One of the most common yet unfortunate parts of working in the health industry is the ability for the context and intention of concepts (particularly dietary protocol) to become completely misinterpreted. Currently my personal favorite example of this is the Ketogenic Diet (KD), which is a diet that is used clinically as an evidence-based therapeutic treatment for epilepsy, is being studied as a potential adjuvant therapy for cancer, and most prominently used as a trendy fad diet for individuals looking for a “quick fix” in regard to weight loss.
What is the Ketogenic Diet?
The KD is a diet in which the majority of calories an individual consumes come from fat. The fat: protein: carb ratio will vary on an individual basis, as some people can tolerate more carbohydrates than others and remain in ketosis. There are also many different applications of the ketogenic diet that can be implemented such as a targeted keto (consuming carbohydrates only around a workout). In the clinical setting, fat intake of roughly 90% of total calories is common, but we now know that doesn’t necessarily need to be the case to acquire benefits, which is why it is crucial to individualize the approach. Outside of the amount of fat required, the amount of protein allowed each day that will keep someone in ketosis has been debated. There is a misconception that consuming too much protein will kick a person out of ketosis due to gluconeogenesis (creating glucose from non-carbohydrate foods thus releasing too much insulin to remain in ketosis), but we now know that that is not the case, especially with the emergence of the carnivore diet. The carnivore diet, a more extreme variation of the ketogenic diet in which an individual only consumes animal product, still allows people to remain in ketosis in spite of consuming hundreds of grams of protein per day. I would like to clarify as well that in general, it is the low carbohydrate intake that matters most, as that is what is going to elicit the switch from glucose as fuel to ketones, not how high you can jack your protein and fat up.
What is Ketosis?
Ketosis is a natural physiological condition that can occur in situations outside of just eating a low carbohydrate diet (which we will explore more in-depth later). For example, if you fast for long enough or if you don’t replenish after a glycogen depleting workout, you could technically be in ketosis. This differs, however, from nutritional ketosis, which is the overarching goal of adopting a ketogenic diet. When an individual achieves nutritional ketosis, they are utilizing ketones from fat for fuel as opposed to glucose from carbohydrates as the main fuel source.
The Keto Flu
Feeding off of the above-mentioned physiology of entering into ketosis, I would like to discuss the keto flu which is a common phenomenon experienced by people who are beginning the transition from glucose to ketones. No surprises here folks, the keto flu is exactly what it sounds like, you feel like you have the flu. While there are multiple reasons why this occurs, I want to point out two of the most notable and give some suggestions for how to avoid this:
You are losing electrolytes more readily due to decreased carb intake. When you begin the KD, you will start to excrete your electrolytes at a more rapid pace through urine. If you are not replenishing your electrolytes appropriately, you can feel side effects such as headaches, nausea, cramping, etc. I recommend adding extra salt to all meals, as well as purchasing either an electrolyte supplement or an exogenous ketone supplement in order to help alleviate this.
You are not consuming adequate calories. Often times people who switch to keto lose a lot of weight right off the bat because they are essentially eliminating an entire food group (carbs) as well as the initial loss in water weight. It is crucial that you up your fat intake and protein intake to an appropriate level to support your caloric needs or else you will experience extreme hanger along with headaches, nausea, interrupted sleep, brain fog etc.
Why adopt a Ketogenic Diet?
There are many reasons why an individual may want to explore a KD. For one, KD’s have been shown to improve lab values such as triglycerides, HDL, LDL, and total cholesterol as well as improve body composition. From a more subjective standpoint, the KD has been reported to improve mental acuity, suppress appetite due to the satiating effects of fat, and reduce inflammation due to the suppression of IGF-1 and insulin production. While research on the KD and physique athletes as well as predominantly anaerobic sports is currently lacking, there is literature supporting its use in endurance sports. Lastly, if you are an individual who is simply looking for ways to optimize overall health and quality of life, I encourage you to try out different nutrition protocols because you truly never know what will make you feel best if you don’t experiment.
Starting recommendations for those interested in beginning a KD
First and foremost, I do not recommend anyone to go from a Standard American Diet (SAD) straight into a KD. The shock to the body as well as the dietary adjustment needed would be too great and likely lead to inability to adhere. What I would suggest is taking a more moderate-low carb approach to start, and as you start to decrease carbs, you can increase your fat. As stated above, macronutrient distribution will vary on an individual basis, but typically people will need to consume <50g total carbohydrates a day to remain in a state of nutritional ketosis. I recommend keeping a moderate-high protein intake throughout the entire process as we know that high protein is associated with muscle gain, better recovery, and increased satiety.
How do you know you are in Ketosis?
While many people opt for using urine strips to test ketone levels, I find this to be an inadequate method as it does not indicate the ketones running through your body at a cellular level which is what we are after here. For that reason, I believe the gold standard method for determining ketosis on an objective scale is by way of serum blood test. There is not a specific value set to determine whether a person is in ketosis from serum blood test, as this range will vary from person to person, but typically the range of 0.5-3.0 mmol/L B-Hydroxybutyrate (BHB) will be telling. BHB is one of the three endogenous ketones (along with acetoacetate and acetone). While acetoacetate is actually the main ketone produced during ketogenesis in the liver, BHB is the most abundant during circulation and thus is the blood marker utilized. From a subjective standpoint, you will certainly know if you have entered ketosis based on mental acuity, suppressed appetite, no mid-day crash, etc. I personally went off of how I felt while I was following the ketogenic diet and never got blood serum BHB levels assessed.
In conclusion, the research supports the implementation of the KD as a safe dietary protocol with current uses in the clinical setting and implications for future practice. Based on my personal experience following a KD for ~4 months, as well as my research as a Dietetic Intern, I support those interested in trying the KD, but I encourage people to do so with the help of a coach or other healthcare professional. It is important to note that while the KD does have many benefits, some effects are still unclear such as the long-term impact on sports performance, particularly those that require fast-twitch muscle recruitment. As with anything nutrition related, proceed with caution and go into the experience open and patient.