CO2 and nutrition

The different fuel types that are available for our body need to be converted into acetyl-Coa to enter into the citric acid cycle and are processed equally. But the processes to turn glucose and fatty acids (and ketones) into acetyl-Coa are different. One of these differences is that glucose produces carbon dioxide (CO2) while doing this and fatty acids utilize oxygen (O2).

I have a theory in mind that states tissue level oxygen is slightly lower when using glucose for fuel than when utilizing fatty acids for fuel. As a consequence it would make you more susceptible to diseases that are either caused by or contributed by lack of sufficient oxygen. Numerous chronic diseases such as COPD, CVD, cancer, Alzheimer’s, TBI all are affected one way or the other by insufficient oxygen.

It is hard to figure out what goes on at tissue level. Most measures are done in arterials but this is already the level at which the mechanism of O2/CO2 exchange is adapting. There are theoretical models of O2 perfusion taking into account perfusion, diffusion based on diameter, blood flow rate, arterial saturation etc.. but those are theoretical and as far as I’m aware do not take into account the exchange effects of CO2 and other effects that could be of influence such as glycated haemoglobin which holds on to oxygen more strongly.

Something that can give us a clue is the following paper that looked at the effect of diet on CO2. In short the result showed us: high carb versus low carb (25%~20%) changed the ratio expired air versus CO2 (down, meaning a lower expired volume per minute (Ve) of CO2 per volume expired gas (VCO2)) or oxygen O2 (up, meaning a higher oxygen uptake (VO2) per expired volume of gas).

“Influence of diet on CO2 production and ventilation in constant-load exercise.”, Hughson RL, Kowalchuk JM, 1981,

This would seem self-evident when you know that the Respiratory Quotient (RQ) changes based on the fuel that you use for metabolism. For glucose the RQ is 1 meaning equal part of oxygen inhaled for an equal part of CO2 exhaled. For fat this RQ is 0.7, protein is 0.8 and a mix of the fuels will be between those values. There are exceptions to this but that is out of scope for now.

As stated in the paper, previously they believed that as Ve goes up, VCO2 would go up in proportion because CO2 would be the driving factor. I’m not so much interested in the driving factors. I’m interested in the difference that the diet brings.

A carb-centric diet produces more CO2 and thereby causes a higher tissue saturation of CO2, the partial pressure of tissue CO2 would be higher and as a consequence of this, less oxygen becomes available.

This is contrary to how we know the adaptation to low oxygen works. When more CO2 is produced, our system adapts to increase the ability to take in oxygen. Where CO2 concentration is higher in the arterials, it will widen up so that more oxygen diffusion can take place. CO2 itself causes O2 to detach from the haemoglobin so with higher CO2 production more O2 is released to compensate.

So what could be wrong with this? It seems like our body adapts just fine. Well, my speculation on this is that indeed it is compensated but it is not designed to do this systemic wide and chronically.

This is really important to know because a lot of chronic diseases are connected with hypoxia. I’m sure there are well defined rules for a diagnosis of hypoxia but what I have in mind is a level of tissue oxygen that is slightly below sufficient. So when I use the term hypoxia here in this article, I mean the ‘slightly below sufficient’ level. The level that causes small areas of cells to experience insufficient oxygen enough so that it can stabilize HIF-1alpha. This is the factor where cells start to adapt agains low oxygen.

Back to the Ve/VCO2. The way I understand gas diffusion is that it will always try to spread out evenly across the given space. Based on this principle we are able to pump up our tires. Compress air in the pump and the air will diffuse into the tire so that the pressure is equal everywhere (in the pump and in the tire). You may now understand where I’m going at with Ve/VCO2. For a given volume of air expired, we see less CO2 coming out on a low carb diet. It is already well established in research that a carb diet produces more CO2 versus a low carb diet so we completely expect this. But I consider the effect on the Ve/VCO2 a strong piece of evidence that the tissue CO2 level is higher. The higher CO2 production leads to a higher pressure of CO2 in the tissue so that there is a stronger diffusion effect.

Now Ve/VCO2 shows us more CO2 has to go out on a high carb diet but we also see Ve/O2 is higher on a low carb diet so a high carb diet is not able to bring in as much O2. Whether that makes glucose a more efficient fuel or not because it uses less O2, I leave that for another discussion. The difference in these gasses is not just during exercise, it is also at rest.

