Background on The Ketogenic Diet

Before all the ketogenic diet enthusiasts come after me for writing this blog post, I do want to let you know that I am actually in nutritional ketosis while writing this blog, so please don’t throw zero carb eggs at my windshield.  I’ll cover the ketogenic diet in more detail in a future post, but because this diet is spreading like wildfire and most of the online information out there treats it like the diet to end all diets, I wanted to share some of my top concerns first based on clinical and personal experience.  Having this knowledge will also help you be more successful if you do decide to give the keto diet a try.

If you have no clue what the ketogenic diet is, then my brief description is that it’s a diet that makes our body produce a chemical substance called ketones, an energy source for our cells. Think of ketones as an alternate macronutrient in addition to carbs, protein and fat.

Since ketones are such an effective source of energy for our brains and muscles, when we enter a state of nutritional ketosis, we no longer physiologically need or psychologically crave the abundant amounts of fat-storing carbs that make up a typical diet.  

The fastest way to induce ketosis is to severely limit dietary carbohydrate intake to less than 50 grams daily and in some cases you may need to go as low as 30 grams or less (especially if you are mostly sedentary), while also restraining protein intake and then liberalizing healthy fat intake, which can make up 70-80 percent of your diet.

Advantages include rapid fat burning, enhanced cognitive function and the potential to reverse chronic conditions like Type 2 diabetes, to name a few.  I’ll discuss some of the exciting research around the benefits of keto in the future, but right now let’s focus on some of my reservations since most people are jumping into this diet in a way that may compromise rather than benefit their long term health.

Concern #1-Nutrient deficiencies

Certain nutrients are lost when you are in ketosis and others are missed because when your body has the ability to go long periods without food, you can become deprived of essential nutrients.  Some examples include:

  • Electrolytes like sodium, potassium and magnesium are typically lost during ketosis.  Our body needs these electrolytes, especially magnesium, to produce energy
  • Water loss also occurs from ketosis, so staying hydrated is key
  • Fiber is often lost if people use keto as an excuse to eat mainly meat and fat, with very little plant-based foods
  • Phytonutrients are the other key missing ingredient in addition to fiber when keto dieters don’t eat a wide diversity of vegetables.  Phytonutrients are powerful plant-derived chemicals that lower the risk of heart disease, cancer, neurodegenerative disorders like Alzheimer’s disease and much more. 

The Fix:  

  • Stay very well hydrated, add sensible amounts of a mineral-rich sodium like pink himalayan salt, and consider adding broths to combat sodium depletion.  My high blood pressure post mentions the exaggerated link between natural sodium intake and elevated blood pressure, but keep in mind that some people’s blood vessels are salt sensitive so do monitor your blood pressure if you have hypertension and are adding sodium to your diet. 
  • Eat multi-colored plants (not just greens) and very nutrient dense foods like spices, organ meats, shellfish, fermented vegetables and bone broth.  Since you will be eating far less often, make every bite count!

Concern #2-Eating disorders

People on ketogenic diets are often obsessed with minimizing body fat as much as possible, almost to a detriment.  Carrying some body fat is ok, but if you look at the books and blogs of most keto diet authors and leaders, they typically sport 6-packs and single digit body fat percentages.  

Such images can make us common folk feel pretty darn inadequate.  Also when individuals experience some of that body fat melt away, they get hooked and want to shed more at any cost.  

The incessant drive to keep lowering carbs, to fast longer, and spike ketone levels can often lead to a pathological obsession.  If you’re already a Type A person, this diet can sometimes take you to the brink of insanity.

I also want to warn parents of teens about the keto diet.  Many teens who are already very susceptible to eating disorders and already have developed a fear of food, may find the keto diet perpetuating an even greater degree of food phobia.  Since children and teens have additional caloric and nutrient needs for growth and development, a restrictive keto-style diet may not be appropriate.

Eating disorder. Cropped image of girl eating lettuce

The Fix:  

  • Set realistic goals that promote optimal health, mood and energy levels over trying to drive body fat down to the lowest number possible.  
  • If being ketogenic requires too much effort and is raising your emotional stress, you may need to take a few steps back and consider a more balanced eating plan.  

