5 reasons grains are not a health food: part II
In part I of “5 reasons grains are not a health food” we began to look at why grains are a poor source of nutrition. Centred on how human digestive systems are not built for grains we look at a few more reasons why cutting back will be great for your health.
2. We have not evolved to eat grains
It makes sense for us to eat in a manner that suits our body, or as we have evolved to eat. Today, there is a lot of controversey around foods like red meat, which has been a staple of the human diet for mellenia. This seems ridiculous because this is one of the most complete, nutrient dense foods you can find and as omniverous animals humans have always eaten meat. Grains on the other hand have slid under the controversy rader and we eat them as a matter of course. Yet these are digestively challenging foods that our bodies haven’t really adapted to or evolved to eat.
Our ancestors have been around for about 6 million years and as hunter gatherers back then we ate predominantly wild meat and plants – and this fluctuated depending on what was available. Meat was our most calorie dense source of nutrition and provided essential minerals, vitamins and complete amino acids. In 1924, Raymond Dart discovered the first human fossil in Africa, which allowed him to develop a picture of these hunter gatherer’s diets that were incredibly meat centric (1).
Modern humans with genetics remarkably similar to us today have been around for about 200,000 years. Again, these ancestors of ours ate in a pretty similar way through this period. Meat, plants, the occasional bits of fruit when we got lucky or the season was right. Yes, we are much more intelligent and have less hair today, but like most of our body our digestive system is pretty much unchanged. There are a number of modern hunter gatherer populations that have been studied to provide a further understanding of how humans have historically eaten and how this impacts our health. Populations like the Inuit from the Arctic and the Tsimane people from Bolivia, eat diets that are predominantly meat and these communities have negligible rates of modern lifestyle ailments like cardiovascular disease and diabetes. In the Big Fat Surprise, Nina Teicholz, looks at studies of these populations in convincing detail. (2)
The agricultural revolution began 10,000 years ago, at which point humans started to incorporate some grains and diary in our diets. For people of Anglosaxon lineage, our ancestors have been eating grains for less than 200 generations. This is a mere speck on the length of time our bodies have had to develop the necessary functions to digest certain foods.
Fossils and skeletons of our pre-agricultural and post-agricultural ancestors show that when we started consuming farmed products, such as grains, we suddenly became less strong, capable and healthy animals. (3) The so-called Neolithic revolution around 8,000BC marked our transition from a hunter gatherer lifestyle to organised farming and trade. The world’s population grew rapidly as we were able to produce more food per acre by herding animals. This division of labour also allowed the organisation of society, as some humans were able to pursue leadership and innovation while others took care of their food production. We became more protected from the elements as we built shelter and made clothes. All of these factors contributed markedly to the improvement of our lives as human beings.
However, our transition to farming from hunter-gatherer lifestyles also coincides with an increase in dental cavities, bone malformation, nutrition and other disease. A trained medical anthropologist can quite easily tell the difference between a hunter-gatherer and a Neolithic skeleton because of dental cavities and bone malformations.
In his excellent synopsis of evolutionary nutrition, The Paleo Solution, Robb Wolf cites a specific example of the decline in human health. He looks at two populations from the same region:
1) “Hardin Village” – farmers who lived near the Ohio River valley 500 years ago; and
2) “Indian Knoll” – hunter-gatherers who lived in the same area 3000-5000 years ago.
Compared to the Indian Knoll, the Hardin Village people were shorter and less healthy. The farming population specifically showed signs of:
- More bone and dental cavities: average of 7 per person vs almost 0;
- Bone malformations;
- Shorter life expectancy;
- Various mineral deficiencies; and,
- Greater infant mortality.
Evolutionary biologist, Jared Diamond, describes the transition to farming as “the worst mistake in the history of the human race.” He cites fossils that show that European farmers were about 6 inches shorter than their hunter-gatherer ancestors and had a much shorter life expectancy. (4)
While hunter-gatherer diets obviously differed around the world depending on climate etc, there are a few common changes that occurred between the Palaeolithic and Neolithic ages:
We stopped eating as much wild meat and we started eating grains.
3. Human digestive systems are not built for grains
Humans are not ruminant animals, meaning we do not have four stomachs. Unlike herbivores such as cows, we do not have long colons to house the right bacteria to ferment plant fibres. (See illustration below). Because of this kind of digestive system cows and other herbivores must graze all the time. Humans should not eat in this manner because human digestive systems are not built for grains. We do not have the appropriate bacteria and digestive enzymes required to break down certain parts of grains and in fact other plants and legumes: human digestive systems are not built for grains. Historically, birds and vegetarian animals ate seeds and grains. We stuck to meat and vegetables. And we thrived as a species, developing the intelligence to be where we are today.