Could it be that oxygen is better distributed across the whole body under fat metabolism versus under glucose metabolism? If I’m right then having a systemic 100% metabolism of glucose causes a greater delivery of oxygen too early leaving other areas downstream under more hypoxic conditions.

One of the variables on O2 diffusion is the diameter of the artery. What would be the consequence of a chronic CO2 production? Wouldn’t the artery dilate chronically? If that would be the case then O2 diffusion becomes chronically less effective as the diffusion distance lowers by the increasing diameter. The coronary artery is already sensitive to oxygen as shown in the reference below where they tried to model the oxygen concentration in different 3D models. The second paper shows us how the diameter influences the diffusion distance. It is looking at kidneys in mice and it is not full prove as you have to take the wall thickness into account but it is the quickest reference I could find. There are papers around that show pressure is lower with increasing diameter (think about your garden hose) and such increase would further lower the WSS talked about in the 3D model.

“Oxygen mass transfer in a model three-dimensional artery”, G Coppola, C Caro, 2008,

“Vascular geometry and oxygen diffusion in the vicinity of artery-vein pairs in the kidney”, Jennifer P. Ngo, Saptarshi Kar, Michelle M. Kett, Bruce S. Gardiner, James T. Pearson, David W. Smith, John Ludbrook, John F. Bertram, and Roger G. Evans, 2014,

Nitric Oxyde

To further strengthen my idea, it is not until very recent (2015) that there is a publication where they express the difference that doctors have experienced between blood oxygen levels and tissue oxygen levels. In other words, the 2 are not necessarily in line with each other.

The following articles discusses about research that showed how important nitric oxyde (NO) is to the tissue oxygenation. Without NO, the mice died of heart attacks and heart failure.

“Molecular and functional basis established for nitric oxide joining oxygen and carbon dioxide in respiratory cycle”. ScienceDaily. 10 April 2015.

Insulin does stimulate NO production in endothelial cells so it facilitates its own distribution. I’m referring to insulin here because it is generally increased more due to carbohydrate intake and thus you could conclude that eating carbohydrates actually promotes oxygen delivery due to the effect of insulin.

“Nitric Oxide Directly Promotes Vascular Endothelial Insulin Transport”, Hong Wang⇑, Aileen X. Wang, Kevin Aylor and Eugene J. Barrett, 2013,

When we look at hyperglycemia or elevated blood glucose levels as seen post-prandial after a high-carb meal then we find that it actually reduces eNOS production by as much as 67%.

“Hyperglycemia inhibits endothelial nitric oxide synthase activity by posttranslational modification at the Akt site”, Du XL1, Edelstein D, Dimmeler S, Ju Q, Sui C, Brownlee M, 2001,

We also find lower eNOS in obesity and insulin resistance, which raises blood glucose levels. Type 2 diabetics have an increased risk for atherosclerosis and Dr Joseph Kraft even goes as far to say that those with cardiovascular disease, not identified with diabetes are simply undiagnosed. This is telling to the effect high blood glucose has and how its inhibiting effect on eNOS is stronger than the eNOS stimulating effect of insulin.


Well, it is not a scientific publication and won’t be peer reviewed so this will remain just an idea until science moves on showing this is all rubbish or there may actually be some truth in it. I’m handing it over to you now to further investigate and make up your mind.

Previously I did already write about this on Reddit with the assumption that tissue oxygenation is slightly lower. It contains some more material to look into and help you on your own way to optimize your lifestyle.

Feel free to leave a comment and raise other publications that confirm or refute some of the stuff I have written. That way we can further progress on our knowledge 😉

Dietary protein and glucose

I am a fan of the ketogenic diet because of all its likely health benefits. Not all of them are proven or necesessarily obtained because of the ketones themselves but a lot of the mechanisms are known and research is really booming. Would it be booming if there is nothing interesting about them?

In any case, some people consider a carnivorous diet and if they are also knowledgeable about the ketogenic diet, they’ll consider it also a type of ketogenic diet. What triggered me to write this post is that, in order for a diet to be ketogenic, you have to be producing ketones. And this ketone production depends largely on 2 factors. 1) The availability of free fatty acids in the liver and 2) low glucose in the liver cells.