Concern #3-Mood disorders and fatigue

This is kind of related to eating disorders.  I have had some women conscientiously do the keto diet and develop mild to severe depression and/or fatigue.  Some of this is due to unmet expectations where dieters expect fat to just melt away and are disappointed when progress is less than dramatic.

Such disappointment or mild depression can be worsened by the nutrient and electrolyte deficiencies mentioned before, along with the fact that some women’s brains just need a critical amount of glucose to maintain their mood which the keto diet can’t supply.  

Now don’t give up on keto if you feel some of these emotions in the early stages since that is common and often referred to as the “keto flu.”  Give keto at least 3-4 weeks before making a final decision on whether keto is not right for you.  However, if the initial symptoms are truly unbearable despite adequate hydration and electrolyte replacement, then I don’t recommend you continue.  The other thing to be aware of is that the keto diet, prolonged fasting, or any excessively restrictive diet may impair thyroid function.  An underactive thyroid from keto or severely restrictive dieting can produce fatigue and other related symptoms.  Check out my post on thyroid disease here for more information. 

Feeling drained from all her efforts

The Fix:  

  • Be sure to stay hydrated and avoid electrolyte and nutrient depletion as discussed.  
  • Carb refeeding 1-2 times a week, where you take in more liberal amounts of healthy carbohydrates (sweet potatoes, fruits, plantains, etc.), preferably after a heavy workout, can help correct mood swings for some.  However don’t overdo carb refeedings in the early stages when your body is getting adapted to keto.  It may stall progress.  
  • Be sure to get enough sleep and manage stress levels with some mindfulness and gratitude practices.
  • Make sure some of your dietary fat is coming from Omega-3s, preferably from cold-water fatty fish, which can help stabilize mood.
  • Don’t overexercise (see concern #6 below)

Concern #4-Cholesterol surges

The ketogenic diet can dramatically lower cholesterol numbers like triglycerides and boost healthy HDL levels, however some individuals are very sensitive to saturated fat and we can see LDL cholesterol levels in some cases skyrocket.  

Now unfortunately some ketogenic dieters with high LDLs often point to the fact that their particle size is type A, which they interpret as giving them immunity from heart disease.  

However, it’s important to understand that even abundant amounts of the less harmful type A LDL can still cause heart disease. 

Blood sample for LDL cholesterol (LDL-C) test

The Fix:

  • Diversify your fat intake and don’t just eat predominantly saturated fat.  
  • Be sure to include monounsaturated fats like olive oil, avocados/avocado oil, nuts and seeds. 
  • Eat significantly more plants since the combination of fiber and phytonutrients can help lower cholesterol.
  • Consider reducing the number of egg yolks you eat per week if the other interventions don’t work since I’ve clearly found some individuals to be “yolk-sensitive.”  Most are not so don’t drop eggs prematurely due to their excellent nutrient profile.  Read my prior post if you have concerns about eggs. 

Concern #5-Non-compliance

The ketogenic diet can be difficult to stick to.  Sometimes people rebound into severe carb binges becauset they just can’t get to a point of satiety by incorporating sufficient dietary fat.  The end result is that their average diet still becomes high in carbs and processed foods in addition to introducing excess fat.  If you’re going to do keto, you must do it right.

Introducing abundant fat into a diet that is still high in carbs (leading to high insulin) can trigger health consequences like heart disease.

The Fix:

  • Transition to lower carb eating first (~100-150 grams daily for most) before going keto so your body has time to adapt.  
  • Measure the carb content of everything you put in your mouth using a free nutrition calculator like myfitnesspal, fat secret or cronometer
  • Remove junk food or other high carb foods from your home, car, office or anywhere else to remove temptations and replace with keto friendly options
  • Plan non-food related social events since parties and get togethers are a common cause of relapse.  If you are eating out, choose restaurants that have plenty of keto-friendly options and if you just can’t pass on the bread basket or dessert, avoid going to restaurants temporarily

Concern #6-Muscle loss

If you don’t manage elevated cortisol from chronic stress and excessive high intensity exercise, then the ketogenic diet can often break down (aka “catabolize”) your muscle.  Now fat loss and muscle loss may lead to weight loss, but losing muscle also lowers your overall metabolism making rebound weight gain inevitable.

