Understanding The Brain’s Glucose Requirements…
Firstly, it is important to understand what energy sources the brain utilises, and how effectively it utilises them. Common knowledge is that the brain requires glucose to be readily available in the blood to be used as an energy source. The brain can also utilise the ketones produced during ketogenesis as a fuel source, and some fat-adapted individuals say they have improved cognitive function without carbohydrates. Having said that, the brain does require some carbohydrates to function correctly. There appears to be a common misconception in the dieting world where some assume that just because your body utilises glucose for a multitude of bodily functions, said substance should be heavily supplemented as part of a persons diet. In the case of glucose in the body, this is not required. The body, through gluconeogenesis in the liver, produces enough glucose for the body to survive effectively every day. Supplementing this production with lots of dietary carbohydrate derived glucose is not necessary and can promote insidious fat gain.
Getting a little bit more technical
The brain is no doubt an important organ, and so we should take care in providing it with a steady stream of energy. If the brain’s glucose levels are decreased too rapidly, a person can enter a state of hypoglycaemia . This is not good, and prolonged or sever hypoglycaemic states can even push a person into a coma. The brain is actually a well adapted organ, deriving (when on a fat adapted, low carbohydrate, high fat diet) most of its energy requirements from ketones and ketone production. This production usually takes place in the liver, but the brain has the capability of producing ketones itself. Generally speaking, ketones can account for up to 3/4 of the energy requirements of the brain. The remaining glucose requirements should come from dietary glucose intake, and will typically be around 30 grams of glucose if you are full blown ketogenic.
The Brain’s Energy Sources:
- Lactate: This is the by-product of glucose burning in the muscles of the body during exercise. The brain uses lactate as a primary source of energy while exercising, and will actually prefer to utilise lactate over glucose if it’s available. Lactate promotes better general brain operation anyway, so this is totally fine and in fact desirable. Have you ever heard how people say they feel much more responsive and alert? Well, lactate could be the source of this change…
- Glucose: Drawn from carbohydrates in foods, glucose is a fuel source often over supplemented and over provided to the body. Through gluconeogenesis however, the demands of the body on glucose for energy is effectively mitigated and reduced to what some may consider, very low levels. Gluconeogenesis, as discussed above, is where the liver converts amino acids into glucose for the body to use.
- Ketones: These are derived from ketosis, which is related to gluconeogenesis, and while ketones aren’t the only energy source used by the brain (just like glucose isnt), they form part of the complicated concoction our brains draw energy from.
As we can see, the brain’s energy demands aren’t straight forward. They require a mixture of chemicals and substances to draw energy from, and operate best when a balance is available. I have personal experience with operating in a state of ketosis, and I can honestly say that I have more focus, energy and ability to process cognitive challenges. I’d recommend anyone who had a good deal of control and interest in living the healthiest life they can to try ketosis and living as “cleanly” as possible.
I cover ketosis quite extensively in my new book “How To Paleo – Lose Weight, Build Muscle and Avoid Doctors”. It is to be released very soon, if you have subscribed, I’ll send out an email letting everyone one know when it’s available for purchase (and I’ll include a little something extra too). If you haven’t subscribed, please do so to receive updates on new posts and other great informative tips on living primal and embracing the paleo diet.