Carnivore diet

The Truth About Carbohydrates: Why They're Beneficial for Optimal Health

The Truth About Carbohydrates: Why They're Beneficial for Optimal Health

By Daniel Velez and Carnivore Aurelius

If someone wants to maximize their health, carbohydrates are a vital part of that equation. For a long time, I discounted their importance...I honestly looked at orange juice like it was a glass of crack at one point.

Well I just came out of the carbohydrate closet and boy does it feel good.

After learning more about health and redefining it, my opinion has changed. I am not here to give you confirmation bias. I am here to evaluate all of the facts, change my opinion and relentlessly search for the truth (I will explain this all in a future manifesto). In this article, Daniel and I wanted to update you all on why we think that carbohydrates are a vital part of an optimal diet.

Let’s define health, as this has major implications for how you structure your diet.

What is Health?

Health is not simply avoiding carbs, or vegetables. Nor is it necessarily “eating ancestrally”. Real health is resilience. It is about maximizing the energy flowing through your mitochondria. Which in turn means maximizing your vitality, beauty, and intelligence. This ensures that your mitochondria do not degrade into more primitive energy production mechanisms like yeast do (the same fermentative process that happens when you get cancer).

See what separates us as humans is turning oxidative + nutrients into ATP and using that vital life energy to reach higher forms of consciousness. But when oxidative phosphorylation malfunctions, our cells revert into a primitive fermentation process, called the warburg effect. I will get into this in another article, but just because this fermentation process uses a lot of glucose, doesn’t mean that glucose causes it.

Back to health...

Health, in our opinion, is what the ancients called chi. It is:

  • Great, stable energy
  • Restorative, deep sleep
  • Clear skin
  • Thick, luscious hair
  • Good libido
  • Optimized hormonal balance
  • Peaceful mood
  • Low stress
  • Lean muscle mass
  • Well-functioning gut

It is SO much more than having a 6-pack, and this is part of where we have gone wrong.

See, almost any diet can work for weight loss. And just because a diet helps you lose weight, doesn’t mean it is optimal for your health. Let me explain more….

A proper approach to health will keep you free of cancer, autoimmune diseases, gut problems, and reproductive problems, while helping you maintain excellent cognitive health.

Whereas aging and disease, on the other hand, is a state of decreasing mitochondrial energy production and increased susceptibility to toxins and stressors.

Our environment today is loaded with stressors, so “health” is more important than ever. Why? Because fending off stress requires energy. And as your energy declines, not only do you become more unhealthy, you also lose your resilience to stressors which accelerates degenerative processes even further.

Thus, if you are on a diet that makes you lose weight, but it subsequently decreases your mitochondrial energy production, it could actually be detrimental to your long term health.

The ultimate goal is to maximize a healthy metabolism — the sum of all the chemical reactions in your body. And if losing weight detracts from that, maybe it isn’t so healthy after all. Yes, losing weight with all else equal is a good thing. But I believe there are healthier and unhealthier ways to lose weight (and I’m sure you do too … e.g. Why is anorexia unhealthy?).

When cellular metabolism declines, aging accelerates, the hormonal system suffers, and a wide range of disease-states and common annoyances occur, such as stubborn body fat, weight gain, muscle wasting, insomnia, etc.

This new reframing of health can help you to figure out what diet is best for you.

Where Keto Goes Right

The keto diet has benefited a tremendous amount of people. But what we will argue in this post is that the benefits aren’t actually from the ketosis part of the keto diet. And despite being a tremendous boon for people that have been struggling with their weight, it’s far from optimal for your overall long-term health.

Instead, I believe that many of the benefits from going keto stem from these changes:

  • Eating more protein
  • Cutting out gut stressors
  • More nutritious red meat
  • Removing seed oils and lowering PUFA consumption
  • Increasing consumption of saturated animal fats
  • Eliminating junk food

In fact, even when it comes to weight loss, this meta analysis here says it’s not necessarily the low carb-intake that’s doing it on keto, but it’s the higher protein.

The question I was faced with is if you can still retain these benefits without some of the harmful effects of keto that I will describe below.

Where Does Keto Go Wrong?

