difference between someone like De Vany and someone like Atkins, and while their philosophies are the same, their strategies for weight loss and health are notably different. De Vany certainly makes a point of demonizing carbohydrates, but he does not become obsessive about it, nor does he want to eradicate them completely, only portion them into sparse amounts from natural sources tolerated by the liver. Robert Lustig makes a specific point about carbohydrates becoming toxic only when their absorption from the small intestine is faster than can be metabolized by the liver. Taking a step back from toxic, we have, potentially, “irritating” and inflammatory promoting which is the level that De Vany and others seek to avoid. However, to be below inflammatory is to be about under 100g of carbs per day, from whole foods where the fiber is intact, and for it to constitute a relatively small percentage of your total daily calories (10-15%).

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