Popsci recently featured an article titled, “Sorry, keto fans, you’re probably not in ketosis.”  While I am a fan of PopSci, I am also well studied on the ketogenic diet as well as many other diets (This is a result of the importance of nutrition in body composition and performance as a strength and conditioning specialists as well as personal trainer).  This particular article was filled with a large amount of misinformation and logical fallacies that I thought should be addressed.  Below I have quoted the original article and provided my commentary and citations.

Bonus:  Here is a handy guide for spotting bad science (link to original url).

See the full original article here.

*The article has been updated and attempted to correct many of the flaws in my critique.  The critique below is off the original article that I had read, but many of the same points stand in the corrected article.  The misconceptions on protein are the notable remaining issues while they removed almost all information on fiber content of the diet.

“Keto is hard. If it’s not hard, you’re probably not doing it right.”

[This may be a fair statement as keto can be hard for people, but so are most diets.]

“the ketogenic diet (also called keto) was never supposed to be fun. It was supposed to treat severe epilepsy. And as a medical treatment, it was only intended to be administered under the supervision of trained nutritionists and physicians.”

[It was used and named after being used as a treatment for epilepsy, but diets on the keto spectrum existed well before this “re-discovery” and have been used in the medical field for other reasons since.  Its initial medical purpose does not exclude the possibility of benefits in other areas of health. Banting wrote one of the earliest works on weight loss and describes a diet that was very likely ketogenic (Banting, W., 1864), Yudkin used very low carb diets in his practice around the same time Ancel Keys was performing his starvation study (Guetzkow, H. S., & Bowman, P. H., 1946) which resulted in similar weight loss results without the myriad of behavioral and psychiatric issued seen in Keys’ study.  It was administered under supervision as any medical treatment should, to monitor the progress of the patients already existing condition, to assure the physiologically desired results are occurring, and to watch for changes and complications.  It seems as if the audience is using the broader term of ketosis as synonymous with the range of therapeutic ketosis used for epilepsy treatment.]

ketosis is exceptionally challenging for adults

[What diet isn’t challenging? Why do you assume that benefits are only gained if the ketogenic state is constant?].

“without a nutritionist guiding you it’s still hard to get down into ketosis.”

[Staying under 30 grams of carbs per day will do it for most within a week, otherwise drop carbs more or fasting will do the trick for almost anyone.  Hard as in difficult life change maybe true, but difficult as in complex is outright incorrect.]

It’s not exactly clear why ketosis seems to improve epilepsy, but it seems to have something to do with the brain’s use of ketone bodies in place of glucose, which only happens when you’re essentially in starvation mode.

[Starvation is not a well defined state – be more specific as to what is meant.  An individual can be well fed state while in deep ketosis which would make starvation mode as a driver of ketones a misnomer at best.]

“Keto is not easy to maintain, it’s not a palatable diet,” says Andrea Giancoli, a dietician and nutrition consultant in California.

[The diet is as palatable as you make it.  Eggs, meat, butter, non-starchy veggies, and plenty of other palatable foods disprove this point.  Please stop using opinions as a scientific reasoning as appeal to authority is a logical fallacy…  Your name is Popular Science. Please site scientific studies to make points.]

“Getting 80-90 percent of your calories from fat—which is what’s required for keto”

[No it isn’t – You are in ketosis while complete fasting, http://diabetes.diabetesjournals.org/content/10/1/22, Ketones are present in protein sparing modified fast when LITTLE TO NO DIETARY FAT is consumed, http://diabetes.diabetesjournals.org/content/25/6/494.short]

“—is actually difficult. It involves eating a lot of rich, heavy foods with little variety—think fatty meats and gravy [isn’t gravy thickened with flour] on cauliflower.”

[or tons of other foods, https://www.ruled.me/ketogenic-diet-food-list/. At this point of the article it is pretty obvious this particular person chosen as the expert has little experience or study on ketogenic diets outside of their knowledge that it is different than the standard American diet]

You’re only allowed 10 to 15 grams of carbohydrates per day, and though many dieters stretch that to more like 20 or 30 grams that’s still only about one banana. A single apple could also get you past that limit depending on its size.