Many people today believe that keto can do everything from making you live to 180 to improving your credit score and giving you x-ray vision.

While there are certainly a number of benefits of keto, I believe that you can get them without actually being in ketosis.

In this article I am to present what I believe is ideal. It is not necessarily that a keto diet is deadly, for instance, but I now believe that it is not optimal for long term health — i.e. you can probably still be okay on keto forever, but if you want to maximize your chi, it is not the best route to go down.

First things first, let’s actually define the keto diet and have a brief overview of it, because a lot of people bend the definition of it to fit their own purposes, leading to people using the same term for different protocols, which can be very misleading.

What is the Keto Diet?

The definition I’ll be using for “keto diet” is a high fat, moderate protein, and very low carbohydrate diet.

When you eat a diet with adequate carbs, your body only burns a small amount of ketones for fuel (yes, you can actually burn ketones when eating carbs).

But when you’re on the keto diet, the depletion of glucose stores within the body requires the body to switch primarily from a glucose metabolism to a ketone metabolism, a secondary energy source that enables your body to burn fat for fuel.

However, as we’ll see shortly, that is a drastic oversimplification of the mechanisms at play.

There are a few reasons why I now believe this isn’t optimal.

#1 CO2

So, now that we know what the ketogenic diet is, let’s talk about CO2 and oxygen production within the body. This is important, so stick with me here.

If we’re defining health as maximizing your metabolism, CO2 is a lot more than a mere byproduct.

Here’s what you need to know: You want your cells to produce more CO2 to increase oxygen use and energy production.

The Bohr effect, which was named after Christian Bohr in 1904, describes the inverse relationship between hemoglobin’s oxygen binding affinity to blood pH and CO2 production. The Bohr effect allows for enhanced unloading of oxygen in metabolically active peripheral tissues such as exercising skeletal muscles.

Increased skeletal muscle activity results in localized increases in the partial pressure of carbon dioxide (CO2), which in turn, reduces the local blood pH.

Now, because of the Bohr effect, this results in enhanced unloading of oxygen by hemoglobin passing through metabolically active tissues, and thus improves oxygen delivery.

Importantly, the Bohr effect enhances oxygen delivery proportionally to the metabolic activity of the tissue.

As the body’s metabolism is more efficient, carbon dioxide partial pressure increases, thus causing larger reductions in local pH, and in turn, allowing for greater oxygen unloading throughout the body.

This is especially true in exercising skeletal muscles, which also may release lactic acid that further reduces local blood pH and, therefore contribute to the enhancement of the Bohr effect.

Another effect, called the Haldane effect, describes how oxygenation of blood in the lungs displaces carbon dioxide from hemoglobin, which increases the removal of carbon dioxide.

Consequently, oxygenated blood has a reduced affinity for carbon dioxide.

Taken together, we see that these relationships can cause a positive feedback loop, increasing oxygen use and improving metabolic function.

The opposite is also true as a negative feedback loop.

When this system is neglected or abused, the body’s cells cannot release adequate oxygen due to a lack of CO2, therefore energy metabolism subsequently decreases.

So, why does this matter in relation to our understanding of the ketogenic diet?

Burning glucose produces more CO2 than burning ketones. Let’s highlight some important things: Carbohydrate breaks down to pyruvate through glycolysis, pyruvate breaks down into the necessary CO2 (remember the Bohr effect) and electrons via the Krebs cycle, and lastly, that potential energy of electrons produces cellular energy via the electron transport chain.

As I mentioned earlier, when CO2 production is optimized, cells are not just able to increase oxygen use, which leads to a healthier metabolism, they are also reinforced by a positive feedback loop.

On the cellular level, a glucose metabolism leads directly to metabolic harmony. And, furthermore, this metabolic harmony is expressed on the hormonal level via optimal androgen levels and thyroid-function.

Carbohydrate oxidation consumes 50% less water and generates 50% more carbon dioxide than the oxidation of fat.

The reason for that, as shown in the image above, is that there is an extra step in glycolysis and using sugar through the decarboxylation of pyruvate, and that yields one extra molecule of CO2.

There is no analogous step in the beta-oxidation of fatty acids.

