The Real Paleo Diet? Cooked Starch, Says New Scholarly Paper

CarbohydrateInHumanEvolutionThe best diet is one based on plant food, with very little animal food. A large portion of that plant food should be starch. By starch I mean … all types of grains (rice, corn, wheat, barley, oats, quinoa), potatoes (all types including sweet potatoes or yams), starchy vegetables (peas, carrots, pumpkins and other squashes), beans, and legumes. But you know that.

If you’re eating this way, you’re eating closer to the way our human ancestors ate a million years ago. That’s what this new report says. (Thank you, Shaun.) What was the real Paleo diet? Cooked starch:

The Importance of Dietary Carbohydrate in Human Evolution, The Quarterly Review of Biology, September 2015

We propose that plant foods containing high quantities of starch were essential for the evolution of the human phenotype during the Pleistocene. … We provide evidence that cooked starch, a source of preformed glucose, greatly increased energy availability to human tissues with high glucose demands, such as the brain, red blood cells, and the developing fetus.

We also highlight the auxiliary role copy number variation in the salivary amylase genes may have played in increasing the importance of starch in human evolution following the origins of cooking. Salivary amylases are largely ineffective on raw crystalline starch, but cooking substantially increases both their energy-yielding potential and glycemia.

Regarding that second paragraph where they talk about “salivary amylase gene copy number variation” … Humans experienced an increase in the number of genes which code for the enzyme amylase right around the time they increased their intake of cooked starch. (We now have more copies of these genes than other primates, who don’t, to date, control fire.) Salivary amylase is secreted into the mouth when we eat. It breaks down starch. It doesn’t work well on uncooked starch, like the starch in raw potatoes. I blogged about this increase in amylase genes when it was reported in the journal Nature Genetics in 2007.

We hypothesize a gene-culture coadaptation scenario whereby cooking starch-rich plant foods coevolved with increased salivary amylase activity in the human lineage.

OldestKnownCookingHearthTelAviv2

This is the oldest known cooking hearth. It’s in Tel Aviv, Israel and is thought to be over 300,000 years old. – National Geographic
Hardy et al. write, “Suggestive evidence for an association between humans and fire is found in a number of early African sites … dating to at least 1.6 million years ago.”

Here are some kernels I found interesting:

  • Brain size increase was observed from about 800,000 years ago, from the Middle Pleistocene onward. That coincided with the increase in amylase genes, and the control of fire.
  • “Consumption of meat acted as a buffer against environmental change and to support expansion into unfamiliar environments. However, high-starch plant foods would have been a plentiful, reliable, and important part of the diet.”
  • “Humans are the only species that cook food.”
  • Starch was found in “roots, tubers, rhizomes, seeds, fruits, nuts, tree bark.”
  • Consumption of starch could explain differences in dentition between early hominins and African apes.
  • Forage in shallow water promoted bipedality.
  • “Postmenopausal females played a central role in foraging for USOs [underground storage organs, e.g. potatoes] and food sharing, which directly enabled younger female relatives to reproduce more frequently.”
  • Hunting by early hominins may have been as much to do with status as nutrition, something that has also been proposed for chimpanzees.
  • “The reduction in gut size is more likely to have occurred due to a gradual replacement of fibrous plants by higher energy-yielding plant foods, including starchy tubers.”
  • “It has been suggested that early Homo acquired the capacity for endurance running, considered essential to exhaust prey or outpace other scavengers in hunting. … The energy source for prolonged high level aerobic activity is an important consideration. Glucose is the only energy source for sustaining running speeds above 70% of maximal oxygen consumption.”
  • “There is a limit, considered to be 35–40%, to the amount of energy requirements humans can derive from proteins; above this ceiling protein toxicity can occur, which can cause death quite rapidly.” (Must get rid of protein’s nitrogen/ammonia.)
  • In the absence of dietary carbohydrate, or during starvation, gluconeogenesis alone is usually not sufficient. … There remains an absolute requirement for 30–50 g of dietary glycemic carbohydrate per day to fill the gap between gluconeogenic capacity and the brain’s requirement for glucose.
  • Tissue protein (muscle) is broken down out of necessity to provide the amino acids for gluconeogenesis.
  • “Although a very high fat intake will prevent protein toxicity and provide energy for metabolism, it comes at the cost of high levels ketones in the blood, which can compromise reproductive function.”
  • “Glucose is the main energy source for fetal growth.”
  • “Fruits and berries may have supplemented the diet depending on climate and seasonality, in particular by providing essential vitamins, but they are unlikely to have provided a consistent contribution to carbohydrate energy requirements.”

I doubt this will change the minds of people who like to eat a lot of meat, and who justify it somehow by saying our ancestors ate a lot of meat. They didn’t. Hunting and meat-eating were about status, or about getting us through hard times … snowy winters or droughts. Man evolved to eat cooked starch.

7 thoughts on “The Real Paleo Diet? Cooked Starch, Says New Scholarly Paper

  1. Melinda

    Thank you for this. I read tantalizing hints of this in various sources about the Paleolithic period over the last 7 or 8 years, but it’s great to have it all in one recent article!

    Reply
  2. Bix Post author

    There’s actually a lot of meat in this article. Like … women reached postmenopausal years? How old were they?

    This isn’t the first place I’ve read that too much protein stresses the kidney, that you have to contend with the extra ammonia. Isn’t this a concern for people who endorse high-protein diets? Diets that include animal food at every meal?

    I’ve always wondered about how our ancestors fueled themselves while they were out running for days on end stalking prey.

