The Ketogenic Diet: Common Questions Answered
Authors: Sarah M. Rice, Douglas B. Reynolds
Introduction
This series was compiled as an attempt to address common concerns about the ketogenic diet as expressed on many popular social media platforms by the lay public. Confusion around the ketogenic diet abounds in the media and on the internet, making it difficult for everyone. Lack of nuance around personalization and diet quality issues can detract from the fact that more and more healthcare providers are successfully implementing ketogenic or carbohydrate-reduced diets to help people
improve their health.
The content is streamlined for accessibility, and every effort has been made to ensure that the information is accurate, devoid of hyperbole and dogma, and supported by the literature. Over 300 references are supplied to enable further reading, and curious clinicians can use these as a springboard for further research. Resources are also listed at the end of the document, which refer to books and websites that expand on this content.
What is a Ketogenic Diet?
A well-formulated ketogenic diet includes adequate energy, protein, fat, vitamins, and minerals. The ketogenic diet may be defined by an absolute amount of carbohydrates per day (grams/day):
- Very low-carbohydrate ketogenic (VLCK) diets recommend < 30g of dietary carbohydrate per day.1
- Low-carbohydrate ketogenic (LCK) diets recommend < 50 g of dietary carbohydrate per day.2
- Therapeutic ketogenic diets involve a more focused approach in obtaining therapeutic levels of ketones, which may be required for certain conditions like epilepsy, neurological disorders, supporting cancer treatment, and mental health conditions. Dietary carbohydrate intake is < 50g/day, often in the lower end of the range. Adjustments may be required to facilitate target ketone levels, and an experienced practitioner may be required to guide the process.3
Limiting carbohydrates to 20 to 50 grams per day enables the body to enter a state of nutritional ketosis. When carbohydrate levels are very low, the hormone profile begins to mimic that of a fasted state (low insulin levels) which promotes the breakdown of fat stores (lipolysis) releasing fatty acids into circulation. These fatty acids are metabolized to ketone bodies (ketones) by the liver and secreted as an alternative fuel source—this is in addition to glucose manufactured by the liver via a process known as gluconeogenesis. Therefore, the body is able to generate sufficient fuel to fulfill its energy requirements.4 Some individuals find it more difficult to enter ketosis; if that is your goal, you may need to consume carbohydrates on the lower end of the spectrum.
Ketone bodies are readily utilized by the heart, brain, and muscle tissues, and they have various benefits for neurological functions, cellular longevity, metabolic balance, and cardiovascular health.5
Some conditions benefit from higher levels of ketone bodies for therapeutic benefit and this type of ketogenic diet may be referred to as medical ketogenic therapy or similar. This can require adjustments to the macronutrient ratios and the measurement of ketones to ensure a therapeutic effect is reached. Conditions such as epilepsy, neurological disorders, and mental health diagnoses are more likely to require this approach with subsequent monitoring and adjustments to ensure the best outcomes.3 At the same time, you may be able to achieve your health goals using a less significant level of carbohydrate reduction. This is where a personalized approach is important.
One variation of the low-carbohydrate, high-fat ketogenic diet is a zero-carbohydrate (also known as carnivore) approach. While this may seem extreme, there are a subset of individuals who are succeeding with this approach, particularly with regard to autoimmune,6,7 inflammatory,7,8 gastrointestinal,7,9 and mental health conditions.10–12 These conditions may be triggered by sensitivities to plant matter, and in these instances, a zero carbohydrate approach serves as an exclusion protocol, allowing the body to heal.9,12,13 From a place of healing, there may be scope to introduce a wider range of foods which could include plants if desired. Anecdotally, some individuals report that they are unable to broaden their diet beyond animal-based meat products and remain happy with their health status, choosing to continue this approach. Though there may be concerns about nutritional sufficiency, this problem has not been reported in the available literature, and data suggest it may not be a problem based on six-month reports,10 ancestral dietary patterns,12,13 and critical reviews.12,14 As with any therapeutic intervention, tracking biometrics is advised to ensure health goals are being met and nutritional sufficiency is achieved.15
Another aspect influencing the decision to maintain this approach is its simplicity and ease in terms of shopping and cooking.10 Removing decision making around food may be helpful for some people and enable better adherence to a reduced carbohydrate diet. Personal experimentation is a common theme when individuals have adopted a zero-carbohydrate approach, logging physical and emotional responses to foods and adjusting food intake accordingly.10,11 Formal studies on a zero-carbohydrate approach are currently limited to qualitative surveys and case studies, so a considered approach, monitoring health markers over time, is recommended.
The ketogenic diet is often referred to as ‘keto’ in the media. It is worth considering that this is a broad term and that diet quality and approach should be measured against standardized terms to ensure the best chance of achieving the desired health outcomes. Different versions of the ketogenic diet have come into existence in order to help people achieve their health goals. While this might seem confusing, it can be viewed as a personalized approach where the level of carbohydrate reduction is tailored to individual needs.
Common Symptoms During Adaptation and “Keto-Flu”
“Keto flu” is a term used in the media to describe common symptoms that may be experienced during adaptation to a ketogenic diet. They are usually mild and transitory and often resolve in a few days. Symptoms may include fatigue, headache, muscle cramps, mild constipation, and light-headedness. The main mechanism behind these effects is that a reduction in carbohydrates alters signaling pathways that cause the body to hold on to water and sodium. Lower carbohydrate intakes cause the body to use up glycogen stores and insulin levels fall. Both these mechanisms have a diuretic effect whereby excess fluid (and with it, sodium) are excreted by the body. An effective remedy is to increase fluid intake with the addition of 1–1.5 teaspoons (5–7g) of salt (2–3 g sodium) daily. This can be consumed via bone broth or bouillon.12,16 Some individuals may benefit from additional salt on an ongoing basis; a personalized approach is important.
Muscular symptoms can be supported by adding elemental magnesium (200–400 mg/day) to the fluid and salt routine suggested above. Rarely, potassium intake may also be a consideration where there are muscular symptoms, though ensuring sufficient salt intake usually prevents this. Potassium is generally obtained in sufficient quantities through vegetables and bone broth (low-salt with 50% potassium may also be used if needed).2 Ongoing symptoms require clinical assessment and review of nutritional intake and further testing. Fortunately, most individuals find the adaptation stage passes quickly (7–10 days), and for others, there may be no or minimal symptoms for just a few days.12
It is important to consult with a medical professional before embarking on a ketogenic diet if you are taking any medications. In particular, individuals taking medication for diabetes, hypertension, and psychiatric disorders need to be monitored as medications may need rapid adjustments. If you have an unstable medical condition you may not be suitable for this approach, or require close monitoring. Absolute contraindications are few and are primarily where there are disorders of metabolism such as carnitine deficiencies, polyphoria, beta oxidation disorders, and pyruvate carboxylase deficiency.
Overall, symptoms during adaptation pass quickly and benefits become noticeable. If symptoms persist it may reflect vitamin or nutritional deficiencies, or changes in a medical condition requiring the guidance of an experienced medical professional.
Ketogenic Diet Series
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