Furthermore, many people know the importance of the fat-soluble vitamins, but do not know that adequate CO2 production from a glucose metabolism ensures that the fat-soluble vitamins do their job efficiently and effectively.

"In the group, significant reductions were observed for both carbon dioxide output and PETCO2. Conclusion: The may significantly decrease carbon dioxide body stores."

(Rubini, Alessandro et al. “Effects of Twenty Days of the Ketogenic Diet on Metabolic and Respiratory Parameters in Healthy Subjects.” Lung vol. 193,6 (2015): 939-45. doi:10.1007/s00408-015-9806-7)

A study by Brundin, et al. (1993) compared the effects of glucose and fructose in healthy people and showed that fructose consumption significantly increased blood carbon dioxide levels.

The greater the supply of carbon dioxide, the better vitamin K can do its job

Carbohydrates are rich in carbon and oxygen, and when we break them down for energy we release these elements in our breath as carbon dioxide.

Vitamin K2 activates proteins by adding carbon dioxide to them.

We can increase carbon dioxide production by consuming carbohydrates, exercising, and maintaining robust thyroid status.”

Fatty-acid metabolism, on the other hand, occurs via beta-oxidation, a slow process that produces much less CO2.

As a result, less oxygen is available to the cell, slowing metabolic function in a negative feedback loop.

This downward spiral is intended as a survival response, sparing glucose for as long as possible, and in the process, creating an increasingly poor ability for the body to utilize glucose properly. (Kinzig, Kimberly P et al. “Insulin sensitivity and glucose tolerance are altered by maintenance on a ketogenic diet.” Endocrinology vol. 151,7 (2010): 3105-14. doi:10.1210/en.2010-0175)

(Kosinski, Christophe, and François R Jornayvaz. “Effects of Ketogenic Diets on Cardiovascular Risk Factors: Evidence from Animal and Human Studies.” Nutrients vol. 9,5 517. 19 May. 2017, doi:10.3390/nu9050517)

#2 Hormone Optimization

I now believe that glucose is critical for hormone optimization. Many people on keto have adequate androgen levels...yes. But over time, this tends to change. At least it did for me.

The science is clear: Your cells need glucose to carry out their functionality. Yes, you can produce glucose on keto via gluconeogenesis, but there is only so much that it can supply (and I believe it can be stressful, which I’ll describe below).

If there is a fixed amount of glucose from gluconeogenesis, that means it must be deprioritizing glucose for something else.

Leydig cells cannot produce testosterone in the absence of glucose.

Additionally, low thyroid impairs the conversion of cholesterol to androgens.

Both of these are affected by a keto diet.

“These observations thus suggest that reduced availability of glucose may be responsible for decreased testosterone synthesis or hypoandrogenism in the testis...

This study thus further supports the earlier finding that Leydig cells cannot produce testosterone in the absence of glucose (Rommerts et al., ’73; Amrolia et al., ’88).”

(Banerjee, Arnab & Mukherjee, Kaustav & Krishna, Amitabh. (2012). Age Dependent Variation in the Testicular Levels of Glucose Transporters (GLUTs) 4 and 8 and Their Correlation with Steroidogenesis in Mice...Biology of Reproduction. 87. 534-534. 10.1093/biolreprod/87.s1.534.)

#3 Randle Cycle

The Randle cycle, otherwise known as the glucose fatty-acid cycle, is characterized by a competition between glucose and fatty acids for their oxidation and uptake in muscle and adipose tissue (fat tissue).

The Randle cycle controls fuel selection and adapts the substrate supply and demand in normal tissues.

It is also a big reason why a lot of people avoid carbs. But I’m here to tell you why that’s wrong.

See, the thing about our bodies is that no matter how low you go with glucose intake, your cells still need to be able to burn glucose. You always have glucose coursing through your veins….

However, with excess lipolysis, glucose oxidation is halted.

The sugars in the blood cannot be utilized due to this fatty-acid metabolism shift, and because the cells’ ability to use glucose worsens due to the use of fatty acids, this ultimately results in insulin resistance and raises diabetes risk.

This is known as the Randle Effect.