Humans have hydrochloric acid based stomachs that break down our food including meats. This is why I will never be a supporter of a vegetarian diet for health reasons, because humans are biologically wired to eat nutrient rich meat. Once the digestive process has been kickstarted by us chewing and then the production of stomach acid, food passes into our small intestine. The walls of our small intestine are slightly permeable, which allows us to absorb essential minerals and vitamins from out food as it passes through out gut. This is why protecting the integrity of our gut walls through a human appropriate diet is important. As you will read below, certain parts of grains are resistant to our digestive enzymes and can increase this intestinal permeability leading to immune responses and a range of health issues. Ultimately human digestive systems are not built for grains or diets like other herbivores.
4. Grains raise your blood sugar
We are regularly told by the nutrition “authorities” and “experts” that whole grains are a great low GI (glycaemic index) food, meaning they will give you a slow release of energy and leave you feeling satisfied for a while. Such advice also suggests that carbohydrates should constitute 40-65% of our daily calories. Grain based products are predominantly carbohydrate and carbohydrates react differently in the body to protein and fat. An excess of carbs can easily lead to weight gain, high blood sugar and eventually more serious conditions like Type 2 diabetes.
A quick look at carbohydrate in your body:
Everything that is not protein or fat is carbohydrate. That means potato. That means broccoli. And yes that certainly means grains. All carbohydrates are broken down in the body to form basic glucose molecules, a form of energy that can then be used by your brain and body. Glucose from any source behaves the same once it is broken down: it causes a spike in your blood sugar, which makes you feel energised for a while. When you eat a slice of white bread, you break it down into glucose and your body and blood sugar react just like you’ve eaten a sweet.
Once glucose is absorbed in the intestine, your liver ensures that your brain and red blood cells take what they need and then get to work storing the rest. Some of the excess is stored as glycogen in your liver and muscles. To enable storage of glucose your body needs insulin, which is produced by the pancreas. The more glucose you consume the more insulin your pancreas needs to produce.
When your muscles and liver cannot store any more glucose as glycogen, then the insulin allows it to be stored as fat. Ugh oh! The body has unlimited capacity to store glucose as fat. Triglycerides are fats that circulate in the blood and adipose tissue is body fat. For obvious reasons we want to limit the amount of both of these. This means not eating too much carbohydrate and instead getting calories from other macronutrients – fat and protein.
We will learn more about food, eating and hormones in a later article. The important thing to note is that while grains are promoted as a healthy wholesome food, once in your body they are treated much the same as a sweet or something sugary. Your bowl of cereal topped with fruit and low-fat yoghurt in the morning is actually not that different from a sugary snack!
This is a measurement used to gauge how your blood sugar rises over a period of 90 minutes after you eat something. Protein and fat only raise your blood sugar very slightly and so eggs, chicken, beef etc have a GI of 0.
All grain-containing products are predominantly carbohydrate and will inevitably raise your blood sugar. However, the concept of GI and the many foods that are promoted as ‘healthy’ because they are ‘low GI’ is misleading. Wholegrain bread and oats, which both have a low GI ratings, but still raise your blood sugar causing insulin production. Do not be fooled by something marketed as low GI, as Dr William Davis explains here. (5)
From this brief explanation of carbs in the body, you should see that we really don’t want to be consuming too many carbs, especially nutrient poor sources like grains (read more about this in part I of this article).
While our bodies do need some carbohydrates for glucose based energy, if absolutely necessary we can fulfill all of our energy needs with calories from fat and protein. While low-carb diets are defintely not appropriate for everyone, the fact your body can turn other macronutrients into carbohydrate means we can reject the notion that you “need” wholegrains in your diet. The amount of carbohydrates that we are advised to eat as part of a “healthy wholegrain rich diet”, is far in excess of the number of carbohydrates humans require. This can lead to chronically elevated blood sugar, which in turn leads to other health complications. Another reason that healthy wholegrains are just not the health food that they are portrayed to be.
5. Grains have their own defence mechanisms to stop them being eaten by animals
Now we have covered some of the less serious reasons not to eat grains, it’s time to get into where the real problem with grains lie.
All living things have ways to prevent them from being eaten. These mechanisms are pretty obvious when it comes to animals – you just need to see an episode of David Attenborough to see that a gazelle has fast legs and agility, whilst a tiger is extremely quick.
Grains are the seeds of plants, so the reproductive parts of these living organisms too. And the part we eat, which is the most nutrient dense, is also the reproductive centre of the grain. But grains can’t fight you off by running away. Nor do they have a poisonous coating to deter you. Just like other organisms grains need a way to protect themselves long enough to reproduce and this is why they are really rough on your digestive system.
In his book, Your Personal Paleo Code, Chris Kresser describes mechanisms that grains use to defend themselves include toxins that can:
- Damage the lining of the human gut;
- Reduce our ability to absorb essential nutrients including protein;
- Bind to essential minerals such as calcium, magnesium and iron and making them bio-unavailable (ie unusable) for your body.
Sounds a bit worryin doesn’t it! It’s too much detail for now, so in my next post on grains we will learn a bit more about the biology of grains to understand why they are problematic.