Did you know doctors spend 12.5 hours learning about nutrition during their seven years of study in Sweden?

Did you know dieticians and nutritionists are not rooted in evolutionary biology?

This might be a bad thing for society.

But, it’s a good thing for you.

With a little effort, you can know more about what a healthy diet is than your doctor, and maybe even most dieticians.

When I became a certified nutrition advisor I learnt much more than doctors do (when it comes to nutrition).

Yet, I did not learn a logical framework to understand what is healthy, and more importantly why it is healthy.

I have taught you about the evolutionary framework (it should be second nature by now).

• Animals that live in an environment they are not adapted to develop diseases.

• We prevent and solve the disease by mimicking the animals’ natural environment.

In the last post, we went one level deeper as you got introduced to how cells are at the centre of our physiology.

• Functional cells lead to a functional organism, you.

• A functional organism is a healthy organism.

The cells’ function depends on energy.

I have spent endless hours learning the intricate complexity of metabolism.

Despite this, over 90% of my dietary choices come down to the model we are going to talk about today.

And the best part is it’s so simple anyone can learn it.

You don’t need to be a biologist, nutritionist or doctor.

All you need is an interest in what makes your body tick.

Three years into researching diet I had finally gotten a grasp on what a healthy diet actually was.

The problem was that I had a hard time conveying this to other people.

My explanation was always too complex.

People are busy. People are uninterested. People want to get to the point.

The point of talking about diet is to determine what is healthy, is it not?

As soon as I figured something out I wanted to shout it out into the world.

But, no one listened.

I often forgot I was trained in science, had a keen interest in nutrition and had spent over 2000 hours consuming information on the topic.

What made sense to me did not make sense to others.

Then one day I figured out the zoo analogy as a way of explaining the evolutionary framework for health.

But, all it did was give a simple explanation for the logic behind the paleo diet.

I knew my explanation had to be rooted in evolution.

But, I also knew it somehow had to contain cellular physiology.

The step between the two always felt far.

Until finally, I found the link.

A beautiful, yet simple thing, to bridge the gap between the two.

Our digestive system.

This might seem odd but soon it will all make sense.

There is no wonder you are confused about what to eat.

Almost no one talking about diet is rooted in evolution.

Because of this, they do not understand our digestive system.

Then, it does not matter how well they understand cellular physiology.

If someone cannot explain why something is healthy, in a way that you can understand, they don’t understand why either.

After embracing this model I can now look at food in a context-dependent manner.

I put foods into three simple categories and eat according to my needs.

Foods that are not in these categories I tend to avoid.

I don’t overthink what I eat anymore.

Digestion – The Missing Link

Why this model is so beautiful, to me, is that our digestive system has evolved to digest certain types of food (obviously).

This means we don’t only need to look at our past to determine what we ate.

We can also look at how our digestive system is built, or rather what it is built for.

More importantly, we can compare it to other animals, in particular other primates.

The digestive system is all the components involved in the digestion of food.

It runs from mouth to anus.

We will narrow in on,

• the stomach

• the small intestine

• and the large intestine

There is a general rule when it comes to the stomach.

The more meat an animal eats the more acidic the stomach acid is.

The reason for this is to kill foodborne pathogens.

In primates the stomach of humans is unusual.

With a pH of around 1.5, we have the most acidic stomach acid of any primate.

It is even lower than pure carnivores such as lions.

Humans have the same acidity as scavengers (vultures).

This suggests humans evolved to consume a lot of meat (especially rotting meat).

Potentially from scavenging meat from the kill of other predators or capturing too much meat to eat at once, or a combination of the two.

The intestine is where the food is further digested and where the absorption takes place.

The human colon (part of the large intestine) is 77% smaller than in chimpanzees relative to body size.

The human small intestine is 64% longer than in chimpanzees relative to body size.

The function of the colon is to ferment undigestable plant tissue (fibre).

The shorter colon allows us to get less than 10% of calories from fibre fermentation.

This suggests raw plant tissue was not a big part of our ancestors’ diets.

The small intestine, on the other hand, is where sugars, proteins and fats are absorbed.

The longer small intestines suggest humans ate a diet high in protein, fats, and maybe sugars (fruits & honey).

The change in how our gut looks makes it seem as if we slowly adapted to enable more calories from animals and less from plants.

A Diet Consistent With Evolution, Digestion & Cellular Physiology

In the last post, you got a formal introduction to cellular physiology and how it relates to health.

You learnt that cellular function is dependent on energy production.

You also learnt that cellular function is what creates a functional organism, you.

And that a functional organism is a healthy organism.

The question now becomes – what should you eat to maximise cellular function?

For cells to function they need energy.

