Reviewed by the BioHackers Lab Team | Last updated: May 25, 2020

In today’s interview I get to speak with carnivorous diet proponent, Amber O’Hearn.

We talk about the role of nutritional ketosis and micronutrients on brain health, development & long-term health.

Amber is very passionate about the benefits of a nutritional ketosis and the carnivorous diet on our overall health.

Not only is she a carnivore herself, but she has been researching ketogenic and evolutionary based diets for over 20 years.

We get a chance to talk about ketosis from an evolutionary perspective, and we break down all the essential micronutrients needed for a healthy brain.

Amber also explains how the bioavailability of these micronutrients is a crucial factor to consider.

If you know someone who is interested in learning more about:

  • What is the key role ketosis and micronutrients play in the development of a healthy brain in children
  • Is being in ketosis good for long-term maintenance of brain health in adults
  • How the recommended daily intake values of vitamins and minerals might be different for people on a keto or low carb diet

Then this interview is for them.

I enjoyed this interview with Amber as, once again, she shared some of her valuable knowledge.

She really got me thinking about the way our brains have evolved and why they thrive on ketones as well as why we need to rethink RDA’s given the vastly different types of diets people consume.

Special thanks to Amber for joining me on the show.

Enjoy the episode!

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Hear episode 70 directly on your favorite podcast app by clicking a link below:

Speaker Links

Amber O'Hearn
Amber O’Hearn: Data Scientist & All Meat Diet Advocate

Follow, or find out more about, Amber on these official links:

Show Notes with Timestamp Links

Find summarised highlights of what we talk about during the interview.

Use the clickable timestamp links to jump direct to those points in the audio file below:

[00:19] – This week, Amber O’Hearn, who was previously on the show talking about her journey and experience on the all meat diet (Listen to her carnivore diet success story here), is back to share more great information with us. Amber is a data scientist by profession and has been researching and experimenting ketogenic and evolution-based diets since 1997.

[01:15] – Amber explains how ketosis is unique in humans. Often we talk about ketosis in terms of starvation (or mimic-starvation) and its function in helping us cope when food isn’t there. While other animals need to be in caloric or protein deficit to stay ketogenic, humans are an exception. This brings up questions about the role of ketosis in humans.

[04:00] – When we are born and suckling we are in a state of ketosis; ketosis of suckling is, in fact, common to many mammals. When weaned other mammals stop being in ketosis and this is also true for humans who go on to a high carb diet. However, with carb restriction children are much quicker in transitioning to ketosis than adults. Another interesting fact is that evidence has shown that the placenta is full of ketones which the foetus uses during brain development.

[06:42] – The difference in transition time to ketosis might have something to do with relative size and energy needs of the adult vs children’s brain. Amber explains that the energy needs of the brain could be driving this demand for ketones.

[07:57] – The hunter-gatherer societies can be informative in showing us the variety of diets in which humans can thrive in but aren’t very useful in terms of evolutionary environments as there is a significant difference to our access to megafauna today. Amber considers all of the hunter-gatherer societies we currently have (post-agricultural age) as an example of different solutions to the crisis of extinction of megafauna.

[09:56] – Amber highlights another important difference with hunter-gatherer societies today is that they have access to fire. From evolutionary perspective needed ketones to grow as carbohydrates weren’t a very consistent source of energy; the only energy source we had consistently available was animal fat.

[12:43] – We discuss the ideal diet for helping kids’ brain grow and develop. These days we have the ability to meet our energy needs using carbohydrates if we want to. However, we still need to ensure we are meeting the micronutrient needs. There are 5 different classes of micronutrients which are critical in the long term, acute sense.

 1. Minerals: iron, iodine, selenium and zinc. Amber explains why meat is the only way to get the needs for these properly met and addresses the problem with spinach.

[16:30]2. Vitamins: D, A, and B12 are critical for brain growth. Liver and eggs are excellent forms of pure retinol while the plant form comes as a precursor to vitamin A and conversion rates vary from person to person.

[17:57]3. Essential fatty acids are also subject to the problem of conversion. DHA and arachidonic acid are immensely important for the brain, which is largely made up of these fatty acids. Interestingly, the ketogenic diet increases the blood availability of these nutrients. The last two essential micronutrients are 4. protein and 5. energy.

[20:08] – Are RDA’s always useful? Amber explains how RDA was developed in the context of the high carb/grain diet. This means that the results are highly influenced by the grains and legumes which are full of anti-nutrients and affect absorption of micronutrients. Another problem is that these studies were all done in animals. Amber explains how the high carb diet and the ketogenic diet are distinct metabolic states that would affect the RDA of certain nutrients and gives an interesting example of zinc and oysters.

BioHackers Lab Tip: Listen to our interview with Dr Zsofia Clemens for more on this topic.

[28:38] – Amber believes nutritional ketosis is something evolutionary people would have been in a lot of the time; at least seasonally during the winter. We have two states; the fed state (glucose metabolism state) and the fasting state. People argue both are important for the human body to be at optimal state.

[32:28] – For people following the ketogenic diet getting enough calories is an important part of the equation. While there are studies in animals showing improved longevity in chronic, mild caloric deficit, it can also result in compromised vitality and reproductive ability.

[33:55] – How do we make sure we are eating right on a carnivore diet? Amber explains how certain parts of the animal contain a higher concentration of certain nutrients than others: specifically, the organs, the brain and marrow e.g. the liver is an excellent source of vitamin A. There are differing opinions within the community with regards to the importance of including organ meats. It is true, however, that something about carnivore diet allows for better recycling of certain vitamins and minerals.

[37:30] – Are the nutrients needs similar for maintenance of good health of the brain in older adults, too? Adults can tolerate more micronutrient deficits and the brain has already developed so it is not as crucial, however it has been shown that a lack of certain nutrients, such as zinc and iodine, will still compromise brain function.

[38:37] – Sometimes as we get older it can be a struggle to eat more meat, even though we need it for protein as well as other micronutrients. Has dental health something to do with that? Amber suggests ground beef may helpful in these situations.

BioHackers Lab Tip: Listen to our interview with Prof Stuart Phillips to find out how much protein we should be eating.

[41:22] – Amber believes that instead of chasing nutrient density (a measure of the highest amount of nutrition with low calories) we should focus on foods that will have a better proportion of nutrients, protein, and energy in a serving. Dietary quality, where all your dietary needs are met, (including protein, energy and micronutrient needs) is a better measure of the quality of food. E.g. a plant, no matter how nutrient dense, is going to be low quality because it will not supply you with protein or energy. This is something all animal-based foods naturally have.

[44:55] – Some of today’s takeaways: 1. The bioavailability factor of nutrients means RDA may be different for someone on a low-carb/ketogenic/carnivore diet, which is why they don’t need additional supplementation. 2. From the evolutionary perspective, we developed to thrive on ketones bodies. That could be why keto/carnivore diet is better for a healthy brain.

[45:50] – To keep in touch and follow Amber find her on Twitter or one of her blogs: or She will also be speaking at the Low Carb Houston Conference this October and the first carnivore conference in Colorado in March 2019.