The ketogenic diet has been around for about 100 years. It was originally prescribed to treat refractory epilepsy in children. Awareness of the diet grew through an education campaign initiated by Hollywood movie producer, Jim Abrahams, after the diet cured his son’s epilepsy (read the story here).
According to The Charlie Foundation, ketogenic therapies are being used for autism, Alzheimer’s, brain tumor/cancer, Lou Gerhig's disease, mitochondrial disorders, Parkinson's disease and traumatic brain injury.
What Is a Ketogenic Diet?
According to the National Academies, the Acceptable Macronutrient Distribution Range is 45-65% carbohydrate, 10-35% protein, and 20-35% fat. In contrast, a ketogenic diet contains very little (5-10%) carbohydrate, adequate protein (0.8-1.0 g/kg body weight; 15-25%) and 70-85% fat. Yes, that is a lot of fat.
How does a ketogenic Diet work?
The ketogenic diet mimics fasting. In the absence of adequate carbohydrate, the liver is forced to burn fat to produce ketone bodies (e.g., acetoacetate, β-hydroxybutyrate). After the adaptation period, the body (including the brain) is able to use ketones for energy instead of glucose. Meanwhile, ketones suppress appetite and inhibit the breakdown of muscle mass.
The ketogenic diet is currently gaining traction in the ultra-endurance community. When the body is able to burn ketones for fuel, there is no fear of running out of carbohydrate (e.g., glucose, glycogen) and “hitting the wall.”
Following a high-fat, low-carb diet may also be therapeutic for people with insulin resistance and/or type 2 diabetes. According to this review article from the European Journal of Clinical Nutrition, "When dietary carbohydrate is restricted to a level below which it is not significantly converted to fat (a threshold that varies from person to person), signs and symptoms of insulin resistance improve or often disappear completely."
Ketosis vs. Ketoacidosis – Concentration Matters
The level of ketones is important to understand. Any time we fast (e.g., overnight), the body naturally begins to make ketones.
- Prolonged fasting (i.e., weeks) will result in ketone levels around 5 to 7 mmol/L.
- For a healthy human body, following a ketogenic diet will result in a state of ketosis, where ketone levels stay between 0.5 and 3.0 mmol/L.
- In contrast, ketoacidosis is when ketone levels increase ten-fold to 10 to 20+ mmol/L, usually due to insulin insufficiency (e.g., type 1 diabetes).
Risk of Heart Disease
Some people worry that eating copious amounts of fat will increase their risk for developing heart disease. The truth is, eating more fat may, or may not, increase your cholesterol. Read more here (link coming soon!).
Some studies show that a low-carbohydrate diet lowers atherogenicity, while others provide evidence for the opposite. There is a genetic component that confounds most studies. For example, folks who have a polymorphism in the PPAR gene may be less able to convert fat into ketones and, therefore, should not follow a ketogenic diet.
Additionally, high LDL cholesterol may not be as bad as we originally thought. The "large, buoyant" variety of LDL is much less problematic than the “small, dense" type). Read more here.
For a full list of contraindications, click here.
Written by Adair Lindsay with the assistance of Hannah Berkon