Sunday, April 17, 2011

Sweet Potato - A Primal Staple?

 As promised here is my sweet potato post. As my way of eating(WOE) continues to evolve(pardon the pun) along Paleo/Primal lines of low carb/high fat and protein I am aware of the debates regarding tubers online on blogs, forums and other medias.

 I tend to avoid white potatoes only because the are a member of the nightshade family and they do seem to disagree with me in terms of joint pain.I can enjoy the occasional white potato but there is definitely a personal "tipping point" that I dare not cross over.

http://rolfdevinci.blogspot.com/2011/09/nightshade-vegetables-harvest.html


Sweet potato is not a nightshade vegetable and, therefore, seems like an ideal food source, especially for post exercise recovery. That is important since I am making an effort to limit my consumption of sugary fruits which are part of my usual recovery food toolbox.



 A medium sized sweet potato baked in skin supplies about 24 grams of carbs, 2 grams of protein, 7 grams of sugar and 4 grams of fiber. Compared to the quantity of carrots and turnip I usually eat at any given meal the numbers are similar to those of a sweet potato. In terms of my net carb/sugar intake there is not much of a difference.

  The issue is whether or not sweet potatoes and tubers in general are paleo. Now let the records stand I am not a rigid adherent to paleolithic principles but acknowledge that tubers cannot be eaten raw.I also understand that there are some anti nutrient concerns* with potatoes.That said in an attempt to limit sugars(fructose) by avoiding fruits I will need to fill the void with other foods simply to offer myself some variety.

  It is controversal subject. Many hunter/gatherer societies have (and do) eat tubers. Applying logic to the debate it is not difficult to imagine chucking tubers on the ashes of a fire to bake or even burying them with hot stones/ashes in a paleolithic "oven" along with meats. The deciding point for me is that we humans produce amylase in our saliva and disgestive tract.....

"in overall form the human gut appears distinctly carnivorous, humans have one unusual feature for a carnivore: we have salivary glands that produce amylase, which has the the sole function of digesting starch. Since meat contains essentially no starch, this feature could not have arisen as an adaptation to an exclusive meat diet. It clearly represents an adaptation to starch consumption."

 Since tubers are essentially dietary starches it seems safe to assume that amylase production was an evolutionary adaptation to our consumption of starches, specifically, tubers.I don't see a stretch of logic thereabouts?
 Tubers are sourced over the globe in a variety of climates, are easily harvested, have decent open air shelf lives and are portable. The only question remains whether they were staples of ancient diets or more opportunist foods?

 I have begun to eat sweet potatoes as part of my WOE. Either as a post exercise snack quickly baked in the microwave with some butter, plain Balkan style yogurt and cinnamon or as a side with my usual staple - beef. There is something uniquely satisfying about having a steak and potato as if they were meant, by grand design, to be consumed together.



" think eating 15-20% of calories as starch is healthier than being VLC (very low carbohydrate) on only green veggies and meat. Starchy Plant Organs give you the most useful plant vitamins and minerals, spare your body the work of making your own glucose via gluconeogenesis, keep you out of ketosis, and keep your glycogen stores topped off, all while avoiding the antinutrients in grains. If you are fairly active, you might notice a big difference between 20% starch and 5%."
                                                                                                           Dr.K Harris

* Seems sweet potatoes carry a(relatively) low anti-nutrient load.....

http://www.food-info.net/uk/products/rt/spotato.htm

http://www.unilorin.edu.ng/publications/oladipofo/fin1435.pdf

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