What is a Ketogenic Diet?

So what is a ketogenic diet? Despite its popularity in today’s society, few truly understand what a ketogenic diet is. One of the best definitions I’ve come across is by a colleague of mine who stated that, “A ketogenic diet is one in which glucogenic substrates (non-fiber carbohydrates and glucogenic amino acids) are low enough to force the body to primarily rely on fat as substrate.” The ketogenic diet is traditionally a high-fat, moderate-protein, and very low-carbohydrate diet and through the appropriate balance of these three macronutrients (protein, fat, carbohydrates), we are able to alter our energy utilization and enter a unique metabolic state known as nutritional ketosis.  

Nutritional ketosis, not to be confused with diabetic ketoacidosis, is a state in which the body switches its preferred fuel source from carbohydrates to fat, which results in the production of an additional fuel source known as ketones or ketone bodies. These ketones can be rapidly broken down for energy production by various tissues throughout the body. As stated above, the ketogenic diet allows the body to use an alternative fuel source (i.e. ketones) to meet the demands of the body. The adaptations that allow us to enter ketosis take time, and this transition period is often referred to as keto-adaptation. Once keto-adaptation occurs, you are considered to be “fat-adapted”.


There are several ways in which the body can enter a state of ketosis, with the most common being a ketogenic diet. When attempting to enter ketosis through dietary manipulation, it is essential to keep in mind the recommended fat, protein, and carbohydrate intakes. As with most diets, there is no “one-size-fits-all approach” for a ketogenic diet. The ratios and amounts of each macronutrient of the diet may vary slightly from person to person depending on an individual’s goals and health parameters, such as insulin sensitivity, current body composition, gender, and activity level.

Recall that a ketogenic diet by nature is a low-carbohydrate diet.  In the literature, you may find a “low-carbohydrate diet” being described as one that restricts carbs below 30% (1); however, not all low-carbohydrate diets are necessarily ketogenic (2). Several variations of low carbohydrate diets exist (i.e Atkins Diet) and are also often mistaken as being ketogenic. The main difference between other low-carbohydrate diets and a ketogenic diet is the increased presence of ketones in the blood.


If you recall, a ketogenic diet is one in which glucogenic substrates are low enough to force the body to transition from glucose metabolism to fat burning and to the subsequent production of ketones. Ketogenic.com recommends that a standard ketogenic diet will consist of percentages of your total caloric intake at 70% fat, 25% protein, and 5% carbohydrates, with these carbohydrates coming primarily from fibrous vegetables. For help with developing your personalized ketogenic diet, check out the Keto For You application.

Just as there are the different variations of “low-carbohydrate diets,” there are various types of ketogenic diets. These include the standard ketogenic diet (as mentioned above), cyclic ketogenic diet, targeted ketogenic diet, and therapeutic ketogenic diet.  The first three diets contain similar macronutrient ratios, but differ in the use of carbohydrates. Therapeutic ketosis is different than the other three in that it contains more fat (80-90%) and less protein (10-20%).





The ketogenic diet is often mistaken as a zero-carbohydrate diet; however, carbohydrates should make up between 5-10% of the total caloric intake. As previously mentioned, these carbohydrates should consist of fibrous or leafy green vegetables. These vegetables are included for several reasons.  For one, fiber can be important on a ketogenic diet, making these types of vegetables your best option.  Also, consuming most of your carbohydrates from fiber prevents you from ingesting too much sugar.


Contrary to popular belief, fat is our friend, especially when ketogenic dieting! remake-tableDepending on the specific ketogenic approach, fat is going to comprise 65-90% of total caloric intake. Incorporating high-quality fats is crucial to the success of a ketogenic diet, especially during the adaptation period. For the purposes of a ketogenic diet, high-quality fats are ones that are high in medium-chain triglycerides (i.e. coconut oil, heavy cream, cheese, etc.), which are able to be broken down for energy faster compared to their counterparts, long-chain triglycerides. However, the incorporation of a variety of fats is beneficial, including saturated and monounsaturated fats. Check out our Keto Pie to learn more about common ketogenic foods!



