I’ve lived through many cycles of fad dieting and one observation I’ve made is that the minute a diet becomes mainstream and especially when food companies latch onto it, the diet often transitions into a dark phase.  One of the problems with diets is that although initially the motivation for success might be preventing or reversing a chronic health condition, the focus often rapidly shifts to more cosmetic goals like lowering dress size, waistline, and body fat, even when biometric goals are reached.

The intense and often desperate drive to achieve these goals is often the crossover point when a diet like keto or even intermittent fasting goes from a therapeutic intervention or potentially healthy lifestyle change to a borderline or full blown eating disorder.

Don’t get me wrong.  When the ketogenic diet is done properly, it can reverse diseases like diabetes in record time, in most but not all individuals.

The keto diet is not a panacea and I’ve had patients follow the healthiest version of a ketogenic diet where they diligently tracked their ketone levels and had little to no benefit at all.  In this post I’ll explore some of the pitfalls of the keto diet, and many of these principles can also be applied to fasting.

Is Keto Good or Bad?

This is a really common question I get during talks and in the clinic by physicians and patients.  I’m not going to dig deep into the science of ketosis here, but rather provide a higher level perspective. The state of ketosis is achieved when carbohydrate intake is low enough to trigger the liver to produce substances called ketone bodies, which can be a magnificent fuel source.  I’m pretty convinced based on existing and emerging research that ketones have myriad health benefits and can be a useful tool to promote longevity and enhanced performance.  However, the path to ketosis can vary.

The majority of patients who tell me they are on a “keto diet,” are actually not in a state of ketosis.

They typically aren’t measuring ketones and after I take their diet and exercise history, I’m even more certain they are not producing ketones in the blood due to excess carbohydrate intake and insufficient physical activity.

Others think they are on a keto diet because they are consuming a whole host of keto-labeled foods (keto granola, ice cream, bars, shakes, etc.) even though their overall carbohydrate intake is far too high to drive ketone production.

Consuming even mildly excessive carbohydrates with a high fat diet disguised as “keto,” produces the double-edged sword of elevated insulin levels driving both carbohydrates and fat into body fat storage and excess cholesterol production.

This type of “pseudo-keto” (high carb and high fat) diet may actually be more damaging than most baseline diets due to the cumulative impact of excess carbohydrate and fat intake which together may do more harm than either alone.  This is why measuring ketones in some form (preferably blood) should be considered mandatory if you are truly going on a keto diet.

Right now the ketogenic diet is the most popular diet in the world.  The outcome of the diet is the state of ketosis, however the path to ketosis in the mainstream world is associated with some of the following labels, behaviors, and outcomes:

  • High saturated fat (butter, ghee, coconut oil, lard, etc.) in someone who can’t handle such an energy surplus
  • Unrestricted red meat (carnivore, etc.), often poor quality
  • Micronutrient deficiencies due to a lack of dietary diversity
  • Dietary fiber deficiency due to a lack of varied plant-based foods, which in turn causes a lack of gut microbiome diversity
  • Excess protein intake in mostly sedentary individuals

Your chosen path to achieve ketosis can enhance your health or potentially ruin it.  If in your pursuit of ketosis, you choose to fast extensively and subject yourself to one or more of the above side effects, then I don’t consider your ketogenic diet to be a healthy one.

If you are at high risk of heart disease already and you pursue a predominantly saturated fat based diet with a surge in your LDL cholesterol, I cannot condone your path to ketosis as a wise one.

I know there are self proclaimed experts out there who confidently say LDL never matters as long as insulin resistance doesn’t exist.  That’s a bold statement that is not currently driven by a shred of reliable evidence.

I have a small number of patients who were on a high fat, ketogenic diet with very high LDLs, but no other signs of insulin resistance, who had coronary artery calcification, a marker for heart attack causing plaque.  Again, this was a small number and I have had far more individuals in the same situation with no signs of plaque.

This is my own anecdotal experience which is not sufficient to make a conclusion either way, so for now I would err on the side of caution and wait for high quality studies to help guide my decision making.  If you are not familiar with heart scans and their role in risk stratification, read my post here.

