Ketogenic Diet Myths You Have Always Believed Were True Debunked

If you’re much of a fitness aficionado, chances are you know a myth or two about ketogenic diets. Check out this comprehensive article that debunks common ketogenic diet myths that you probably believe are true.

People often throw out arbitrary percentages to describe how crucial exercise and diet are for improving body composition. The short answer is that both are important for losing fat and being healthy.

However, if you could only do one or the other for the rest of your life, eating a healthy diet would probably be the best route as you simply can’t “out-exercise” a poor diet. Food is ultimately medicine for the body, and if you constantly feed your body with excessive calories than exercising won’t remedy anything.

Think about this physiologically, adipose tissue is liberated and oxidized under the proper circumstances (when a caloric deficit is achieved), not converted to muscle tissue. Do all the crunches and leg raises you want; if your body fat levels remain too high you won’t see anything but a pudgy belly protruding outward. Look at a really skinny, lean person who rarely lifts weights or even exercises…notice how you can still see their six-pack? It’s because they have such low body fat from either proper dieting and/or having a high metabolic rate (which still achieves the same endpoint of having more calorie burn than calorie consumption).

While “everything in moderation” has many applications to life, it doesn’t necessarily mean you can eat a moderate amount of sugar every day and still be healthy. This is largely because the word “moderation” is inherently vague (and contextual), and some people may view moderation as being three Whoppers a day from Burger King, whereas another person may view moderation as eating half a serving of ice cream.

Even a can of soda or two per day could lead to chronic insulin resistance and increase the risk of type-2 diabetes (which drastically increases the risk of obesity).

The main thing to consider is that certain foods/liquids are not good options if you want to be healthy (e.g. candy, starchy bread, fruit juices, soda, etc.). This is why keto diets are so great for health and longevity, because they limit processed sugar intake and keep your insulin, and thus blood sugar levels, in check.

This myth seems to stem from the fact that carbohydrates promote water retention in the body via glycogen storage. While that is indeed true, the weight loss from low glycogen stores is very short-term and only accounts for a few pounds at its peak.

When we break it down physiologically, the body stores carbohydrates as glycogen in the liver, fat, and muscle tissues. In fact, people often note how they feel/look “flat” when they don’t eat a lot of carbohydrates because their muscle glycogen (and thus, muscle volume) decreases accordingly. Each gram of glycogen attracts roughly 3 to 4 grams of water to store with it, giving your muscles a more “full” look when muscle glycogen is maximized.[1]

Considering that the average 200-lb male has about 80lbs of muscle mass, and that muscle mass is roughly 1% glycogen at max, this comes to about 363g of total glycogen stored muscle tissue. Now if you multiply that number by 3.5 (for grams of water held by each gram of glycogen, on average), then you’re easily looking at an extra 2lbs to 3lbs of “water weight” held in muscle tissue throughout the body.

Add in the glycogen stored in the liver and fat tissue and it can quickly add up to over 10lbs of water weight associated with glycogen. So yes, initial weight loss when switching to a low-carb/keto diet may be largely attributed to water loss, but after that period there is no glycogen-associated water weight to lose anymore.

This can’t be further from the truth going by research in recent years. Ketogenic diets appear to be beneficial for health and longevity for a variety of reasons, including their anti-inflammatory, neuroprotective, and anticancer properties.

In fact, research suggests that even supplementation with exogenous ketones is an effective means of decreasing cancer risk.[2] The mechanism for this is that cancer cells can’t use ketones efficiently for growing and replicating. In turn, exogenous ketone supplementation can increase survival rates of rodents with cancer upwards of 70%.

Moreover, research continues to grow on the therapeutic effects of ketogenic diets for protecting against neurodegenerative maladies like Alzheimer’s disease. Researchers think that neuroprotection from ketone bodies inherent anti-inflammatory nature in the brain.[3]

Lastly, ketones have a critical role in fighting inflammation throughout the body by blocking specific proteins known as inflammasones.[4] As you can see, there are actually many upsides to a ketogenic diet for prolonging life span and being generally healthy,

Ketogenic diets are actually quite simple to follow once you get a basic feel for what foods to shop for and consume. In general, you want to look for foods that are dense with fats and/or proteins but not carbohydrates. Certain foods that contain mostly fibre as the carbohydrate content may be suitable, though.

To make your life a little bit easier, the list below categorizes the best keto-friendly foods, ranked top to bottom on their “ketogenic potential”; the more you stick to the food groups higher up the list, the easier it will be to get into ketosis.