    Reply
  3. Sherry

    Hi I’m interested in knowing about this a bit more.
    I’ve been doing keto and I lift weights 4-5times a week, I consume protein 0.7gm per lb of lbm and I’m below net 30gm carbs, and I’m making rest of my calories up with fats I up them or down to either gain or lose.

    Now I feel very mentally good during studying for exams or at class, I’m like my mind isn’t foggy but truth be told, I hate eating tons of fats like coconut oil and cheese is very expensive here… Fats like grassfed butter and ghee are too expensive as well.

    Is there a way to maintain or keep muscle mass in a cut and be mentally very great like on keto, but using carbs? I believe you suggest a high carb diet.

    Eating carbs based diet in a deficit of calories makes me nuts… too hungry and energy levels bonkers easily.

    But will a high carb diet and low fat, in surplus of calories make me gain fat? As I read another article which says I won’t gain fat from eating excess carbs but excess carbs will be burnt off as energy.

    How’d you introduce the idea of eating starches to a person who’s Keto?
    How to feel mentally great and what macros do you suggest for the diet containing carbs?
    Thanks I checked the box for being notified via email, if you reply. 🙂

    Reply
    1. Bix Post author

      Hi, Sherry,

      I was moved by the openness of your comment.

      As you’ve seen by your experience, there is a trade-off for these diets, low-carb vs. high carb. While the low-carb, ketone-producing diet diet is effective for certain conditions, notably weight loss, I do not believe it is healthful in the long term. In fact, I think it’s harmful.

      A ketone-producing diet will have you burning fat for energy. It will make you look cut because you burn subcutaneous fat. Your muscles pop! The keto diet is used by bodybuilders before competition for that reason.

      But, as with anything, it’s not all benefit. There are costs to the low-carb diet:

      – Two of the three ketone bodies are organic acids (acetoacetate and beta-hydroxybutyrate). Having too many of them in the bloodstream upsets the acid-base balance. To protect that balance, the body excretes some of them in urine. But that makes the urine acidic and contributes to kidney stones.

      – When blood is more acidic, minerals from bone are used to raise its pH. There is a loss of calcium and other minerals from bone that can contribute to osteoporosis. Also, the calcium goes out in urine again raising the risk for kidney stones.

      – Low-carb diets are low in fiber. Fiber is only found in plant food.

      – Eating large amounts of fat and protein, especially from animal sources, increases the risk of several cancers. Add that to a low-fiber diet and there is an even greater risk for colon cancer.

      – Ketogenic diets, as this post notes, can compromise reproductive function. They can lower fertility.

      As you transition away from a keto diet and eat more carbs, you will begin to store more glycogen in your liver and muscles. That glycogen will grab onto water and hold it. So, there will be some water weight gain. This is not harmful but can be discouraging to people.

      These are just some of my thoughts. I’m not a doctor. I do like Dr. McDougall’s diet which is high in starches like rice, corn, potatoes, oats, beans; very low in fat; and virtually devoid of animal foods, including dairy.
      https://www.drmcdougall.com/

      Reply
      1. Sherry

        Thanks for the response admin Bix, I guess I’ll be doing Keto till I reach my ideal body composition goals and slowly transition back to including carbs like potato and oats.

        And yes I’m now aware of how carbs hold on to water, after a carb up (eating carbs at night and being low fat after being 6 days keto), I gained a lot of water weight.

        It was discouraging before to see the scale move up 2-4kg when I only ate 3000 calories max on carb-up lol.. so it made sense it was water weight.

        I’ll see Dr. Mcdougall but as I’m aware that even as low as 0.55gm of protein per lb was sufficient to maintain muscle mass (Tarnopolsky et all 1988).

        But wouldn’t Mcdougall’s diet be supporting loss of muscle because it hardly has any animal food?

        Btw regarding compromising “reproductive function,” isn’t that because most people who do keto would be eating in a caloric deficit, I mean if people do keto on maintenance calories they’d see positivity. Because as I understand in a caloric deficit the body isn’t well thinking about reproduction but surviving.

        Now if I’m going to do keto ans I want to avoid the issues you raised which comes with keto..
        Are these measures okay according to you?

        If I consume (as I currently am), 100gm of spinach and 50gm of onions, 7gm of chia seeds (soaked overnight in water), plus increased water intake with LoSalt’s consumption (it is a cheap way to get my potassium i add a tsp or two daily in my water bottle along iodized sea salt for electrolytes), daily on the keto diet, will I be having better chances of reducing the risk of colon cancer and kidney stones? As I’m getting my fiber… through alkaline veggies, also getting my potassium through LoSalt’s consumption.

        Regarding my openness haha..
        It’s always good to learn and be open, I in past did a vegan diet (with lentils sprouted for protein but got tired fast), I did low fat and low carb with high protein, then paleo low carb with moderate protein and moderate fat and finally keto with high fat and ultra low carb and moderate protein with a carb up every 1 or 2 week.

        Have you checked out Carb Backloading? It promotes consumption of high fat and protein in the first half of the day then carbs in the night after inducing insulin sensitivity in muscle through resistance training, the body is efficiently using fats and then at night carbs.

        Let me know your opinion on carb backloading and the Bulletproof diet by Dave Asprey. Sorry for taking so much of your time! Thanks :)!

        Sherry

        Reply
        1. Bix Post author

          Sherry, I just had a look at the Bulletproof diet. It isn’t something I’d advise for the long term. I wrote some thoughts about it in a post.

  4. Pingback: The Bulletproof Diet | Fanatic Cook

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