I do agree, as I’ve stated in my book and prior blog posts, that LDL cholesterol levels on a standard lipid profile have been overemphasized as a central causative agent for heart disease.  This is clearly not the case and there is much more nuance to interpreting cholesterol levels in the context of other heart disease risk factors.

Should Keto be a Permanent or Transitional State?

Many individuals wonder if they should remain lifelong keto or do it intermittently.  For my average patient, intermittent ketosis seems to be the most sustainable strategy.  That’s what I personally do.  After monitoring blood sugar and ketone levels for years, I’ve developed a pretty good intuitive sense of when my body needs to be in ketosis to remove excess energy stores (aka body fat), and when I can refuel again.  This is an intuitive skill I try to get all of my patients to achieve so they aren’t constantly tethered to devices and sensors, or relying on excessive laboratory testing to guide lifestyle choices.

I also have patients who have remained in ketosis for years and they are thriving in all parameters of what I consider optimal health.  There is no compelling evidence to date for me to convince them to downshift to intermittent ketosis or go off the ketogenic diet altogether.  The decision is highly personal and extremely variable.

Should Keto Be Medically Supervised?

I’ve come to the conclusion now that for most individuals the keto diet should be done under the supervision of a health practitioner (dietitian, physician, etc.) who is experienced and knowledgeable about how to prescribe a nutrient-dense, whole foods diet that simultaneously helps the body produce ketones without producing the aforementioned side effects.

Unfortunately in my experience and from talking to colleagues, the casual or lay approach to keto dieting does not achieve these goals in most individuals.  This is the darker shade of mainstream dieting that I referred to at the beginning of the post.

I’ve had many women in particular develop hormonal disturbances, particularly thyroid issues from an overly strict, nutrient deficient keto diet.  Instead of the magical “fat-burning metabolism” promoted widely, they have developed a starvation metabolism instead and are often left hungry, tired, depressed and frustrated, while their male spouse or partner appears to thrive effortlessly on the diet.

These well-intentioned spouses often tell their wives to fast longer or go even lower carb, giving the impression that their wives are not trying hard enough. This can leave women even more frustrated and produce marital tension which I’ve witnessed during some of my clinic visits.  Sound familiar?

Like I said, the minute any diet gets trendy and mainstream, that’s when we all need to raise our red flags.

Individuals and health promoters eager to carve out their own niche often lose objectivity and focus on limited elements of a healthy diet.  More disturbing is how the food industry catches on quickly and starts producing processed foods (shakes, bars, cereals, etc.) that are prominently labeled with the diet trend front and center, to lure people away from wholesome natural foods.

Closing Thoughts

A big picture point is that the keto diet is generally a high energy, lower insulin diet.  The lower insulin part is a good thing since chronic and excessive hyperinsulinemia drives disease.  The high energy part, coming mainly from the relatively higher intake of dietary fat is where people can get into trouble.

Most of my patients are quite sedentary and insulin resistant.  They lack the metabolic horsepower to burn such a large amount of high energy fuel from dietary fat.  They might be tantalized by instagram photos of keto dieters with lean bodies consuming fat bombs and other delectable “keto-approved” meals, snacks, and desserts, but they overlook the fact that many of these health leaders are also exercising vigorously and their energy intake matches their ability to burn these higher energy foods for fuel, rather than store them as body fat or expel them as excess cholesterol particles in the blood.

This is prime time for us to pause and reflect on what the original intent of the keto diet was, and to where it has rapidly accelerated and in many cases degenerated, thanks to big food and overzealous keto evangelists.  The good news is that more doctors and health care practitioners are thoughtfully prescribing the ketogenic diet, in addition to companies like research-based Virta health, which is simultaneously conducting solid scientific research while providing well designed ketogenic dietary interventions.

My Prior Related Posts

7 Top Concerns About the Keto Diet

Is Intermittent Fasting Overrated and Harmful to Health?

Insulin Training and Glucose Variability