The ketogenic diet is also often mistaken as a high-protein diet. This is likely due to the popularity of the Atkin’s Diet in the 70’s and 80’s. However, a true ketogenic diet consists of protein between 5-25% of total caloric intake, and like fat, this number is dependent on the individual and his/her goal. The reason behind the restriction of protein is the possibility of it being digested and converted to glucose. Protein is made up of amino acids, some of which are ketogenic (aiding in ketone production) and others of which are glucogenic (aiding in glucose production). The amino acids that are classified as glucogenic, when consumed in excess, could convert to glucose through a process known as gluconeogenesis.  Note that depending on goal, some individuals may consume protein at a higher percentage than 25%.

Starting the Ketogenic Diet

There is more to starting a ketogenic diet than simply finding your macronutrients and eating the appropriate foods. To enter the state of nutritional ketosis (0.5 mmol/L or greater), our body must endure what is commonly termed “keto-adaptation.” During this adaptation period, the body adjusts to the dietary changes to make physiological adaptations that allow us to utilize fat for energy production rather than glucose. This period is often the most difficult part of the diet due to some of the typicketoflu-symptomsal side effects individuals may experience. These side effects are commonly referred to as the “Keto-Flu” or “glucose withdrawal”. The Keto-Flu can cause symptoms including headache, fatigue, light-headedness, and brain-fog. In addition, some people may experience psychological complications that affect their mood as well. Several of these side effects can be combated through a well-formulated ketogenic diet, the incorporation of the proper micronutrients, appropriate meal frequency, different workout strategies, and even ketogenic supplements. Measuring your ketone levels with a blood ketone meter (similar to a blood glucose meter) may be important during the early stages of a ketogenic diet so that you can not only tailor the diet to optimize your results but also to make sure your ketone levels are increasing appropriately.

Mistakes of a Ketogenic Diet

Learning how to eat on a ketogenic diet is much different than on other traditional diets or lifestyles. For this reason, first-time ketogenic dieters commonly make many mistakes.


I recommend using a calorie/macronutrient tracker to ensure that you are reaching the appropriate macronutrient ratios. This will be especially important during this initial keto-adaptation period. Another common mistake we see is not sticking with the diet long enough to experience the benefits. As stated earlier, it takes time to adapt to the ketogenic diet. If an individual does not stick with the diet long enough, they will not experience these positive adaptations. Alcohol consumption is another reason for failure to achieve ketosis. While alcohol itself could potentially increase ketone production, most alcohols are accompanied with sugar. Certain types of alcohol, such as dry red wines (like our friends from Dry Farm Wine), may be better tolerated following adaptation to the diet.  However, excessive alcohol intake should be avoided during the early stages of the diet.  Letting carbohydrates creep up too high may be one of the most common reasons for failure to achieve ketosis.  This is especially true  in individuals who are incorporating nuts and nut butters into their diet, so be careful when consuming these types of foods. While these foods do have a place on a ketogenic diet, they also contain lower amounts of carbohydrates.  They may also be very easy over-consume, which can be detrimental to the success of the diet. For this reason, I recommend weighing out your food until you get a hang of the diet and various “sneaky” carbohydrates that appear in some foods like nuts.

Benefits of a Ketogenic Diet

The benefits of a ketogenic diet go much further than just weight loss (4).

Body Composition:

The ketogenic diet has the ability to drastically alter our body composition. If you understand that ketones are produced as a result of increased fat oxidation, then you can understand why the ketogenic diet can result in the loss of body fat (5). In fact, once adapted, ketogenic dieters burn, on average, three times more fat during exercise when compared to non-keto-adapted individuals (6). Additionally, the ketogenic diet has the ability to preserve lean body mass simultaneous with the decrease in body fat, even when matching for protein intake (2,7).


People think that the ketogenic diet is a new diet or a fad; however, the diet has actually been around for over a century! In fact, one of the first uses of the ketogenic diet was for the treatment of drug-resistant childhood epilepsy. Since this early application, it has been found that the ketogenic diet can serve as a potential alternative therapy/aid to a variety of diseases, including many neurological disorders (e.g. Alzheimers and Parkinson’s), metabolic disorders (e.g. diabetes and metabolic syndrome), and even cancer (8)!


The ketogenic diet has also been shown to improve certain aspects of athletic performance. While data is limited on its effects on strength (9), the ketogenic diet has been shown to have a significant, positive impact on endurance performance, due to the increase in fuel availability that results from ketogenesis (i.e. the production of ketones).


