My Response to Paleo-Mom’s “Adverse Reactions to Ketogenic Diets”

My response to this blog post:

Short version:

Keto is not a good fit for everyone. But most people can get the benefits without any of these adverse reactions if they do it right. Also, most of the adverse reactions she reports are from studies involving children eating ketogenically to treat intractable epilepsy – so they were quite ill from before this diet.

I appreciate Keto-Mom’s balanced approach and correct understanding of ketogenic diets.

Very long version:

I was previously not familiar with PM (as I will call Paleo-Mom), but have had several people from different circles of my life ask about this article.

I have been eating a ketogenic diet since March 22, so 1½ months as of this writing. In that time I’ve read a lot about it & done a lot of research. I will give off-the-cuff responses to Paleo Mom’s statements. If anyone wants details or references behind what I’m saying, please ask me – I will be happy to go dig them up. But I’m not going to spend a lot of time beforehand turning this into a well-referenced dissertation.
PM: “… the discussion of the pros and cons of this high-fat, low-carb, low/moderate-protein diet.”

An excellent start. I agree we need to have this discussion. Confirmation bias is a huge problem, particularly in the sciences which inform human behavior (see my last post) – we need to be careful to consider the cons of any way of doing things we have chosen.

Having initially been very skeptical of the ketogenic diet, and having unsuccessfully tried Atkins in 2004 before my current attempt (which is going very well), I believe I am in as good a place as anyone to consider both sides.

I also appreciate that she actually understands what a ketogenic diet is – it is very low carb but not high-protein. I also appreciate that she doesn’t conflate dietary ketosis with the deadly ketoacidosis that can occur in type-1 diabetics.

PM: “The origins of the ketogenic diet …Hippocrates in 500BC …”
They also include ancient people such as the Inuit of arctic North America, the Masai of east Africa, and the Sioux of South Dakota, who ate meat almost exclusively for centuries or millennia.
More here (ok… maybe a few references to references to references):

An Arctic Explorer named Vilhjalmur Stefansson, had lived among the Inuit in the 1920s. He was called a liar for claiming he could stay healthy on a diet of just meat and fat. To salvage his reputation, he allowed himself to be locked up in Belleview Hospital in New York City for most of the calendar year of 1928. Actually, he was only locked up for three months and then monitored closely when he went out. For that whole year he ate a diet consisting of meat and fat which was about 15% protein and 85% fat, a very high fat diet with no fruits and vegetables, no vitamin pills, and he did not develop scurvy.

But kudos for PM’s excellent summary of ketogenic diets in the treatment of epilepsy.

Also note that even this keto critic acknowledges it “… may at least partially alleviate … Alzheimer’s…”

PM: “… any study that allows for keto-adaptation, which takes up to a month, can be considered long-term.”

Excellent – glad to see she understands that you can become ketotic in a matter of days, but that adaptation requires 3-6 weeks.

Now we get to the meat: the list of adverse reactions. Most of these fall into three categories:

1. The sufferers have a minority condition (such as a food allergy or inability to process a particular amino acid) which means keto is not a good fit for them, or that they need to avoid particular foods but can still successfully eat ketogenically without adverse reactions.

2. They are doing it wrong – not eating “a well formulated ketogenic diet” (to quote “P&V”: Doctors Phinney & Volek, authors of New Atkins for a New You, The Art and Science of Low Carb Living, and The Art and Science of Low Carb Performance, and their blog

PM agrees with me here: “some of the above adverse reactions can be prevented with careful choice of foods and/or targeted supplementation (such as nutrient deficiency).”

3. A certain percentage of people are going to get all of these reactions. That they got them while doing a particular activity does not mean the activity caused the reaction. This is especially true for people eating low-carb – low-carb helps people with a lot of different conditions (metabolic syndrome, PCOS, epilepsy, kidney stones, etc etc) so people predisposed to many disorders switch to keto because they were sick … even if they keep being sick, it may be that they are less sick on keto than they otherwise would have been.
PM agrees with me here too: “it’s not typically the robust healthy person who experiments with ketogenic diets to improve their health”

I am going to list each one, and then say what I’ve read about them from proponents of ketogenic diets:

PM: “Gastrointestinal disturbances (diarrhea, vomiting, nausea …”