And, shockingly, it can even help to explain the root cause of diabetes.

I believe that our understanding of diabetes is wrong. Blood sugar isn’t high necessarily because glucose ingestion is. It’s high because (1) your liver is pumping out excess glucose because it’s damaged (likely from high PUFA-intake and stress) and (2) you can’t properly metabolize the glucose in your bloodstream.

One reason why you can’t properly metabolize glucose is because of excess lipolysis via the Randle cycle — this shuts off glucose metabolism.

When you have diabetes, there’s typically excess lipolysis, which blocks glucose oxidation and contributes to insulin resistance.

Excess circulating fatty acids might also contribute to insulin resistance through the activation of Toll-like receptors (TLRs). Both TLR2 and TLR4 are required for FFA-induced insulin resistance in myotubes and in adipocytes <67–69>. It has been suggested that FFAs function through TLR4 on adipose cells and macrophages to induce inflammatory signalling and suppress insulin signalling <70>.”

(Guilherme, Adilson et al. “Adipocyte dysfunctions linking obesity to insulin resistance and type 2 diabetes.” Nature reviews. Molecular cell biology vol. 9,5 (2008): 367-77. doi:10.1038/nrm2391)

But when proper glucose oxidation is restored via increased carbohydrate-intake, diabetes is often improved or even reversed.

This paradox was shocking to me when I first learned about it --- eating more glucose can actually lower your blood sugar when you restore glucose metabolism.

(not to mention, glucose metabolism is also broken in a number of cases from nutrient deficiencies).

“…In 1935 Himsworth showed in normal men that isocaloric reduction of dietary carbohydrate actually impaired, and increased dietary carbohydrate improved oral glucose tolerance <1>. These observations of the effects of a higher carbohydrate diet on oral glucose tolerance in normal subjects have recently been confirmed <2-4>…Diabetic patients may also respond in a similar manner to high carbohydrate diets. Studies in which weight changes were not controlled showed that fasting blood glucose levels decreased <5,6>, glucose tolerance improved <5>, and insulin requirements were either unchanged or decreased <5-9>, when patients with insulin-dependent diabetes were fed carbohydrate-rich diets.”

“…To evaluate the effect of increased dietary carbohydrate in diabetes mellitus, glucose and immunoreactive insulin levels were measured in normal persons and subjects with mild diabetes maintained on basal (45 percent carbohydrate) and high carbohydrate (85 percent carbohydrate) diets. Fasting plasma glucose levels fell in all subjects and oral glucose tolerance (0 to 120-minute area) significantly improved after 10 days of high carbohydrate feeding. Fasting insulin levels also were lower on the high carbohydrate diet; however, insulin responses to oral glucose did not significantly change. These data suggest that the high carbohydrate diet increased the sensitivity of peripheral tissues to insulin.”

(Brunzell, J D et al. “Improved glucose tolerance with high carbohydrate feeding in mild diabetes.” The New England journal of medicine vol. 284,10 (1971): 521-4. doi:10.1056/NEJM197103112841004)

#4 Ketosis Raises Stress Hormones

In order to flip the survival switch from glucose to a fatty-acid metabolism, the body requires a shift in catecholamine response, and therefore, an increase in stress hormones, i.e. adrenaline and noradrenaline.

Instead of forcing cells to use fatty acids for a survival metabolism, this biochemistry would suggest that humans need to intake carbohydrates for a healthy metabolism and optimal hormonal balance.

During ketosis, stress hormones get elevated.

In regard to catecholamines, epinephrine increases during fasting, and this appears to be dependent on carbohydrate restriction <198>, implying that epinephrine is likely to be elevated during nutritional ketosis. Consistent with this, dietary carbohydrate restriction increases catecholamines at rest <155, 199> and in response to exercise <155, 199–202>. This may be, at least in part, a result of glycogen depletion <200, 203>, suggesting both direct and indirect effects of glycogen on AMPK activity.”

(Miller, Vincent J et al. “Nutritional Ketosis and Mitohormesis: Potential Implications for Mitochondrial Function and Human Health.” Journal of nutrition and metabolism vol. 2018 5157645. 11 Feb. 2018, doi:10.1155/2018/5157645)

It is, after all, a survival system designed to preserve your physical body, not a system that allows it to thrive. The Randle cycle prioritizes glucose for a good reason.