[Net carbohydrates as fiber really doesn’t interfere with ketosis in any science I have seen and logically shouldn’t given it doesn’t affect blood sugar or stored carbohydrate levels.  Also, it would be a huge apple if you mean net carbohydrates.]

But the real problem isn’t going over your carb limit—it’s the protein . “If you’re eating a lot of protein, you’re breaking that down into carbs,”  Giancoli explains. Your body is in desperation mode on keto, she says, and without a reasonable supply of carbohydrates coming from grains and fruits, you’ll start breaking down the amino acids in proteins to make glucose

[The misinformation about protein and ketosis is quite rampant throughout this paragraph. Increased protein consumption does not result in increased gluconeogenesis http://diabetes.diabetesjournals.org/content/62/5/1435].  Gluconeogenesis is demand driven as opposed to supply driven.

For a more specific look at protein and keto see my previous post:  Protein Turns Into Sugar Myth (Keto Misconceptions Pt 2)

“Glucose, though it sounds like a scary sugar, is your body’s primary source of fuel. Too much isn’t good for you, but you need some just to allow your cells to function normally.”

[Primary meaning first used and generally accepted as true, but not the same as preferred.  While this is not an untrue statement it is usually cited as a means to justify higher dietary intake of carbohydrates without citing studies as to specific health effects of diets differing in macronutrient composition.  Glucose as the first fuel source does not seem to be the case when Acetate is present, so it could be argued that Acetate is the “primary” fuel source even though high alcohol consumption is pretty universally accepted as an unhealthy dietary choice. https://www.ncbi.nlm.nih.gov/pubmed/10539756]

“And when you’re starving, your body will start to break down protein just to get those sweet, sweet carbs”

[The same myth as the previous paragraph still persists.]

Of course, you have a source of protein in your body already: your own muscles. “When in starvation mode, your body breaks down muscle in your body,” says Giancoli. “Ketosis is a way of trying to preserve that protein. It’s not ideal, but it’s your body’s way of saving you.”

[Again, starvation mode is not well defined or the same as ketosis.  The word “ideal” is a generalized term that needs parameters to determine its specific meaning.  Keto diets have shown similar lean body composition changes as non keto diets with similar caloric and protein make-up and show greater lean mass gain when glycogen loss is accounted for (I don’t know what to site as there are many, but there are ton’s so if you want just one I can ask for something specific).  If a person’s main goal is fat loss and body composition change the keto diet may very well be ideal for them. It is not ideal for every person or lifestyle, but it is hard to argue any lifestyle change is ideal without explaining the majority of parameters around the individual’s goal and preferences.]

“If you give your body any more than the absolute minimum amount of protein that it needs, it will immediately break it down into carbs. This is why keto sites often give a guideline for not eating too much protein.”

[Other keto sites do give lower protein guidelines, but mostly because they believe the same incorrect information as this dietitian does and I have addressed previously.]

[More misinformation on protein, plus some bonus misinformation on thermodynamics.]

“Circulating ketone bodies make your blood too acidic.”

[Blood pH stays within normal limits while in ketosis. (Salway JG. Metabolism at a Glance. Oxford: Blackwell Science; 1999.)]

“your body will draw calcium from your bones as a buffer”

[“Hypercalcemia is an uncommon complication of the ketogenic diet, and these children may represent the severe end of a clinical spectrum of disordered mineral metabolism.” (Hawkes & Lavine, 2014) https://www.ncbi.nlm.nih.gov/pubmed/24606099]

“The high fat content in the diet, especially if you’re eating saturated fats, can raise your lipid levels and contribute to developing cardiovascular disease”

[The links between fatty acids and cardiovascular disease are not clear cut and differing fatty acids may have different effects.  Lipid ratios are also a better proxy for cardiovascular risk than individual levels. This is a long topic that I am only briefly touching on here. https://www.ncbi.nlm.nih.gov/pubmed/12716665]

“Without the fiber from whole grains and fruits, you’re also likely to get constipated and have other digestive issues”

[A large dietary change of any type will likely take time to adjust the digestive system.  There is also more fiber in the veggies allowed on keto diets than in the majority of whole grains and fruits.  Low magnesium may also be part of the cause for ketogenic dieters experiencing constipation (https://www.nature.com/articles/1602573).]