If a person unaccustomed to eating a lot of fat suddenly starts eating a lot, it can cause these types of distress. That is a transitory reaction for most people; PM prefaced this section by clarifying these are primarily long-term adverse reactions. So: long term, while a small amount of Ω6 PUFA (omega-6 poly-unsaturated fatty acid) is essential (we need it and can’t make it), only a small amount is needed, and it should ideally be evenly balanced with Ω3 PUFA. Western diets typically include FAR too much Ω6 and not enough Ω3. When someone someone switches to keto, especially if they believe the mistaken claim that SFA (saturated fatty acids) are bad, they are likely to eat far more Ω6 PUFA than they had been before keto. This causes the digestive problems PM mentions, as well as other problems (see “inflammation” below). Phinney discovered this in trials of elite athletes eating keto in the 1970s or 1980s – he fed them a large portion of their fat in the form of soy-oil-based mayonnaise, which has a large proportion of Ω6. After a week or two of that, the athletes cut their consumption of the mayo way back because it became distasteful to them. Mayo made from canola (yes I know there are other problems…), olive, avocado, or coconut oil is low in Ω6 and more appropriate.

Solution: a ketotic person should eat most of their fat as SFA and MUFA (mono-unsaturated fatty acids such as are found in olive oil and lard), and Ω3 (from fish oil – vegetable sources of Ω3 are better than Ω6 but inferior to fish oil). We should sharply limit Ω6 – it is virtually impossible to go too low while eating a high proportion of fat. And ITF (inflammatory trans-fats) from hydrogenated & other processing should be completely avoided (as opposed to healthy, natural trans-fats that are also cis-fats such as those found in butter from grass-fed cows).

PM: “… constipation”.

This is a well known effect of not eating enough sodium. High-carb diets cause the kidneys to retain sodium; thus the AHA’s misguided advice to sharply limit sodium intake to 2300 mg/day or even 1500. (This is harming even people on high-carb diets, but that’s for another post). Low-carb diets cause the kidneys to excrete more sodium, so ketotic people must eat more like 5 g/day, or the body will compensate by also excreting potassium and other electrolytes to keep them in balance with sodium. The Inuit solved this problem by picking sea ice with a moderate amount of salt to melt for cooking. The Masai solved it by drinking blood. Like vampire bats, they would nick their cattle, drain maybe half a cup of blood to drink, then allow it to heal. We in the west, of course, find it easy to get enough salt if we just know to do it.

PM: “Inflammation risk”
Too much Ω6 is inflammatory. Eat less Ω6, and more SFA, MUFA & Ω3 (see above).

PM: “Kidney stones”

This can be caused by eating too much protein, which many people do if they try to eat low-carb and low-fat simultaneously (not a good plan).

It can also be caused by not eating enough potassium, magnesium & other electrolytes, which draws sodium & calcium out of the body.

Eating too much oxalate and refined sugar – especially fructose causes kidney stones – these are all avoided by people eating ketogenically. Some switch to keto because they (being predisposed to kidney stones) got kidney stones from eating those foods.

PM: “Muscle cramps or weakness”
This is a well known consequence of not eating enough magnesium.

PM: “Hypoglycemia”
Many people start keto to resolve the symptoms of type-II diabetes – and it works FANTASTICALLY. Many people – especially in the early stages – can completely get off exogenous insulin and quit daily testing their blood sugar by sharply limiting carbs. This makes sense, as carbs cause rapid, sharp insulin spikes, while protein causes small, longer duration insulin swells, and fat does almost nothing to insulin.

But if a diabetic accustomed to eating 50g carbs at every meal and taking the appropriate drugs to counteract this carb-overload suddenly stops eating carbs, the drugs can indeed cause blood sugar to go too low.

Interesting tidbit – 40 or 50 years ago, some scientist did a trial where he took some keto-adapted people (who had been eating keto for at least 4 weeks) and injected insulin until their blood sugar levels dropped into the 20s (this would put glycolic people – those primarily using glucose for fuel – in a coma). They were all fine and clear-headed.