It’s the 2nd point that I was wondering about because a carnivorous diet may include too much protein to support ketones. But not just a carnivorous diet, any diet that is high enough in proteins so I’m not being picky on carnivores. So let’s have a look at what research shows us to understand if this is a concern or not when you value ketones.

According to Ben Bikman (, protein raises glucagon and that would lead to raised glucose. And that is exactly what he showed in the following slide from the video.

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As you can see on the right side, protein (alanine) does raise glucose but does nothing to insulin. You can also see how alanine triggers glucagon secretion. Glucagon drives gluconeogenesis.

One caveat though, this is done via infusion and we know incretins have a role to play thanks to dr Michael Eades ( At least in glucose absorption. It would be great to see if a similar effect takes place on protein. He did not address that in the presentation.

Post image

So incretins could be having an effect on protein ingestion and it would be great if we could also have a look at the combination of protein and fat together. The following publication looked at fat separately and protein separately. The protein was an egg and milk type of protein meal, still with some carbohydrate in it.

  1. oleic acid (0.88 g/kg body wt; water was ingested after the oil to reach the volume of 400 ml; Casa Oilio Sperlonga, Priverna, Italy);
  2. protein dissolved in water [Promax protein 85R (Global, Rødovre, Denmark); 2 g/kg body wt, consisting of milk and egg protein; 4.4% carbohydrate and 2% fat] or;
  3. pure water (400 ml) were ingested within 5 min

Test results:

Post image
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“Incretin and islet hormonal responses to fat and protein ingestion in healthy men.” ; ;

We see the protein meal brings up insulin and glucagon. The carbohydrates with that meal would equal about 7gr for a 80kg guy so we cannot conclude on the insulin nor on the glucose levels but we see that there is no glucagon lowering effect of any kind which is what we wanted to know. Instead we see a rise in glucagon for a prolonged time, contrary to the Bikman presentation which also showed increase in glucagon but much quicker subsiding glucagon levels. Could this be due to digestion spreading the absorption into the blood over time? Likely. I have seen other research that looked at levels and absorption rate whereby fat was causing a delay and lower levels.

Insulin goes up due to dietary intake of carbohydrates. When the body produces/releases glucose in the blood stream it can still raise insulin but only marginally.

We know that insulin opposes glucagon ( The following research shows us that, although still a bit artificially composed, the glucagon-stimulating effect of protein is strong enough to oppose insulin’s inhibiting effect on glucagon secretion when you ingest the protein rather than use an isolated amino acid via IV.

The meal was tested in 2 groups, normocholesterolemic and hypercholesterolemic.

components of a 800kcal mealsoycaseinprotein-free
protein20% (40gr)20% (40gr)0% (0gr)
corn syrup solids60% (120gr)60% (120gr)80% (140gr)
soy bean oil20% (17.7gr)20% (17.7gr)20% (17.7gr)

Test results:

Post image

“Effect of dietary protein on serum insulin and glucagon levels in hyper- and normocholesterolemic men.” ;

As you can see, glucagon went up for the protein-containing meals while for the protein-free it went down. Glucose went up in all cases. Interesting is that despite the higher glucose content in the protein-free meal, the insulin respons seems to be somewhat lower resulting with higher glucose. Looking only at the normocholesterolemic group, protein and carbs together result in a higher insulin secretion than carbs alone. This matches with the presentation from Bikman.

Glucagon and plasma glucose

It should be clear by now that protein ingestion with or without carbs raises your glucagon levels. OK so does glucagon raises glucose in the blood and does it raise gluconeogenesis? This is actually well established but let’s show it anyway.

This paper used a nasal spray for getting glucagon into the blood, probably to test it as a treatment for hypoglycemia. They found a dose response and measured both plasma glucagon and glucose. The liver may be releasing from its glycogen storage so it doesn’t tell us anything about gluconeogenesis.

Post image

“Effect of intranasal glucagon on blood glucose levels in healthy subjects and hypoglycaemic patients with insulin-dependent diabetes.” ; ;

So how about gluconeogenesis?

Let’s look at this 2018 paper looking at the effects of glucagon.