  • Meat, Poultry, and Seafood
  • Nuts and Seeds
  • Fats and Oils
  • Eggs and Dairy
  • Fruits and Vegetables
  • Ketogenic Snacks
  • Ketogenic Drinks
  • Exogenous Ketone Supplements

Shopping for a ketogenic diet is amazingly easy after you become accustomed to the food choices because you can buy in bulk and don’t have to worry about looking for so many different variations of the same food. Moreover, most restaurants serve dishes that are keto friendly, or you can simply alter the order so that is low in carb content and high in fat and protein (e.g. ordering a steak with butter and vegetables without fries on the side).

Many people seem to misconstrue the message behind keto dieting and think that it means vegetables and fruits are off limits. There are plenty of reasons to consume a modest amount of low-sugar vegetables while on a keto diet, including leafy greens and cruciferous varieties (e.g. spinach, broccoli, collard greens, etc.).

These vegetables are loaded with micronutrients that are essential for proper health and longevity, and they’re extremely low in carbohydrate content, making them fine for a ketogenic regimen. Moreover, if you don’t consume many vegetables on a keto diet, you’re likely to reach a point of electrolytes being severely low due to loss of water and constant urination (which are typical in ketosis).[5]

Therefore, it would be wise to consider making chicken broth which contains a good amount of sodium and some potassium, both of which are crucial electrolytes. You could also supplement with electrolytes if you’re urinating frequently, but go by how you feel. Multi-vitamins can also be worthwhile, but they don’t tend to have the same bioavailability as micronutrients from food sources.

Ketone bodies are not inherently fat-burning molecules in the body; rather, they are a source of energy. This would be analogous to saying that having a large amount of cholesterol in the bloodstream is indicative of fat burning. However, there is some preliminary research that suggests rats eat less when they supplement with exogenous ketones, which has positive ramifications on weight loss.[6] But the main thing to note is that more is not always better.

Ketones are either used directly by tissues or converted to acetyl-CoA, which can then be fed into metabolic pathways in the body and used for energy production. Yet, ketone bodies are much less likely to be stored as fat than protein and carbohydrates; in that sense, ketogenic diets are a great way to cut body fat and minimize excess fat gain when trying to build muscle.

In the event you did consume an exorbitant amount of ketones from supplementation (exogenous ketones), the body – specifically the kidneys – would rapidly work to filter ketones out through urine rather than converting them to fat tissue.[7] Again, this is not to say that you can’t gain fat if you consume an abundance of exogenous ketones (or if your body reaches an excessive level of ketone production), but that they are less prone to be converted to fat than other macronutrients.

Feelings of lethargy and tiredness when switching from a carbohydrate-based diet to a keto diet are typically short-lived and go away after the body adapts to using fat and ketones for fuel.

MCTs include caproic, caprylic, and capric acid, and are found primarily in foods like butter and coconut. Caprylic acid’s hydrocarbon chain is eight carbons long, so it is often referred to as C8 or octanoic acid/octanoate.

Research has shown that caprylic acid ingestion increases ketone body production significantly.[8]Even a nominal dose of caprylic acid-rich MCT oil can increase ketone body production fivefold. Since ketones and fatty acids are the primary sources of energy when carbohydrate intake is low, MCTs can be a great way to combat feelings of lethargy and tiredness.

Moreover, long-chain saturated fatty acids, which are typically found in foods like beef and dairy, are superb sources of long-term energy reserves for the body once it has adapted to a keto diet. Just give your body a week or two to adapt when you make the initial switch to a keto diet and you’ll notice that you actually have more energy than on your previous carbohydrate-based diet.

Quite the contrary, ketogenic dieting can be a great way to boost athletic performance, especially if you use the right kinds of fatty acids for energy. Remember, medium-chain triglycerides (MCTs), which are abundant in coconut oil, are rapidly oxidized by the body for energy and ketone production, making them superb for use before athletic events/workouts.

Also, elevated ketone concentrations in the blood drive the brain to utilize ketone bodies for synthesis of phospholipids, which induce growth and myelination.[9] Normally, glucose is the brain’s preferred substrate, which is much less efficient. In turn, ketogenic diets can enhance cognition and alertness, which have benefits for athletic performance.

Ketones also improve oxygen utilization, particularly throughout the central nervous system (CNS).[10] This effect decreases the likelihood of oxygen reaching potentially toxic levels in the CNS, which in turn has a number of other positive ramifications for not only athletic performance, but also overall health.

Lastly, exogenous ketone supplementation has a promising outlook for enhancing athletic performance for a variety of reasons, but mainly because they can induce an acute state of ketosis regardless of glycogen content in the body.[11] Unfortunately, at this time there is little direct data examining the effects of ketone supplements on athletic performance; the hypothetical premise behind their use is sound nonetheless.

