Carbohydrate Shortage in Paleo Land: New Data for A Scientific Outlook at the Low-to-No Carb Paleo Confusion. Will More Than 125g of Carbs Make You Fat?
|Image 1: Salmon, one of the few foods,|
even the extremists allow themselves
(photo by Dezidor)
Oh, before I forget. This is not another pro- or anti-paleo carb or paleo blog, but the SuppVersity - so let's try to tackle the low-to-no carb conundrum from a somewhat more scientific perspective. Only very recently Alexander Ströhle and Andreas Hahn (Ströhle. 2011) have published a paper in Nutrition Research, in which the authors take another, closer look at the purportedly low carbohydrate content of THE paleolithic diet. In that their most relevant finding unquestionably is that the "diets of hunter-gatherers showed substantial variation in their carbohydrate content". So, even if the ludicrous assumption that the way our ancestors ate would be the "optimal" way to eat for us held true, we still would not know whether this "optimal" diet would contain <3% or >50% of our daily caloric intake in the form of carbohydrates, for these are the variations Ströhle and Hahn found for different ecoenvironments.
|Figure 1: Average minimal and maximal carbohydrate content of the diet of paleolithic individuals living at different latitudes; data in %-age of calorie consumption (based on data from Ströhle. 2011)|
|Figure 2: Recommended (mean) carbohydrate intake in %-age of total calorie consumption |
(data adapted from Ströhle. 2011)
But let's put this hot topic aside and get back to the issue at hand and ask our selves: "How low-carb was the paleo diet, then?" Well, 22% of a 2.000kcal diet would still be 440kcal, which is equivalent to 110g of carbs, which is at the upper end of the low-carb continuum (ranging from 50-130g of carbs per day), as it was proposed by Accruso et al. (Accruso. 2008) and that is far from no-carb or recommendations <80g, where it becomes increasingly hard to find nutrient dense foods, the sum of which would not exceed your daily carbohydrate limit. Maybe I should add, that it is by no means accidentally that the limit appears to be somewhere around 500kcal. A 1988 overfeeding and depletion study by Acheson (Acheson. 1988) reports that "an average male human being canaccommodate a gain of approximately 500 g before net lipid synthesis contributes to increasing body fat mass". So even within the upper ranges (and without exercise!) you are way below the fat storage zone. Under circumstances of continuous glycogen depletion such as exercise training, which go hand in hand with severe muscle and liver glycogen depletion, you may well be able to tolerate much higher amounts of glucose, because overall, your body is able to store roughly 5 g glucose per kg of body weight. So, once carb-depleted (notice: 100% carb depletion is a state you will not achieve; probably not even by running a marathon) an 80kg human being could safely refuel on 400g of carbs or 1.600kcal without running the risk of overloading his glycogen stores.
All these arguments aside, it is also noteworthy that the restriction in carbohydrates, our ancestors practiced, was by no means self-inflicted, it exhibited great seasonal varieties and there is NO proof whatsoever that a higher carbohydrate intake - of course in the form of those whole foods that were available to the paleolithic individuals - would have made them more susceptible to "modern disease" - but this would be whole other blogpost. And let's be honest without your highly processed breads, cakes and pies, your high-fructose corn-syrup laden sugary drinks and all the pasta, pizza and rice the restaurants serve in order to keep you from noticing that they economized all the expensive stuff such as meat, vegetables and fruit, you probably would not even get beyond the 35%-margin Ströhle and Hahn identified at the maximal (seasonal mean) carbohydrate intake in across various hunter-gatherer populations, and latitude and ecological environments. And isn't it ironic, that the very sweet tooth that kept our ancestors alive, is killing us today.