Glucagon opposes hepatic insulin action and enhances the rate of gluconeogenesis, increasing hepatic glucose output. In order to support gluconeogenesis, glucagon promotes skeletal muscle wasting to supply amino acids as gluconeogenic precursors. Glucagon promotes hepatic fatty acid oxidation to supply energy required to sustain gluconeogenesis.

Enhanced gluconeogenesis induced by glucagon explains the increased urea formation in the liver. The carbon skeletons of amino acids are used to produce glucose whereas the amino groups generate urea.

patients with total pancreatectomy show elevated plasma concentration of most amino acids due to reduced gluconeogenesis associated with glucagon deficiency [4], [43], [54], [56]

Importance of glucagon during starvation in normal humans

Starvation requires adaptive processes that affect glucose, fatty acid, and amino acid metabolism in order to supply endogenous fuel to cells. The rate of hepatic gluconeogenesis increases to provide endogenous glucose to peripheral tissues, such as the brain. The skeletal muscle releases amino acids (mainly alanine) that are used to generate glucose in the liver. The adipose tissue releases free fatty acids that are oxidized in the liver to provide the energy required for enhanced gluconeogenesis. Hepatic oxidation of free fatty acids also produces β-hydroxybutyrate and acetoacetate that are used as fuel by the skeletal muscle. Glucagon secretion is a major driving force to the metabolic adaptation to starvation. Plasma glucagon level increases after 24–48 h of fasting, inducing hepatic insulin resistance that prevents glucose from being stored. Glucagon also promotes gluconeogenesis and ketogenesis [49], [63], [64], [65].

Glucagon contributes to fasting and post-prandial hyperglycemia in patients with T1D and T2D by increasing gluconeogenesis and hepatic glucose output.

Glucagon enhances gluconeogenesis in healthy subjects and patients with diabetes thus increasing hepatic glucose output.


“Metabolic effects of glucagon in humans”

Insulin goes up in the presence of glucose. And since meat doesn’t raise insulin, the means that your steak does not change into chocolate cake. Gluconeogenesis is therefore a process that happens based on need, not because of the presence of excess protein. In other words, if eating excess protein produces excess glucose, then we would expect increases in insulin – which we do not.

So does insulin go up in the presence of glucose? Dietary glucose, yes but when glucose is produced and released from inside your body then the insulin response is much less, if not absent. This was also clearly shown by dr Michael Eades comparing IV with dietary intake at the beginning of this article.

Protein ingestion triggers glucagon release and glucagon raises gluconeogenesis so is this a process based upon need? No. We see the rise in glucose from Bikman’s presentation and when testing the meals. What need was there for extra plasma glucose?

So eating excess protein DOES produce excess glucose and we do not expect insulin to raise much.

Finally on ketones I have to leave the point open but my guess is that the excess glucose will inhibit ketone production for a while until the glucose is handled. How long that will take I don’t know. Glucagon also triggers the liver to secrete glucose so I’d expect not more than a few hours. It will also depend on how much insulin is activated. You won’t be eating pure protein so there will be at least some fat with it which triggers both insulin and glucagon slightly.

Glucagon also promotes gluconeogenesis and ketogenesis

Finally, keep in mind that this comes from within the context of starvation under which insulin is as low as it can get and gluconeogenesis uses plasma amino acids that are available. Not a 350gr steak. That will make a difference in the ability to promote ketogenesis.

The way to check if it would be interrupting your ketones is of course to measure your blood ketone production. An alternative way could be to measure your glucose. If you are at your baseline glucose then you have too much glucose to reach a decent level of ketones but you need to figure this out by measuring both simultaneously. To produce sufficient ketones (>0.5mmol), your glucose level should be lower than baseline.


I think it would be good to start my blogs with a disclaimer that I can refer to at all times.

Since most topics will result in an understanding of how things work and how we can influence that through our lifestyle, people will make decisions that most certainly can have an impact on their health. Good or bad!

You should know I’m not a doctor and any recommendations would come from the idea of what I would do under those circumstances. I do not know your full circumstances neither can I decide for you what you should do.

I do not have a medical education nor do I pretend to know everything so you can be sure I will miss out on things because the body is hugely complex. I’ll do my best to mitigate but inevitably … I will make mistakes.

