Welcome all seeking refuge from low carb dogma!

“To kill an error is as good a service as, and sometimes even better than, the establishing of a new truth or fact”
~ Charles Darwin (it's evolutionary baybeee!)

Wednesday, June 8, 2011

A Common Sense Case for Starch

We discuss a lot of science here and for a change of pace I was thinking the other day about why I think humans were meant to consume starch for at least a goodly portion of our energy.  I'm not going to talk about obscure cultures most of you never heard of and Americans and most cultures around the world have never eaten like.  I'm not going to talk the minutia of evolution, genetic adaptation, extinct fauna, etc. etc.  

I'm going to talk look at that body of yours.  Clearly we've evolved or adapted or whatever over the centuries to eat both plant and animal foods.  Look at your mouth for starters.  And now look at the kitty's mouth below.

I don't know about you, but when I compare my smiling mug to this fella, I don't see a lot of similarities.  This fella is a carnivore.    Kit cat here has teeth designed to rip into flesh and not so much for chewing.  I, and you, on the other hand don't possess particularly fang-like canines and we've got large flat molars.  

But I'm not done with the mouth yet.  Digestion begins in our mouths starting with amylase to break down starch.  Kit cat up there has no amylase because kitty is a carnivore.  So why do humans have salivary amylase?  Perhaps it's as simple as that we're designed to consume carbohydrates.

OK so let's fast forward all the way down the digestive tract through the small intestine.  We clearly have nothing in common with herbivorous ruminants so we can ignore them, but what of other omnivorous creatures?  Enter the hind-gut fermenter.  Of course we can't use the mirror for this comparison so I'll have you compare the digestive systems below.  For this comparison, let's take a look inside this cute fella.  

And let's compare that to the human digestive system:
As you can see, the rabbit is a hindgut fermenter, humans are not.  The cecum is a functional organ in the hindgut fermenter, it's more an area/region in the human digestive system.  Indeed our appendix is thought to be by many our true equivalent to the cecum.  The purpose of the cecum is so that species so equipped retain material - cellulose and soluble fibers and such - wherein bacteria can breakdown such fibers to extract usable energy for the animal.  Interestingly enough, such animals will also often engage in coprophagy to gain access to nutrients that might otherwise go wasted.

Long story short, does it seem that humans are well suited to eating non-starchy vegetation for energy?  I think when we approach this whole notion of the best diet or a healthy diet, too many of us do so from the starting point of weight loss rather than true health and optimization.  Since the first time I started reading Mark Sisson's blog, I always wondered about this notion that our primitive ancestors would somehow expend energy to forage for the foods with the highest fiber content and lowest starch content.   My common sense says to me that plants have been storing energy as starch for a very long time in the history of this planet we inhabit.  My common sense also tells me that if hindgut fermenters can have the smarts to eat their own feces - can't be too palatable if you ask me - to extract energy, we humans certainly learned quickly which species of plants provided us with the most energy and tended to eat those.  Which is not to say that we probably didn't eat a lot of fiber along the way in our quest to fuel our bodies, but we were seeking the starch (and sugars).

Common sense tells me that a diet of mostly meat and green leafy vegetables is not optimal for fueling the human body for the long haul.  This is not to say such a diet doesn't have its place in the treatment of certain conditions, obesity included.  But this blogger is coming to the realization that starch is a natural human food  that our bodies are "built" to use for energy.

Unfortunately in our modern world, starches have been refined like sugar.  On their own, neither is all that palatable, starches - especially refined - are actually the least palatable food I can think of.  So we humans started combining them with sugar and fat.  Welcome to the cafeteria ...


Melissa said...

You might be interested in my colon series

besides some adaptations in the colon, we have variation in salivary amylase genes that seem to be adaptations for starch. Wrangham's Catching Fire is a good read, I do disagree with him though on the time span on when starch became important to humans. I think that happened quite recently, he thinks it's very ancient.

Diana said...

Hi CS,

As usual, very illuminating in a common sense way. Regarding what we evolved to eat...I think that we evolved to eat anything that doesn't poison us or severely upset our digestive systems (like grass). Other than that all bets are off. The Aborigines thought that witchetty grubs were a delicious delicacy, esp. for children and pregnant women:

I cannot overcome my disgust at the thought of eating grubs, but I've read that they are custardy and sweetish.

Aboriginal women used to spend a long time foraging for plants that could be baked into bush bread:

When the white man came these switched to making a white flour quick bread called damper:

It's been all down hill for Aboriginal health since then.

My point here isn't a political one about bad treatment of an indigenous people (that's for another blog) but to point out the intersection of what people evolved to like. And people also evolved to like convenience. It's not fun gathering plants for hour after hour. I don't think you can get Aboriginal women to forage for hours for the ingredients for bush bread.

Tonus said...

