The Poor, Misunderstood Insulin – Evolutionary Benefits

The Poor, Misunderstood Insulin


Bill, thank you for inspiring me with the title.

The current paradigm of health does not seem to want to include a bigger picture, a broader view of what human optimal condition is. It’s kind of stupid that we’re mostly focusing on mitigating the effects of disease rather than shooting for the root causes. ¡Hala! functional medicine!

We are now living in a mismatched environment. Dan Lieberman and Jack Kruse are eye openers with regards to this. But what’s a mismatched environment?

The Mismatched Environment

It is an environment not compatible with human health and wellbeing. It does not promote it. To illustrate: eating several times a day everyday is a mismatched condition. We’ve not been doing this for most of the human history.

A mismatched environment is where diseases like T2D and obesity emerge. Examples of other mismatched conditions which degrade human health are:

– too much artificial light
– too much electricity, wireless technology, and EMF radiation (electro-magnetic field)
– too much heat for people living in colder environments
– inadequate footwear that prevent people from being grounded
too much food available everywhere 24/7
– and so on.

But What about Insulin?

I believe that everything that has to do with human health falls into place as long as it is perceived through an evolutionary perspective. That’s when everything starts making sense.

And insulin is not an exception. If we take a closer look at human evolution, we can say that for about 99.9% of our history insulin was a life saving factor.

Soeters and Soeters (2012) say that insulin resistance (or the ability to selectively modulate the cellular/tissue response to insulin) is evolutionarily well preserved in insects, worms, and vertebrates including humans.

Think about bears for example and their feeding cycles as the end of summer approaches. They become insulin resistant while consuming more than 20,000 kcals a day. They need to store as much bodyfat as possible as hibernation approaches. This mechanism helps them survive for several months without eating and drinking anything.

Humans do not hibernate but the action of insulin helped us survive over similar periods of famine throughout the millennia. Nowadays, we paint a totally different picture. We may see insulin as the culprit. But is it?

Soeters & Soeters (2012) also say that having been under so much evolutionary pressure, insulin’s persistence suggests that it benefits survival of the species. Why?

Hominid species have started eating higher-quality, energy and nutri-dense foods as Homo Erectus emerged some 1.9 mya (million years ago). I’m talking about animal foods here. We assume their eating patterns were not regular, so whenever they had a big hunt for dinner, they were probably overeating.

Hence, insulin allowed them to package excess energy from food into the adipose tissues through lipogenesis so that when times were scarce they would not die of starvation. Excess body fat allowed them to make it through harsh times of famine. This was a survival mechanism.

I’m overly simplifying things here for the sake of understanding them better.

The availability of lower quality foods such as tubers and fruits was probably higher but these foods barely provided energy for daily demands. See Lieberman’s arguments.

Too Much Food

As the earth cooled down and food became scarce, it was critical for insulin to do its job whenever food was available. It was a simple mechanism:

Over-consuming nutrients and filling the glycogen storage promoted higher insulin levels which led to fat accumulation through lipogenesis and other metabolic pathways.

Many aspects from the lives of early hominid species are not certain, but one thing may be for sure: food was not as available as it is today.

Now, people have higher insulin levels all the time due to the consumption of foods that promote this mechanism, such as over-consuming carbohydrates and, to a lesser extent, protein.

It’s a defective and misleading mechanism because it promotes false hunger. The body is not deprived of nutrients but whenever one consumes carbohydrate rich foods, insulin levels increase to reduce blood glucose levels and when blood glucose levels are low (some 2-3 hours after eating), hunger increases. It is a vicious cycle that many people feed to everyday.

Early humans probably felt hungry 2-3 hours after overeating, but they may not have been able to keep feeding the mechanism due to the lower availability of food. Hence, as hour passed since their last meal, hunger was beginning to be suppressed as fatty acid and ketone metabolism started replacing glucose metabolism.

As glycogen levels got depleted in a matter of hours to days since feeding, this survival mechanism kicked in.

George Cahill (2006), probably the best starvation researcher, says that were it not for the BOHB (beta-hydroxybutyrate and aceto-acetate providing brain fuel, we Homo Sapiens might not be here.

The Poor, Misunderstood Insulin - BOHB Levels

This mechanism would allow early humans to maintain higher energy levels and a clear mind so that they were able to hunt their next prey and repeat the entire eating and no-eating cycles all over again. Cahill (2006) says that even archaea use BOHB for energy storage, which suggests it has been around for well over 2-3 billion years.

It’s also interesting how body produces its necessary glucose from different substrates. According to Cahill (2006):

Hepatic glycogen contribution to blood glucose is essentially zero by the second or third day of starvation. Total splanchnic glucose production in several weeks’ starvation amounts to approximately 80 grams daily. About 10–11 grams/day come from glucose synthesis from ketone bodies, 35–40 grams from recycled lactate and pyruvate, 20 grams from fat-derived glycerol, and the remaining 15–20 grams from protein-derived amino acids, mainly alanine.

The Poor, Misunderstood Insulin - GNG Starvation

Yet, many physicians see elevated blood ketone levels as a toxic state. It may be a toxic whenever both blood glucose and ketone bodies are extremely high, such as in T1D for example.


I’d like to remind that for me everything makes much more sense when seen through an evolutionary perspective. And even though many of us live in mismatched conditions due to the current environment, it does not mean we cannot get closer to our adapted nature.

Going to sleep when the sun goes down, reducing artificial light, reducing EMF radiation, walking barefoot on the beach and on the ground, intermittently fasting, sleeping in cooler environments, as well as many other interventions would have a powerful mitigating effect on these mismatched conditions (diseases).

Adaptation takes time and we’re probably still evolving. But our bodies cannot keep up with the blazingly fast ever-changing environment. We should take it easier. Maybe in time we’re gonna be more able to support higher EMF radiation or higher food intake without getting into a diseased state. Who knows? Only time may tell.


1. Soeters, M. R., & Soeters, P. B. (2012). The evolutionary benefit of insulin resistance. Clinical Nutrition, 31(6), 1002-1007.

2. Fernández-Real, J. M., & Ricart, W. (1999). Insulin resistance and inflammation in an evolutionary perspective: the contribution of cytokine genotype/phenotype to thriftiness. Diabetologia, 42(11), 1367-1374.

3. Cahill Jr, G. F. (2006). Fuel metabolism in starvation. Annu. Rev. Nutr., 26, 1-22.

4. Daniel Lieberman – The story of the human body

5. Jack Kruse – Epi-Paleo R(x) – The Prescription for Disease Reversal and Optimal Health

6. Tattersall, I. (1998). Becoming human. New York: Haîcourt Brace.

7. Clinton Ober – Earthing: The Most Important Health Discovery Ever?

Photos: here and here

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