“Plus you need fiber to maintain a health gut microbiome, which tends to come from the kind of whole grains that you can’t eat on the diet”

[Again, there are plenty of other fiber sources]

“Neither Giancoli nor any of the other dieticians and nutritionists who evaluated keto for a recent US News & World Report diets ranking would recommend it”

[Appeal to authority fallacy again]

Many of them said they had serious concerns about long-term safety of doing keto,

[Argument from ignorance fallacy.  They have concerns because it is not what they understand instead of being an educated opinion inferred from the current breadth of available data.]




Bistrian, B. R., Blackburn, G. L., Flatt, J. P., Sizer, J., Scrimshaw, N. S., & Sherman, M. (1976). Nitrogen metabolism and insulin requirements in obese diabetic adults on a protein-sparing modified fast. Diabetes,25(6), 494-504. doi:10.2337/diabetes.25.6.494

Fromentin, C., Tome, D., Nau, F., Flet, L., Luengo, C., Azzout-Marniche, D., . . . Gaudichon, C. (2012). Dietary Proteins Contribute Little to Glucose Production, Even Under Optimal Gluconeogenic Conditions in Healthy Humans. Diabetes,62(5), 1435-1442. doi:10.2337/db12-1208

Guetzkow, H. S., & Bowman, P. H. (1946). Men and hunger: A psychological manual for relief workers. Elgin: Brethren.

Hawkes, C. P., & Levine, M. A. (2014). Ketotic Hypercalcemia: A Case Series and Description of a Novel Entity. The Journal of Clinical Endocrinology & Metabolism,99(5), 1531-1536. doi:10.1210/jc.2013-4275

Ketogenic Diet Food List: Everything You Need to Know. (2018, February 10). Retrieved from https://www.ruled.me/ketogenic-diet-food-list/

Mensink, R. P., Zock, P. L., Kester, A. D., & Katan, M. B. (2003). Effects of dietary fatty acids and carbohydrates on the ratio of serum total to HDL cholesterol and on serum lipids and apolipoproteins: A meta-analysis of 60 controlled trials. The American Journal of Clinical Nutrition,77(5), 1146-1155. doi:10.1093/ajcn/77.5.1146

Murakami, K., Sasaki, S., Okubo, H., Takahashi, Y., Hosoi, Y., & Itabashi, M. (2006). Association between dietary fiber, water and magnesium intake and functional constipation among young Japanese women. European Journal of Clinical Nutrition,61(5), 616-622. doi:10.1038/sj.ejcn.1602573

Siler, S. Q., Neese, R. A., & Hellerstein, M. K. (1999). De novo lipogenesis, lipid kinetics, and whole-body lipid balances in humans after acute alcohol consumption. The American Journal of Clinical Nutrition,70(5), 928-936. doi:10.1093/ajcn/70.5.928

Werk, E. E., & Knowles, H. C. (1961). The Blood Ketone and Plasma Free Fatty Acid Concentration in Diabetic and Normal Subjects. Diabetes,10(1), 22-32. doi:10.2337/diab.10.1.22


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About Roger James CSCS, NSCA-CPT

I am a trainer (Certified Strength and Conditioning Specialist®, NSCA-Certified Personal Trainer®, NASM Golf Fitness Specialist), coach (USAW Sports Performance Coach), and now blogger with a passion for fitness, health, and performance. My love for the gym began as a way to get stronger and better at sports. While my early training packed on strength it also packed on unhealthy weight. After a pectoral injury made strength training take a back seat, I focused on my health and losing weight to go from 270lbs to 200 in about 3 months time. I favor evidenced based training and lifestyle choices to build not just the body clients want to see in the mirror, but that have the strength and ability to live life as actively as they desire. This site is a way for me to help others on their health and wellness journey.  It is my goal to provide quality material to help educate and expand peoples thinking about fitness, health, and wellness.  I am not a doctor and do not claim to be.  The information provided on my site is there as an educational tool so that others can make informed decisions about how to live their life.