An issue I have had with the notion of 'eating like our ancestors' is that they generally seemed to be at the mercy of their environs. It does not seem to me that they had the luxury of being picky; you ate what was available. Agriculture probably seemed like a godsend. Sure, there may have been unforeseen issues with a grain-based diet, but the dangers inherent in confronting an angry (and exceptionally large, in some cases) creature and trying to stab it to death probably were a greater concern.

Diets for ancient man seemed to vary considerably IMO. We learned which foods would kill us quickly, and over time we're learning which ones may kill us slowly (and then, for some reason, creating dietary guidelines promoting the latter!). I think it confirms my belief that we cannot take shortcuts for ourselves when it comes to diet and health; we must find out what works best for us as individuals.

I can admire paleo-man, he had to fling a spear at a sabre-toothed cat and then wrestle it into submission if he wanted to eat. His lifestyle has little appeal to me. Maybe his diet should as well?

Malcolm Klein said...

Since around 1.8 million years ago we were forced to move out of the rainforest onto the savannah, and we didn't leave Africa until around 80,000 years (or 0.08 million years), 96% of our prehistory was surviving in a tropical grassland environment- not many fruits and vegetables... Richard Wrangham's theory that we were forced to use underground starchy tubers and roots for survival fall back foods, with hunted/scavenged meat being a valued but more infrequent source, makes a lot of sense... yet people persist in thinking of paleolithic as all about big game hunting in ice age northern environments!!

Check out these links...

Popular “Paleo” Diets Have Starch-Phobia

Many of the popular Paleo diets teach fear of starches. I don’t have to name them – if you’ve read a Paleo diet book or been around the blogosphere, you’ve probably learned to think of fruits and vegetables as the only true “Paleo” plant foods.

But Human Ancestors Relied on Starches – Especially After Inventing Cooking

Anthropologists believe that ancient hominins 2 million years ago, including Australopithecus – probably not our direct ancestor, but more closely related than chimps or gorillas – ate starchy tubers. The digging stick had been invented, and in-ground tubers were an easy source of calories.

Starchy foods tend to have a lot of toxins, to discourage animals from eating them. However, the toxins in tubers, rhizomes, corms, and bulbs are mostly destroyed by cooking. Cooking also makes starches more digestible. Thus, the invention of controlled fire and cooking must have made starches into a dietary staple.

Richard Wrangham in his book Catching Fire: How Cooking Made Us Human argues that the invention of cooking occurred 1.8 million years ago, and that cooked starches fueled the rapid growth of our ancestors’ brains.

Margaret said...

I also like Robert Lustig's argument that starches are made up entirely of glucose subunits, as opposed to sugars such as sucrose, which is a disaccharide made up of glucose and fructose. The body clearly has pathways set up to utilize glucose, whereas fructose has to be metabolized only in the liver just like toxins or drugs, i.e. it isn't perceived by the body as something necessary. I've always believed it is natural for humans to eat starch, and was puzzled by the move against bread and potatoes instead of just demonizing simple sugars. One problem with bread is that most commercial bread is very sweet so it's hard to get the starch without the sugar - I bake my own! I've also wondered if regular corn syrup, as opposed to HFCS, is simple glucose and therefore may be a better choice for those who like such things? The Caro bottle just says "corn syrup" so I would assume that is glucose, since corn starch is a polysaccharide made up glucose. But it's also clear that overconsumption of glucose is going to lead to obesity as well, just maybe not NAFLD (directly, anyway)!

Jeff Borsato said...

another great post carbsane,

the question is a complex one and no doubt a forager concerned with expending most of their calories to simply find more food and feed their family learns over the course of generations which foods maximize energy and minimize output.

it makes sense that we eventually settled in crop rich agricultural based socities as they provided a steady and reliable source of food that foraging and wandering may not have, or at least may not have provided to those anything less than strong or healthy enough to follow buffalo around the plains or hunt wild game.

modern starchy foods like pasta and mashed potatoes bear little resemblance to foraged starches like potatoes or tubers eating most likely plainly cooked without added sour cream, bacon bits, butter, or bolognese sauce.

our evolution may have allowed for starch consumption, but it is a very different matter to ask if we evolved to consume a lasagna.

but theres nothing wrong with doing things that we may not have evolved for if you enjoy them, the question is why you enjoy something so much and if that pleasure becomes toxic. i enjoy scotch, if my enjoyment led to alcoholism the question should be less one of "how much" and more one of "why?"

food is a fairly accepted addiction in our society, no matter how much scorn is reaped upon the obese or unhealthy, no one is shunned for eating a tray of brownies unless if was for the kids and your spouse worked really hard to bake them even though you specifically told her that you cant control yourself around baked goods!!! dont judge me!!! ;)

Charles L. Peden said...

I wasn't too sure what paleo diets were trying to do. It sounded incorrect enough that I just never looked into it. Evolution works much faster than most people expect. Significant changes can happen within a few generations.