Many keto advocates never hesitate to point out that gluconeogenesis can refill liver glycogen…

However, this pathway is incredibly energy-demanding and inefficient, and is always taken under the direction of cortisol and other stress hormones, thereby supporting that it’s a survival mechanism, not a means for optimal health.

"Glucagon enhances gluconeogenesis from amino acids by (a) cooperating with glucocorticoid hormones in induction of enzymes that catalyze deamination."

— (Constance R. Martin, PhD, Endocrine Physiology)

There are studies that show therapeutic benefits of ketosis, but only in special cases during which the human body is already deep into a disease state.

They do not, in any way, show evidence for a chronic lifestyle-oriented ketogenic diet practice.

Listen, I once thought that ketosis was magical too. But after digging into the studies, there are usually many confounding factors that affect the results.

#5 Keto Slows the Thyroid...Whereas Glucose / Fructose Revs it Up

The previously mentioned shift in catecholamines also damages the thyroid gland. The thyroid is one of the most critical hormone-producing glands in the human body.

A malfunctioning thyroid can be an absolute nightmare for someone seeking better health and a faster metabolism.

In these two studies of subjects on keto, the researchers both found that keto lowered T3 over time:

Keto Causes Hypothyroidism:
Atkins (high-fat, low-carb) Diet Reduces T3:

Going back to our definition of health, the thyroid is the main captain for all energetic processes. It is one of the main determinants of health and one of the things the keto diet damages most acutely.

This is something I noticed on keto. The longer I stayed on it, the worse my thyroid functioned and the lower my T3 levels fell.

The thyroid’s hormones regulate vital bodily functions such as respiration, heart rate, muscle strength, body temperature, menstrual cycles in women, and the conversion of cholesterol to downstream steroid hormones and protective hormones.

Let’s go over how the thyroid gland works: The thyroid is part of the endocrine system which is made up of glands that produce, store, and release hormones into the bloodstream so that the hormones can reach cells within the body.

The thyroid gland uses iodine from the foods that you eat to make two main hormones: Triiodothyronine (T3) and Thyroxine (T4)

Hypothyroidism (an underactive thyroid), is very common in the present day, but its prevalence has been swept under the rug, so to speak.

Hypothyroidism is characterized by a slow metabolism, low body temperature, decreased rate of conversion from T4 to T3 (low levels of T3), and high cholesterol.

High cholesterol from keto is important to address, but I’m not going to write about it in the way that vegans do (saying that it leads to heart disease, etc.).

Instead, I now view it as a marker of stress and a state of hypometabolism, in which cholesterol isn’t being converted to crucial steroid and protective hormones such as testosterone, DHT, progesterone, pregnenolone, DHEA, etc.

In fact, high cholesterol is associated with low thyroid function and high levels of cortisol.

While on keto/carnivore, I had very high cholesterol.

But once I switched to a more pro-metabolic diet, my cholesterol fell and my androgen levels increased.

I'm not a fan of the demonization of cholesterol that occurs far too often.

However, I wanted to point out these facts.

This proven elevation of total cholesterol and reduction in the levels of serum T3 is ample evidence that the keto diet leads to a slower metabolism.

mimics a state of starvation changing the metabolism from an anabolic state that is insulin dominant to a catabolic state favoring a predominant glucagon state.

This switch affects the thyroid hormone status as its functioning correlates with body weight, lean mass, and dietary carbohydrate content…

, similar to fasting, significantly reduces the levels of serum T3 levels along with a concomitant increase in reverse T3, and these changes are correlated to the presence of ketone bodies.”

(Kuchkuntla AR, Shah M, Velapati S, et al. Ketogenic Diet: an Endocrinologist Perspective. Curr Nutr Rep. 2019;8(4):402-410. doi:10.1007/s13668-019-00297-x)

Moving on, let’s continue our overview of the thyroid gland’s hormones.

Both T3 and T4 are extremely important to have balanced.

But if you want to have a healthier metabolism, you especially want to increase the amount of T3 conversion that occurs inside your body.