PM: “Low platelet count”
This is new to me… I’ve spent some time on various keto / Atkins / LCHF (low-carb high-fat) discussion boards and never heard anyone mention this. I see from the study link in the PDF that this was found in epileptic children eating a 4:1 ketogenic diet (80% fat). 1% of the children were reported as having thrombocytopenia. Seeing as thrombocytopenia is defined as having a platelet count below the 2.5th percentile, it looks to me like this was a lower number of incidents than would be expected.

PM: “Impaired concentration/cognition, or mood”

Most people doing keto report the opposite, because ketones provide a steady supply of fuel to the brain regardless of when we’ve eaten, as opposed to a glycolic person whose brains are adapted to use glucose as its primary fuel – if they go too long without eating, they get fuzzy headed. This is the same thing as “bonking” or “hitting the wall” that long-distance athletes experience, but ketotic endurance athletes avoid.

It appears these adverse reactions were reported in studies of epileptic children – those who had brain disorders prior to eating keto, so I doubt eating keto caused these problems.

PM: “Renal tubular acidosis”

I’m pretty sure eating keto does not cause this.

PM: “Nutrient deficiency, Disordered mineral metabolism”

Yes – it is possible to not get the nutrients you need eating keto, just like with any diet. You need to get your vitamins, minerals, essential fatty acids, and essential amino acids. It’s easy to get these nutrients eating a lot of meat, but vegetarians eating keto must be especially careful.

PM: “Poor growth in children”
The people I mentioned above who had been eating meat almost exclusively for centuries (Inuit, Sioux, Masai) were much taller and more muscular than the Europeans who initially came into contact with them. This leads me to believe poor growth is due to “doing it wrong”. It may also be associated with unhealthy children, as most Western children are not put on ketogenic diets unless they have epilepsy, PCOS or other problems.

PM: “Skeletal fracture, Osteopenia/osteoporosis”

Again, we need to get enough electrolytes – sodium, potassium, magnesium, and calcium.

PM: “Increased bruising”

I have seen this on the boards I frequent … may really be caused by keto …

PM: “Sepsis, infection, bacteria overgrowth, Pneumonia

Again – this was from a study of people with intractable epilepsy. I’m not aware of these being more prevalent than average for people eating keto to control metabolic syndrome or PCOS.

PM: “Acute pancreatitis”

Again, people often switch to keto due to a diagnosis of metabolic syndrome or diabetes, which means they’ve been stressing their pancreases before switching. It can also be caused by not drinking enough water.

PM: “Long QT intervals, Heart arrhythmia”

Some people switch to eating keto because they have hypothyroidism – keto relieves some of the symptoms of that disorder, but it also causes long QT intervals.

PM: “Cardiomyopathy”

Again, people on the road to heart disease often switch to keto. It delays heart disease in far more people than not. We are more and more learning that cardiomyopathy is an inflammatory disease, so people eating too much Ω6 or ITF (see above) could increase their risk.

PM: “Shift towards atherogenic lipid profiles”

We are discovering that total cholesterol and LDL-C counts not only don’t cause atherosclerosis, they are completely uncorrelated with heart disease! Eating keto will raise total cholesterol, but it raises HDL, which is associated (not necessarily causative though) with good heart health. In many people it lowers plasma triglycerides. People with hypertriglyceridemia are often eating too many inflammatory fats such as Ω6 or ITF.

PM: “Menstrual irregularities and amenorrhea”

I have seen this complaint pretty often on the keto boards I frequent. This one seems pretty legitimate. A lot of people complaining of these real problems switched to keto because they have PCOS – for many people it may be other underlying conditions causing the problem. Or it may be the diet itself for others.

PM: “Myocardial infarction, Death”

Heart attacks! Yes, people eating keto have heart attacks and die. I’d argue that for the vast majority of people doing it right (especially those like me with low carb tolerances), eating keto postpones these outcomes more than eating higher-carb diets.

PM: “… tolerating the detriments to other body systems (such as endocrine …)”
I’d argue that ketosis is beneficial to the endocrine systems of most people, especially the insulin-resistant among us. Even insulin-sensitive elite long-distance athletes are finding their performance improved while eating keto.

I did not read the whole linked PDF at the bottom, but I did search it for the adverse reactions with which I wasn’t already familiar.

Again – if there are any questions, or anyone wants links to a claim I’ve made, please contact me & I’ll be happy to respond.


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