So the key message is, I try and provide information but you still have to verify if what I’m saying fully makes sense, whether it applies to you or not or how you can make use of it.

That said, I’m always open for your input. If you do something with my information and it didn’t work out as expected, do let me know by leaving a message under the articles.

Thank you for understanding this and I hope you reach your goals.

What drives me…

“Read not to contradict and confute; nor to believe and take for granted; nor to find talk and discourse; but to weigh and consider.”

— Francis Bacon

I was living a healthy life according to the guidelines.  Sportive (cycling, running, snowboarding, hiking), whole grain food with lots of vegetables, not a lot of meat, daily fruit intake and certainly avoid the fat on meat.  My sportive activities were fueled with the regular energy bar and sports drink.  Ask any doctor and I would be doing the right things for about 90%.

Yet I became sick.  After my cycling activities or after longer walks I started to tremble and sweat severely.  It was getting worse and worse.  Doctor visits didn’t help and declared me healthy.  Something was wrong, you know your own body, so it drove me to investigate.  A crucial change came when I got hold of a glucose monitor.  This showed me I had hypoglycemic events.  That is all I needed to know to start asking questions.  Why did I have a drop in glucose?  What regulates glucose?  I had other pointers as well.. Why did I experience it almost consistently after cycling?  Why did I have it also on these long walks?  What causes the trembling and sweating? This is the point where the quote comes in handy. Don’t just believe the information what is out there. Go for quality, the actual source of the information, and puzzle it together from there. Make sure the pieces fit by looking at the overall system and validate from different angles –> Weigh and consider.

From there, gradually the medical knowledge unraveled itself in front of me.  It became sort of an addiction because it stimulates my analytical mind.

This keen interest prepared me for an even bigger challenge that started this year.  I was diagnosed with a rare form of Hodgkin lymphoma.  My interest already expanded from answering the hypoglycemic event towards cellular biology.  One of the ways you can learn to understand how things work is by looking at what happens when it fails to work properly.  This already introduced me to several subjects such as Alzheimer, diabetes, cardiovascular disease, cancer and so on.  As soon as I got my diagnosis, I knew what to look for, where to look for and how to treat myself. 

The treatment showed positive effects such as reduced activity and reduced volume on the last PET scan. This knowledge and the ability to cure oneself from these problems should be in public hands.  Because I was able to gain access to the information, I want to help others to understand what I find and what to adjust to achieve true health because the guidelines that I was following were not leading me to health, they are leading to disease.

Neither will they work for you.

Who am I

My name is Sven Braem. I’ve always had an interest in health, like most people you could say. Who doesn’t want to be healthy, right? Yet following the dietary guidelines, lots of vegetables, some fruit, low fat, primarily oils from plant origins I was slipping away from health so I turned my general health focus into a personal health focus. I needed to fix myself.

This is the point where my interest and knowledge went up exponentially and found a lot of unsettled and contrary ‘science’. Science in brackets because it are not always hard facts, there is sufficient ideology, negligence and outright manipulation to support a personal agenda and unfortunately it finds its way into the public.

I want to share with you my discoveries, to get this information out and, who knows, may help out others providing an alternative to fixing your own health which doesn’t improve despite following the guidelines. Knowing how things work, you can come up with ways to influence it to benefit your health.

Whatever I come across I try to look at it from 3 angles:

  • What is the mechanism, how does it work?
  • Is it supported or contradicted by RTC’s / epidemiology? A mechanism is fine but does it work out that way in real life?
  • Does it make sense in the light of our evolution? Why does it work that way?

I am by no means someone with a medical nor biochemical background. As an IT analyst however, it does help me to continuously raise the questions how and why. It works in a certain way and there is a reason for it. The reason is not always so straightforward and neither is the how because you may be looking at an effect that is perhaps, within the bigger picture, a negligible fact. But that is what makes the discovery interesting, fun and continuous.

I hope you will enjoy the discoveries together with me to learn new insights and progress our understanding of the machine that is our body. In the end, we can adjust our lifestyle to fit what is optimal for our body.

After all, we don’t put diesel in the fuel tank of an aircraft so why should we do the same to our body?

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