Is Keto For Everyone?:

While there are many benefits associated with the ketogenic diet, it should be noted that the diet may not be for everyone. Certain individuals who have disorders that prevent them from digesting fat or breaking down fat for the production of ketones may want to avoid a ketogenic diet and consider other low-carbohydrate approaches. Such conditions include pancreatitis, impaired liver function, gallbladder disease, gastric bypass surgery, and kidney failure. In addition, more data is needed on performance athletes. To date, research has shown that individuals who are insulin sensitive tend to get similar adaptations regardless of their dietary intervention. For those individuals, food preferences may be a better indicator of what would be ideal for them (10).

Ketosis Contraindications

What Happens if I Fall Off the Diet?:

One of the issues with a ketogenic diet is that failure to adhere can have a negative impact on body composition and adaptations. I often see people come off a ketogenic diet and rapidly reintroduce carbohydrates. This is commonly accompanied by excessive weight gain, as evidenced by a study in preparation for publication. For this reason, when coming off a ketogenic diet, I recommend first increasing protein and lowering fat and then slowly reintroducing low-glycemic carbohydrates.  Also, more research is coming out on exogenous or supplemental ketones which may be beneficial to help maintain ketosis.

Do I Have to Stay on the Ketogenic Diet Year Round?:


While we do recommend that you stay on a ketogenic diet for long enough (at least 3+ months) to experience some of the benefits of the diet, it does not mean that you have to stay on the diet forever. In fact, a study by the great researcher Paoli demonstrated that cycling off a ketogenic diet with different stages of low carbohydrate diets can be a great way to maintain the weight loss that occurred during the ketogenic phase (11).  Note that some researchers suggest that additional adaptations to the diet can occur after longer adherence to the protocol.


Rapid Weight Loss:

If you are familiar with dieting, then you have probably heard that rapid weight loss is not the best approach and that the weight loss should occur at a steady pace. During the initial stages of a ketogenic diet, weight loss can be accelerated, but this usually is not a reason for concern. While some of this initial weight loss in the first week or two is coming from fat loss, much of it comes from the body excreting more water and lowering carbohydrate storage as a result of carbohydrate restriction.


Rapid Strength Loss:

If you are continuing to exercise during the adaptation period, which is recommended, you may experience an initial drop in your strength. Most individuals will be very concerned with this and may even stop the diet at this point; however, once keto-adapted, we typically see this strength come back.  Remember that the adaptation period consists of your body altering its energy source.  Once this has occurred your body will likely have the energy to return back to normal strength, so fight through the adaptation!



To effectively start a ketogenic diet, I recommend going all in. It is common to see individuals try to taper down their carbs and increase their fat prior to starting the diet; however, I feel that it is easier to just jump in the water, rather than just dipping your toe in. To start the diet, remember to check out our Keto For You application!

After you have calculated your target macronutrients, it is time to plan out your meals. This step can often be stressful for first-time users, but it does not have to be as difficult as it is often made. Here is my step by step approach to putting together a ketogenic diet.

While this may seem rather restrictive or even repetitive, this approach may not need to be taken throughout your ketogenic dieting experience. Once you have spent time learning about the diet and how your body handles different foods, you will get better at putting meals together without weighing or even tracking your macronutrients.  However, until you have more experience, I recommend this approach to ensure that you are adapting to the diet as quickly as possible.

My final recommendation for starting the diet is to continue to train hard!  While your motivation or energy to train may be down during the initial stages of the diet, exercise can help you get into ketosis quicker! Grit your teeth and get some exercise in!

The purpose of this article is to provide a building block for your understanding of the ketogenic diet. To gain an even deeper understanding of the information provided here, check out the links presented throughout the article, as they will serve as a tool to better understand the history of the diet, how to optimize the diet, and the many applications of the diet. In mainstream media, the ketogenic diet often catches a bad reputation due to its high-fat content and “restrictive” nature. Throughout this website, you will find content providing information on why these claims are not only incorrect but in fact completely irrational. Our goal is to raise awareness about the ketogenic diet and provide the community with the tools necessary to see the many benefits that can be experienced during a ketogenic diet!

7 Replies to “What is a Ketogenic Diet?”

  1. Thank you for a clear and succinct article. This will be my reference to share when being a resource to those interested in a Keto lifestyle!!

  2. Straightforward and simple to understand with useful infographics. This is a great resource I’ll share with others interested in the ketogenic lifestyle. Nicely done Chris!

Leave a Reply

Your email address will not be published. Required fields are marked *