As mentioned in another myth we covered – Myth: You can eat anything you want, as long as it’s in moderation – sugar intake, especially added sugar, on a ketogenic diet needs to be very restricted (if any at all) for the best results. Physiologically speaking, if you consume a few grams of sugar every day from natural plant sources (e.g. fruits and vegetables) you should be okay.

Bear in mind that we’re talking maybe 3 to 4 grams at a given time, maybe once or twice a day. The reason you want to restrict sugar intake on a keto diet is because most simple sugars (glucose, sucrose, etc.) spike insulin levels even in low quantities. While insulin itself doesn’t appear to affect ketogenesis, it does block the effects of glucagon on stimulating ketogenesis.[12]

The reason small amounts of fruit and vegetable sugar are typically okay on a ketogenic diet is because they are usually fructose-based carbs. Fructose, unlike other simple sugars, doesn’t stimulate insulin production. With that being said, consumption of fruits and high-sugar vegetables should remain very limited on a keto diet as they still contain a large amount of carbs which can negatively impact ketosis.

Fibre intake generally dips when switching from a carbohydrate-based diet to a keto diet, but that doesn’t necessarily mean that you need to worry. Physiologically, gut microbes ferment dietary fibre – specifically soluble fibres – into short-chain fatty acids. In turn, dietary fibres may act as prebiotics that feed healthy gut microbes and promote proper gastrointestinal health.

While that is indeed important, keto diets rich in medium-chain triglycerides (MCTs) can mimic the effects of dietary fibre since they influence growth of healthy microbes in the gastrointestinal tract.[13] Moreover, it’s important to note that just because you’re on a keto diet you can still get a good amount of fibre in your diet without negatively impacting ketosis.

Dietary fibres, especially from vegetables, won’t negatively impact blood sugar or stimulate insulin secretion, and therefore won’t impede ketogenesis.  It is imperative to consume some dietary fibre as it helps stimulate the bowel, and obviously going number two is good for health and longevity. Furthermore, vegetables are rich in micronutrients that many keto diets lack, so it is wise to consume a modest amount of leafy greens every day on a keto regimen.

While eating a large amount of protein will indeed induce a degree of gluconeogenesis on a ketogenic diet, the amount of protein needed to negate the effects of ketosis is rather astronomical.

If you think about this pragmatically, gluconeogenesis typically occurs when both carbohydrate and energy provisions are greatly limited (which is not the case on a proper ketogenic diet). If you’re eating a nominal amount of fat along with protein, there isn’t much gluconeogenesis going on since ketone bodies are being produced for energetic purposes. Your body doesn’t necessarily want to break down protein for energy, especially if there are other sources of energy it can utilize more efficiently.

Moreover, you would likely suffer many other side effects from having such exorbitant protein intake (e.g. gut distress, lethargy, flatulence, bloating, loss of appetite, etc.) before you induced so much gluconeogenic activity that you left a state of ketosis. When all is considered, you could eat upwards of 2 to 2.5 grams of protein per pound of bodyweight – which is still quite a high amount of protein intake – on a ketogenic diet and not have anything to worry about in terms of staying in ketosis.

Chemically speaking, the major difference protein has from carbohydrates and fats is that it contains nitrogenous compounds called amino acids. Amino acids are the building blocks of proteins, and thus are crucial for synthesizing muscle tissue.

Therefore, it’s not surprising that fitness enthusiasts assume they must be on an IV drip of liquid protein, especially when on a ketogenic diet. We recommend sufficient protein, but this doesn’t mean that protein is impossible to over-consume.

Protein can indeed convert to fat, but the pathways to do so are inefficient biochemically so the significance of this conversion is trivial. The majority of protein that your body doesn’t use for muscle protein synthesis or other anabolic processes is subject to hepatic gluconeogenesis and subsequent storage in the form of glycogen.

However, high protein diets are not in and of themselves “dangerous”. Unless you have pre-existing renal impairments, your kidneys will work to filter out the excessive urea from protein digestion so it can be excreted via urine. You can see a physician and ask for a blood urea nitrogen (BUN) test if you want to make sure your kidneys are working properly on a high-protein diet.

A practical goal for the masses on a ketogenic diet is 1.25 g-1.5 g of protein per pound of body weight. The good thing about protein is that it’s typically highly-satiating, making it hard to consume excessive amounts.

KetoStix are quite unreliable for measuring actual nutritional ketosis as they measure levels of acetoacetate instead of beta-hydroxybutyrate (BHB). Thus, KetoStix can result in false positives and “trick” people into thinking they’re in ketosis when they’re not.

