When our bodies are in starvation, as in the famines of our ancestors, our bodies run out of stored glucose and we need to start using our fat stores and muscle for energy. When we break down fat in the absence of glucose, our bodies create ketones. The main ketones that we make are beta-hydroxybutyrate and acetoacetate.
Our brains function very well on ketones. In starvation, up to 2/3rds of your brain’s energy comes in the form of ketones. The rest comes from production of glucose from your muscle proteins. Fortunately for us, ketones are muscle sparing energy for the brain which can burn up to 600 Calories per day! (Some more than others LOL).
Ketones also signal to your cells to turn on fat burning machinery and anti-oxidant mechanisms to protect the cells from damage. Some might call this an anti-aging mechanism. Oxidative protein and cellular damage is thought to lead to aging, heart disease, and cancer. Furthermore ketones produce much less free radical oxidative molecules when used as fuel compared to carbohydrate.
Because the typical American diet is so flush with carbohydrate calories, we never see enough depletion in glycogen to require the production of ketones. Constant elevations in insulin from carbohydrate feeding shut down fat mobilization and conversion to ketones. We see a small rise in ketone production after an overnight fast or after prolonged glycogen depleting exercise without necessarily starving, but the rise is quite small and short lived. We try to take advantage of this fat burning mechanism with the intermittent fasting and fasted cardio techniques we will discuss in further blog posts.
Very low carbohydrate diets (with higher fat and moderate protein) that raise ketone levels have been shown to improve many markers of health. They reduce blood triglycerides and LDL cholesterol potentially reducing the risk of heart disease. They improve body composition burning fat and maintaining lean mass. They improve insulin sensitivity with curative effects on type 2 diabetes. They decrease blood pressure and inflammation in the body. Compared to low-fat diets (with higher carbohydrate), low carbohydrate diets appear to be much more effective in improving markers of cardiovascular health.
Beyond promoting cardiovascular health, ketones also protect the brain and improve energetics of endurance exercise. As for the brain, multiple studies have shown the benefit of nutritional ketosis on migraines, Alzheimer’s Disease, seizure disorders, Parkinson’s, autism, and brain trauma. With regards to exercise, in a low-carb ketogenic state your muscle learns to handle fats better. Your muscle makes more fat burning machinery and more proteins for protection against oxidative damage. Furthermore, by becoming adapted to ketones, there is less dependence on glucose stores for energy production. Thus, when completely glycogen depleted, your keto-adapted muscle won’t “hit the wall” or “bonk” when glucose is no longer available.
Dr. Jeff Volek at presented data at the 2014 ISSN Annual Meeting demonstrating that keto-adapted endurance athletes are metabolically superior in burning fat for energy. They are “bonk proof” and show no evidence of performance decrement without the typical carb load.
Ketosis is a rise in blood ketones greater than 0.5mmol/L. Nutritional ketosis is considered to occur between 0.5mmol/L and 3-5mmol/L. In order to get ketone levels this high, one must either be in starvation, or carbohydrate depleted. The majority of people will be in ketosis (a ketogenic state) with carbohydrate intakes below 50g per day. Some very resistant individuals may need to go as low as 30g/day but others may just have to go below 100g/d. This amount of carbohydrate is essentially the amount of carbs one would see with consuming fibrous green vegetables with each meal. In other words, there would be no consumption of any added starches or sugars. Small quantities of sugars could potentially be consumed in the form of fibrous fruits or berries.
Here is an example of foods in a ketogenic diet with less than 50g of carbohydrate per day.
Meal 1: Spinach, egg whites, Swiss cheese, and Canadian bacon
Meal 2: Whey protein shake and natural peanut butter
Meal 3: Salmon, Broccoli, and Lettuce with oil and vinegar
Meal 4: Cottage cheese cinnamon and a few blueberries
Meal 5: Sirloin Steak with cheddar cheese mashed cauliflower, asparagus,
--sugar free gelatin dessert J
Doesn’t sound too bad to me! It is always a challenge to try something new. Learn about the carbohydrate content of the foods you eat. Consider trying ketone urine dipsticks to check if you are in ketosis. If this doesn’t seem to be working consider a blood test for ketones, as the urine test is less accurate.
If you are at a plateau in your goal to getting lean, try a ketogenic diet. I think you will be amazed at the results.