I have clearly seen women and some men gain back more weight after they discontinued their catabolic version of the keto diet.  

The Fix:

  • Manage stress and sleep as seriously as you manage carbs when going keto
  • If you are a regular high intensity exerciser, consider scaling back and incorporating more lower intensity activities like walking, hiking, light jogging, cycling, yoga, swimming, etc.  
  • Read my post on exercise which discusses how to improve aerobic fitness through lower intensity, fat-burning exercise

Concern #7-Constipation and impaired digestive health

As mentioned before, many people on ketogenic diets don’t consume enough dietary fiber, which can lead to more constipation.  Often they eat a lower diversity of plant based foods, sticking only to greens primarily. This can compromise gut health and reduce the diversity of bacteria in our colon, which is clearly tied to all types of chronic health conditions.  

The Photo Of Large Intestine Is On The Woman’s Body. People With Stomach Ache Problem Concept. Female Anatomy

The Fix:

  • As mentioned, eat a variety of different fibrous plant-based foods other than greens, while limiting the more starchy vegetables while you remain in ketosis.  
  • Hydrate, hydrate, hydrate.  Take your weight in pounds, divide by two and that provides an estimate of how many ounces of water to consume daily.  So if you’re 180 pounds, that’s 90 oz of water daily.  More if you are exercising and/or in a hot environment.
  • Pay attention to electrolyte losses, especially magnesium, which can cause constipation (see concern #1)
  • Be sure to incorporate some fermented foods to provide natural gut-friendly bacteria
  • Consider taking a probiotic supplement


I’m not thoroughly convinced yet that the ketogenic diet promotes longevity and optimal long-term health for all humans.  Pro-ketogenic dieters like to point out how our primitive ancestors thrived in a state of ketosis. However our primitive ancestors also died early of trauma and infection.  

Ketosis may have helped them fight and flee danger and cope with periods of famine, but I’m not sure how they would do if they lived into their senior years.  Some studies suggest that having a little extra weight later in life may promote longevity.   

I personally engage in cyclic periods of ketosis for a few months out of the year.  I do enjoy the mental benefits and the convenience of not having to eat as often, so I time it for periods of intense writing or other projects.  I might also do it as a cleanse after a vacation or period of dietary indiscretion.

I also avoid prolonged periods of ketosis because I am by nature more type A and need to loosen up all the rules that often restrain me from living more freely.  Some people are able to maintain a relaxed outlook on life while doing keto, but for me it often just creates even more discipline and restraint, especially as a parent who often ends up at school, social and sporting events where staying keto can be a challenge.  

The majority of my patients and readers from around the world have achieved game changing improvements in health without ever being in ketosis.  Just by lowering their carb intake to a more reasonable level that is compatible with their daily activity, by improving stress and sleep, and including nutrient dense foods, they can thrive.  

Remember, you can burn body fat without being in ketosis.  For most individuals just lowering insulin levels through dietary carbohydrate reduction can trigger fat loss without having to enter ketosis.

If you do have a chronic health condition like Type 2 diabetes that has not responded to simply lowering carbs, then considering a ketogenic approach in an effort to reverse it is a valid option.  I prefer that over drugs and in this case would argue that the ketogenic diet may prolong lifespan by eliminating a condition that shortens it. 

However, don’t let the keto craze convince you that ketosis is the only path to optimal health and body composition.  Traditional ways of eating like the Okinawan and Mediterranean diets are two great examples of  non-ketogenic lifestyles that promote long lifespans and excellent quality of life. 


  • Refer to my book for ways to incorporate a lower carbohydrate lifestyle that allows you to transition more easily to a keto lifestyle
  • Join me for a weekend immersive retreat in Scott’s Valley on May 18th with an excellent dietitian to learn more about keto and other effective nutritional approaches, in addition to exercise, stress and sleep management
  • Try my online program which has helped individuals transition safely into a keto lifestyle.  
  • My good friend and publisher, Mark Sisson, has wrote what I consider the best ketogenic book on the market which you can find here.