Moreover, the body may excrete very little acetoacetate in the urine when you’re actually in a keto-adapted state, as BHB is the dominant ketone body produced. This would lead to KetoStix suggesting you’re not in a state of ketosis despite having high blood BHB levels.

For a more accurate measurement of nutritional ketosis/blood BHB levels, you need to purchase a blood ketone monitor either online or from a local pharmacy. These devices work very similarly to blood glucose monitors and require a simple finger prick to determine how many ketones are in the blood.

If anything, having very dark KetoStix is a sign that you’re reaching a critical state of acetoacetate content in the body (ketoacidosis). KetoStix are relatively useless for measuring nutritional ketosis. In fact, KetoStix are designed specifically to help diabetics avoid ketoacidosis and not for laypeople to measure BHB levels in the blood.

As mentioned in Myth: Purple KetoStix always means I’m in ketosis, to get a more accurate measurement of nutritional ketosis/blood BHB levels, you need to purchase a blood ketone monitor either online or from a local pharmacy. These devices work very similarly to blood glucose monitors and require a simple finger prick to determine how many ketones are in the blood


[1] Sherman, W. M., Plyley, M. J., Sharp, R. L., Van Handel, P. J., McAllister, R. M., Fink, W. J., & Costill, D. L. (1982). Muscle glycogen storage and its relationship with water. International journal of sports medicine, 3(01), 22-24.

[2] Poff, A. M., Ari, C., Arnold, P., Seyfried, T. N., & D’Agostino, D. P. (2014). Ketone supplementation decreases tumor cell viability and prolongs survival of mice with metastatic cancer. International journal of cancer, 135(7), 1711-1720.

[3] Hertz, L., Chen, Y., & Waagepetersen, H. S. (2015). Effects of ketone bodies in Alzheimer’s disease in relation to neural hypometabolism, β‐amyloid toxicity, and astrocyte function. Journal of neurochemistry, 134(1), 7-20.

[4] Youm, Y. H., Nguyen, K. Y., Grant, R. W., Goldberg, E. L., Bodogai, M., Kim, D., … & Kang, S. (2015). The ketone metabolite [beta]-hydroxybutyrate blocks NLRP3 inflammasome-mediated inflammatory disease. Nature medicine, 21(3), 263-269.

[5] Furth, S. L., Casey, J. C., Pyzik, P. L., Neu, A. M., Docimo, S. G., Vining, E. P., … & Fivush, B. A. (2000). Risk factors for urolithiasis in children on the ketogenic diet. Pediatric nephrology, 15(1), 125-128.

[6] Clark, V. L., & Kruse, J. A. (1990). Clinical methods: the history, physical, and laboratory examinations. JAMA, 264(21), 2808-2809

[7] Shannon L. Kesl,corresponding author Angela M. Poff, Nathan P. Ward, Tina N. Fiorelli, Csilla Ari, Ashley J. Van Putten, Jacob W. Sherwood, Patrick Arnold, and Dominic P. D’Agostino (2016). Effects of exogenous ketone supplementation on blood ketone, glucose, triglyceride, and lipoprotein levels in Sprague–Dawley rats. Nutrition & Metabolism, 13(9).

[8] McGarry, J. D., & Foster, D. W. (1971). The Regulation of Ketogenesis from Octanoic Acid THE ROLE OF THE TRICARBOXYLIC ACID CYCLE AND FATTY ACID SYNTHESIS. Journal of Biological Chemistry, 246(4), 1149-1159.

[9] Maalouf, M., Rho, J. M., & Mattson, M. P. (2009). The neuroprotective properties of calorie restriction, the ketogenic diet, and ketone bodies. Brain research reviews, 59(2), 293-315.

[10] D’Agostino, D. P., Pilla, R., Held, H. E., Landon, C. S., Puchowicz, M., Brunengraber, H., … & Dean, J. B. (2013). Therapeutic ketosis with ketone ester delays central nervous system oxygen toxicity seizures in rats. American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 304(10), R829-R836.

[11] Fery, F., & BALASSE, E. O. (1988). Effect of exercise on the disposal of infused ketone bodies in humans. The Journal of Clinical Endocrinology & Metabolism, 67(2), 245-250.

[12] Miles, J. M., Haymond, M. W., Nissen, S. L., & Gerich, J. E. (1983). Effects of free fatty acid availability, glucagon excess, and insulin deficiency on ketone body production in postabsorptive man. Journal of Clinical Investigation, 71(6), 1554.

[13] Rial, S. A., Karelis, A. D., Bergeron, K. F., & Mounier, C. (2016). Gut microbiota and metabolic health: the potential beneficial effects of a medium chain triglyceride diet in obese individuals. Nutrients, 8(5), 281.


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