Here is an interesting discovery that was made about the gut of Japanese people versus North American. Right now there are probably people who are evolving to better adapt to the SAD. Keep in mind there are people who could not adapt to the SAD diet that will not be making babies or posting comments on this blog.

Charles L. Peden said...

Oops, here is the article:

MikeEnRegalia said...

Nice post!

But we're obviously true omnivores. Comparing our teeth to felines is an inherently vegan stunt - I hope you're not deducing that because we don't have feline teeth we shouldn't eat meat.

My opinion about our optimum nutritional profile: Lean meat (preferably seafood), starchy vegetables (tubers, roots) and the occasional fatty treat (animal-based). This is based on latest findings from South-Africa, where human dwellings were found that date back almost 200,000 years. They're near the ocean and there's an unique flora and fauna that strongly suggests that starchy tubers as well as seafood were staples in the human diet.

What we're in agreement with is that a diet constantly high in fat and low in carbs is most likely not optimal for most eople.

Malcolm Klein said...

Sorry, evolution works slowly over hundreds of generations, so the key is the generation time. Bacteria, for example, can evolve resistance to new antibiotics quickly because they reproduce every 20 minutes!! Thus a month equals 2000 generations!
Humans, with a 30 year generation time means that there have only been 200 generations since the widespread adoption of wheat and rice, not enough time for more than a few minor changes, like for example the single mutation changes that allow some populations to now digest the lactose in milk into adulthood.

The paper about the Japanese was talking about a gene for an enzyme that digests seaweed being transfered from a wild ocean bacteria to bacteria like E coli that live permanently in you gut. That happens all the time- gene transfer from bacteria to bacteria- there was NO change in the Japanese's own human genome- ie. no human evolution in that case!

A minor quibble re "it makes sense that we eventually settled in crop rich agricultural based socities"
- Humans didn't "adopt agriculture" because they saw it was a "better" life- Some populations were "fortunate" to live in local environments rich in wild grasses and grains after the retreat of the glaciers of the last ice age, and so reduced their wanderings and became more sedentary- THEN, with the increased calories, their populations grew, expanded, and gradually spread out pushing out the local hunter-gatherers, a process that is still going on to this day. Very few native people's willingly adopted agriculture- it was usually forced upon them when the habitat that sustained them was destroyed... Just look at what is still happening in Brazil where ranchers and farmers are stealing the "extractive reserves" set aside for sustainable harvesting, and murdering the natives and activists...

CarbSane said...

Hi Mike: Nope I'm not a veganite, and I believe I generally equated us with omnivores in this post. I was challenging this notion that humans are optimized for non-starchy veggies when we clearly lack the apparatus to extract much energy from such food (which is why they are generally helpful for weight loss!) We have the apparatus to process plant foods - our teeth and jaw - but our digestive system points to those being starchy (and sugary) sources from which we're well equipped to extract energy.

I'm pretty far from being a vegan as I get probably 90% of my protein from animal sources, and perhaps 50% of that is red meat. I've been leaning more towards cutting the red meat some and I've certainly cut down on the hot dogs and sausages and such.

What's your personal opinion on poultry? I like chicken and turkey. I don't eat the skin except for the occasional half-order of chicken wings.

I eat mostly like your opinion, although I do eat a fair amount of rice in the mix as a starch source per Perfect Health Diet. The occasional grain is now part of my diet too - in the form of a low carb/high fiber wrap or bowl of steel cut oatmeal made with almond milk. I use tapioca starch in place of wheat flour in recipes where I "bread" things and dredge. I don't do baked goods.

I don't think we have any major disagreement here Mike. I don't think ANY evidence exists that VLC/VHF diets, as practiced (e.g. not comprised of cold-water mammals and fish), is optimal or even healthful in the long run at maintenance caloric levels.

CarbSane said...

@Charles, that's quite interesting. Bummer if I don't ultimately process it well. Things that make you go hmmmmmmmm.

I need to find a source for sashimi grade salmon and tuna and make my own kelp-free sushi. Luv me my unagi (eel) too.

CarbSane said...

Great blog Melissa!

Diana said...

Regarding evolution, this just appeared in NY Times:

Regarding "food addiction," I doubt there's anything new about that. What is new is constant surfeit, and lack of food shortages. Hence overweight and obesity.

CarbSane said...

You're right Diana. Coming from ED myself, there's nothing new about binging (aka overeating) and purging in history. It has been reported amongst the affluent for thousands of years. Only now, the poor are food-affluent.

My husband works in a very VERY poor neighborhood and most of his employees come from the immediate area. Obesity is also rampant. We didn't evolve to live on McD's and generic twinkies.

Nigel Kinbrum said...

