The following sections are draft parts of a book I’m writing. The goal of the book is basically to write a piece on food and nutrition that 20 year old me would have loved to have. Practical and to the point.
Evolution of the human body
The human body is the product of adaptation to its environment. Please remember that neanderthals first emerged 500,000 years ago, and anatomically modern humans 200,000 years ago. See Timeline of Human Evolution on WikiPedia.
Now imagine the surrounding our ancestors developed in generation after generation
The point here is that the human body evolved to deal with a number of very harsh conditions. For example:
- Food not being available every day
- Sweet foods (fruits) being rare outside a few summer months
- Different foods different times of year
This has resulted in an amazing biochemical machine that is capable of:
- Going without food for 3 weeks (yes, a healthy human can do that)
- Digest a wide array of plants and animals
It also has some downside from our modern perspective because we:
- Feel attracted to sweet things (used to be a rare treat)
- Are prone to eating more than we need (food used to just disappear)
But we adapted right?
Yes and no. Yes we adapt to our surroundings, otherwise you could argue we would all overeat and consume only sugar. FYI 39% of the world’s adults is overweight, of which 13% obese. See WHO data, updated June 2016.
Humans have the advantage that our brains and minds are relatively developed, meaning we can rationally override our base urges. That is why we are capable of handling our primal heritage.
We can retrain the brain very well, but our body far less
Evolution is about sex before dying
Evolution is about survival of the fittest. The ‘fittest’ is determined by the amount of offspring that survives. Survival of the one who passes along his/her genes most.
Those who have more kids pass along their genes.
Let’s say you and me are the only ones alive, and we can spontaneously reproduce ourselves. I make 20 copies of myself, you make one.
In the next generation most people have my genes
Those who can deal with their surroundings survive
We are animals that are food for a bigger animal. I have claws and you do not. I have 10 kids with claws, and you have 10 kids without claws.
The predator hunts us, my kids defend themselves, yours get eaten. The next generation again has more of my genes
Genes win if you reproduce a lot
We are humans. I have fast running genes so don’t get eaten by lions. You walk slow and have in incredible sex drive. By age 30 you die having had 15 kids, by age 70 I die having had one kid.
The next generation has more of your genes
So have we adapted to eating the things we do now over how our body machinery evolved?
- Does type II diabetes from chronic sugar overconsumption kill you before you have kids? No.
- Does cardiovascular disease from chronic unhealthy lifestyle kill you before having kids? No.
- Does a compromised immune system from malnutrition kill you before having kids? No.
In fact, most abuse you can throw at the human body does not kill you before you can reproduce. Upside: our bodies are absolutely amazing. Downside: our genes have not changed a lot over the generations to adapt to our food.
This part is a little bit scary in my opinion.
- Vitamin D deficiencies are common (80% Ecuador kids according to FACEB on vitamin D in Ecuadorian children, 87.1% of 45+ UK adults in winter according to this PubMed entry for Hypovitaminosis D in British adults at age 45)
- Loads of people get too little magnesium (68% of US adults consume below the RDA. See thisPubMed entry for Dietary magnesium and C-reactive protein levels)
- B12 deficiency is not uncommon, especially in elderly ( over 20% according to this CMAJ study on vitamin B12 deficiency in elderly patients or around 15% according to this AJP study on Vitamin B12 Deficiency and Depression in Physically Disabled Older Women)
We currently do not have good nationwide data on vitamin blood levels as they are not screened regularly. But everytime I read a study, the numbers frighten me.
Basically most people are likely to be deficient in something
Question to you: have you ever tested yourself for vitamin D? It’s cheap or even free in most countries.
Recommended daily amounts
The goal of recommended amounts is simply to keep you from falling ill. Please note that it is not to keep you in optimum health.
Insufficient vitamin C will give you scurvy, as happened in the days where ships took months to sail to destinations.
Is the function of vitamin C to prevent scurvy?
I would argue not. In fact it is essential in the immune system, skin flexibility.
Most RDA systems stem from old data and old science. Take the US, where the requirements were set around 1968 see WikiPedia on RDA.
I am not saying these guidelines are useless, but I do think they paint an incomplete picture.
You are what you eat
This saying it quite literal. Your body builds itself from the things that you ingest. And it makes total sense.
If you ingest collagen, it makes sense your that body will use it to build the extracellular matrix that makes your skin flexible. Which seems to indeed be the case. See this Springer article: A new view concerning the effects of collagen hydrolysate intake on skin properties.
The human system in incredibly complex and science does not fully understand what all foods do to the body. But the principle is simple:
Eating bad food gives your body bad building blocks and vica versa.
If you want a well functioning body, give it the right materials. You wouldn’t expect a diesel car to do well on regular gasoline/benzine either.
The problem of mass production
What happens when the market demands cheap foods?
“ … the dominant effort is for higher yields. Emerging evidence suggests that when you select for yield, crops grow bigger and faster, but they don’t necessarily have the ability to make or uptake nutrients at the same, faster rate.” See University of Texas: Study suggests nutrient decline in garden crops over past 50 years
Industrialism gave us cheap food, but also lower quality.
The nutrients in plants come from the soil and their metabolism of it, which takes time. Most consumers want cheap food, which is grown fast, harvested early and exhausts soil as much as possible. It’s simple economics.
A comparison of the mineral content of 20 fruits and 20 vegetables grown in the 1930s and the 1980s … significant reductions in the levels of Ca, Mg, Cu and Na in vegetables and Mg, Fe, Cu and K in fruit … water content increased significantly and dry matter decreased significantly in fruit … a nutritional problem associated with the quality of food has developed over those 50 years. See British Food Journal Historical changes in the mineral content of fruits and vegetables
The nutrients in animals come from their food and their metabolism of it. Most meat comes from animals fed cheap foods (corn, soy) as opposed to what they naturally eat (grass). That impacts the nutrients in the meat. Grass fed beef has more omega 3 fatty acids. See A review of fatty acid profiles and antioxidant content in grass-fed and grain-fed beef for example.
This is no tinfoilhat conspiracy. It’s science and plain reason.