To create the energy they need,

• fuel (carbs & fats)

• micronutrients (vitamins & minerals)

But cells also need building blocks (protein) to create and maintain their complex structure.

Simply put, to create cellular function we need to eat:

• macronutrients (carbs, fats & protein)

• and micronutrients (vitamins & minerals)

1) Evolution

The evolutionary framework of health tells us that we should eat what our ancestors ate.

This framework can help us determine the optimal macronutrient ratio.

Hunter-gatherer populations across the world get 25-35% of their calories from protein.

The calories coming from fat and carbs vary from group to group (usually depending on location).

For macros, you should hit at least 25% of calories from protein.

And, it is up to you to determine what carb-to-fat ratio works best for you.

2) Digestion

Our digestive system seems to be designed for a diet high in meat.

Suggesting our protein and fat should come from animal sources.

This means mainly saturated fat (butter, coconut oil, tallow, etc).

But, what about carbs?

Because plants, unlike animals, can’t move, they create chemicals as a defence against predators.

In plants, we can categorise the parts of the plant from most to least defended.

1. The seeds (nuts, legumes, grains) are the most defended as they are the children of the plant.

2. The root, stem and leaves are less defended but still defended because the plant dies if too much of any of them get eaten.

3. The fruit is the least defended as the plant wants animals to eat their fruits.

These three categories are also in order of digestibility.

1. Fruits (easiest to digest)

2. Root, stem and leaves (in the middle)

3. Seeds – nuts, legumes, grains – (hardest to digest)

Because of our relatively short colon, it seems like we should:

• limit seeds

• eat moderate amounts of roots, stems and leaves

• and liberal amounts of fruit.

This is not to say we should avoid vegetables.

Yet, we should probably not overeat them.

We have now determined that:

• our carb-to-fat ratio can vary

• we should get at least 25% of calories from protein

• our protein and fats should (mainly) come from animal sources

• we should eat fruits liberally, vegetables in moderation and limit seeds

3) Cellular Physiology

By looking at how our cells work we can go one step further.

Again, our cells need macro- and micronutrients.

But we can’t just eat them. They need to get into the cell.

This is why we eat for digestibility.

But, we also need to eat for nutrient density.

According to an excellent study, these are the most nutrient-dense foods:

• Eggs

• Seafood

• Red meat

• Organ meats

• Milk products

• Dark leafy greens

Start looking at food in three categories to maximize energy production.

1. Fuel (carbs & fat)

2. Building blocks (protein)

3. Nutrients density (vitamins & minerals)

4) Implementation

Step 1 – Hit your protein target by using foods high in building blocks (protein).

• Eggs

• Seafood

• Red meat

• Milk products

Step 2 – Use some nutrients dense foods at every meal.

• Eggs

• Seafood

• Red meat

• Organ meats

• Dark leafy greens

Step 3 – Add fuel sources as needed.

• Fats (butter, coconut oil, olive oil)

• Carbs (white rice, fruit, honey, sugar)

We have now used three different concepts to narrow down what we should eat for maximal energy (at the cellular level).

Using them we come down to three main points.

1. Eating for digestability

2. Eating for nutrient density

3. Eating to maximize protein intake

Eating this way gives our cells the building blocks, the nutrients and the fuel they need.

Our cells then make enough energy to build structures which maintain function.

And again, functional cells lead to a functional organism.

A functional organism is a healthy organism.

So now do you understand my saying?

Do more of what your cells want and less of what you want.

It isn’t as complex as we make it out to be.

We think it is complex because people talking about diet usually have no clue about what they are saying.

They might have specific knowledge.

Specific knowledge applied to health broadly always leads to confusion.

Two half trues always leads to a full lie.

Even though you don’t know how many molecules of ATP are created from one molecule of glucose you now know more about a healthy diet than those who do.

So, after reading this do you think you understand what a healthy diet is more than your doctor?

And, more importantly, do you now have a way of answering the question of why?

Why is red meat healthy?

Remember the three main points, digestibility, nutrient density and protein.

Red meat is easy to digest, has high nutrient density, and is high in protein.

Could it be called a superfood?

When determining if a food is healthy or not, ask yourself:

Q1: Is the food consistent with evolution?

Q2: Is the food nutrient dense?

Q3: Is the food easy to digest?

Let’s answer the question for what we are recommended to have as the base of our diet, whole grains.

Q1: Whole grains are not consistent with evolution as we started eating grains very late in our evolution.

Q2: Whole grains are not nutrient-dense (and contain antinutrients that impair nutrient absorption).

Q3: Whole grains are seeds making them hard to digest.

Whole grains are not healthy.

Ground yourself in sound reasoning and test what you think would work on yourself. 

It is your responsibility to figure out how you become healthy. 

And it is in your best interest to do so. 

Until next time, do what makes your future self proud.