Margaret said...
...The body clearly has pathways set up to utilize glucose, whereas fructose has to be metabolized only in the liver just like toxins or drugs...
That's not correct. Fructose can be metabolised by other parts of the body, but the problem with IV fructose is that because fructose "barges its way in" to skeletal muscle, also testis, kidney, fat tissue and brain via Glu-T5, it can result in lactoacidosis.

The reason why virtually all dietary fructose is mopped-up by the liver is that the liver gets first dibs at it via the portal vein and it's phosphorylated by fructokinase, which has a very high affinity for fructose (Km = 0.5mM).

Sanjeev said...
This comment has been removed by the author.
Sanjeev said...
This comment has been removed by the author.
Sanjeev said...

Margaret said...
...The body clearly has pathways set up to utilize glucose, whereas fructose has to be metabolized only in the liver just like toxins or drugs.
IIRC water-insoluble chemicals (which may be toxins and drugs) are handled largely by the mixed function oxidase system, which is highly non-specific

fructose is handled by highly specific systems that appear to have evolved specifically to handle fructose. I provisionally accepted "teh paleos" way back when, but this was one of the reasons I kept a large grain of salt handy[0] - most of them didn't know, or preferred to ignore,l that the human body did evolve systems specifically to deal with fructose, or very similar 5-carbon-ringed sugars.

[0] should have done the same with Taubes ... oh well, live & learn

(2 deletions above: I fixed an one error in the original, but in doing the fix, lost link to mixed function oxidase)

Margaret said...

Nigel and Sanjeev, thanks - I stand corrected. I did sit through that entire Lustig lecture on fructose recently so I'm just channeling him. Having been convinced by the VLC community that fructose was bad, I have since reconsidered and added fruit back in to my regular diet - seems logical that fruit is good for us, so why wouldn't we have ways of utilizing fructose? Makes sense.

Alan said...

@ Malcom Klein

I no longer believe that my ancestors camoe out of Africa.

MikeEnRegalia said...


Thanks for confirming that you're not a "veganite" - I guess your post could be interpreted either way depending on which part you focus on, and the feline teeth comparison happens to be a classic vegan stunt. Nothing wrong with it (after all, we're definitely not felines) in the context of your post, but like I said, it can be used to mislead.

About poultry: I love it, especially duck. I don't mind the skin either ... I generally don't mind fatty meat, I also love pork chops and bacon. The point which we need to focus on (and which you're also addressing in your HAES series) is that we shouldn't try to make our meals as fatty as possible - not only choosing the fattiest cuts of meat, but also adding additional fat. If you look at this from an evolutionary angle, it's obvious to me that humans did not have access to that amount of fat ... maybe occasionally, when they had killed a big animal and ate its organs, but for the most part, in Africa, fat is not plentiful. I know, the Inuit thrive on a high fat diet - but a) I doubt that they eat that way voluntarily and b) I'm sure they spend a lot of energy hunting their food and surely aren't overeating.

The later is especially interesting: Whether any given macronutrient composition is healthy obviously also depends on whether there's a caloric surplus or not. In the case of the modern low-carber who binges on low-carb junkfood and does lead a rather sedentary life (remember, Gary says that exercise only makes you hungrier) we can assume a caloric surplus, and in that case I think it should be obviously clear to anyone that fat, even if it was our prefered source of energy, isn't healthy.

Nigel Kinbrum said...

RE "Gary says that exercise only makes you hungrier".

If you go for a walk when you're slightly hungry, the walk will make you hungrier (via AMPk). So, don't go for a walk when you're slightly hungry! Have something to eat first. Low-intensity exercise doesn't cause cramps when you eat beforehand.

Try a 10 second sprint (if you're physically able). The massive "glow" after high-intensity exercise suppresses appetite rather than stimulates it. Ditto after lifting very heavy weights.

N.B. Don't over-exercise on a long-term VLC diet, as fully glycogen-depleted muscles can rapidly suck glucose from your blood and make you light-headed or faint (and then feel starving hungry later).

CarbSane said...

@Mike: There is something else about carnivores too, that they have hinged jaws that don't move side to side. While we don't chew like cows and horses, we have that mobility in our jaws. I know this is a vegan "stunt", but that doesn't mean it doesn't hold true.

I love duck! Obviously not an evolutionary food, but Turducken is an awesome treat :-)

Good thoughts on the fats. As I added in the comments of the Part V/HAES series, the high fat I believe is a culprit. Even most of the higher fat paleos do not engage in this sort of thing and end up in the 60% range of lower calories and higher protein. There's a huge difference, IMO between that and 75-80% fat that many are now promoting as optimal. I did a blog post on the fatty acid contents of seal vs. beef - it's on the FA content label or the paleo label here. Night and day. NO paleo I know comes anywhere near the FA profile the Inuit consumed. Therefore I consider all Inuit references largely irrelevant in my world :D

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