So, where do carbohydrates fit into all of this?

The energy (glucose) that we get from carbohydrates is essential to fuel the production of thyroid hormones. Conversely, thyroid hormones are essential to maintain and regulate carbohydrate energy metabolism.

This is because parts of the brain ultimately responsible for thyroid hormone regulation, the hypothalamus and pituitary gland, require glucose to function.

In fact, the main regulation hormone, TSH (thyroid-stimulating hormone), is partly made up of glucose molecules.

In addition to these important roles, carbohydrate intake influences the amount of T4 that gets converted to T3.

When carbohydrate intake is reduced, the conversion of T4 to T3 declines.

This can be explained by the possible interactions between insulin and the enzymes that convert T4 into T3.

In several studies, results found that high carbohydrate diets have no negative impact on thyroid hormones, whereas very low carbohydrate diets do.

Low carbohydrate diets decrease T3 levels while increasing free T4 and reverse-T3 levels (high rT3 is a well-known sign of stress).

These studies below from Ray Peat all show that fructose / glucose significantly increased metabolic rate.

In another experiment, rats were fed either sucrose or Coca-Cola and Purina chow, and were allowed to eat as much as they wanted (Bukowiecki, et al, 1983). They consumed 50% more calories without gaining extra weight, relative to the standard diet. Ruzzin, et al. (2005) observed rats given a 10.5% or 35% sucrose solution, or water, and observed that the sucrose increased their energy consumption by about 15% without increasing weight gain. Macor, et al. (1990) found that glucose caused a smaller increase in metabolic rate in obese people than in normal weight people, but that fructose increased their metabolic rate as much as it did that of the normal weight people. Tappy, et al. (1993) saw a similar increase in heat production in obese people, relative to the effect of glucose. “

So, to sum it up nicely, the body relies upon glucose for the proper production of thyroid-signalling hormones and the conversion of T4 to T3.

#6 Other Benefits of Glucose / Fructose

I’m not saying to go out and guzzle sodas. I think that there are unique benefits to fructose in particular. For instance, in this one study, a sugar loaded drink caused inflammation, whereas the same amount of fructose did not.

“When people were given a 300 calorie drink containing glucose, or fructose, or orange juice, those receiving the glucose had a large increase in oxidative and inflammatory stress (reactive oxygen species, and NF-kappaB binding), and those changes were absent in those receiving the fructose or orange juice (Ghanim, et al., 2007)”

Lastly, there are some other benefits of adding glucose and fructose to your diet, especially on a diet with a substantial amount of meat. For brevity’s sake, I am just listing them below.

  • Eating protein on its own can cause hypoglycemia via the insulin response. Fructose can actually help with sugar balance.
  • Fructose helps to deplete phosphate, which is high in meat and on the keto / carnivore diets <*>
  • Fructose can increase GLP, which is impaired in diabetes
  • Sugar is very anti stress <*>
  • Honey is quite magical — in this study it reduced IgE (the immunoglobulin which promotes allergies), increased blood vitamin C concentrations and increased copper levels <*>
  • Fructose help to restore proper glucose metabolism: “When fructose is available, it can bypass this barrier to the use of glucose, and continue to provide pyruvic acid for continuing oxidative metabolism, and if the mitochondria themselves aren't providing sufficient energy, it can leave the cell as lactate, allowing continuing glycolytic energy production. In the brain, this can sustain life in an emergency” — Dr. Raymond Peat
  • Fructose accelerates the oxidation of ethanol (Thieden and Lundquist, 1967)
  • Fructose helps activate PDH which is usually deficient in cancer (Ishiguro, 1998)
  • Fructose can protect against endotoxin damage <*>
  • Fructose may help protect against lipid peroxidation from PUFAs <*>
  • Fructose may protect against prostate cancer by depleting phosphorous <*>
  • Fructose enhances mineral retention <*>


Life is about staying nimble and changing your opinions when new information arises. Boy, am I glad I did.

Feel free to reach out with any questions.

This post was written by Daniel Velez and Carnivore Aurelius. If you want more from Daniel, check out his awesome Twitter account here.

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