From Jeff Volek PhD and Dr Stephen Phinney MD’s book, The Art and Science of Low Carbohydrate Living, we read,
“The brain is the spoiled child of the organ family. It can burn glucose or ketones (or a combination of the two) and it can’t burn fat. This is interesting because the brain itself contains a lot of fatty acids in all its membranes and myelin (although little or none as triglycerides), and the many types of brain cells all contain mitochondria that should be capable of oxidizing fatty acids. Another surprise about the brain is how much energy it consumes each day (600 kcal) despite weighing just 3 pounds. This is more than 10-times the average energy use per pound of the rest of the body, which explains why the brain has such a large blood supply (to provide fuel and oxygen and also to keep it cool).
The other important fact about the brain’s fuel supply is that it contains no reserve supply of glycogen, and because it can’t burn fat, it is absolutely dependent upon a minute-by-minute blood supply containing both fuel and oxygen to meet its needs. This
Blood lactate testing for speed athletes; sprinters to endurance, has been used successfully for at least the last 20 years.
However, there is not much written about it for an athlete on a ketogenic low-carb diet.
This article will attempt to answer some questions and lay a framework for a ketogenic low-carb athlete to consider using blood lactate to improve performance through proper training of the two main energy fuel systems.
According to a Canadian study consuming caffeine can accelerate fat burning by acting as a ketogenic agent. The study found that ingesting 2.5 mg of caffeine per kilogram (1.14 mg per pound) of body weight increase ketone bodies by 88%. By ingesting twice the amount, or 5.0 mg/kg (2.27 mg/pound), can increase ketone bodies by 116%.
The Study’s Abstract
Brain glucose uptake declines during aging and is significantly impaired in Alzheimer’s disease. Ketones are the main alternative brain fuel to glucose so they represent a potential approach to compensate for the brain glucose reduction. Caffeine is of interest as a potential ketogenic agent owing to its actions on lipolysis/ lipid oxidation but whether it is ketogenic in humans is unknown. This study aimed to evaluate the acute ketogenic effect of two doses of caffeine in healthy adults (2.5; 5.0 mg/kg) during a 4-hour metabolic study period. Caffeine given at breakfast significantly stimulated ketone production in a dose dependent manner (+88%; +116%) and also raised plasma free fatty acids. Whether caffeine has longterm ketogenic effects or could enhance the ketogenic effect of medium chain triglycerides remains to be determined.
The peer reviewed study found here.
Why is this important?
The brain is dependent on glucose and can not use free fatty acids (FFA) for fuel like other organs and muscles. Thus, in the absence of glucose, the brain can only use
Seems like an easy answer. “I put food in my mouth and don’t think about it.” Let’s explore the science after you “don’t think about it” anymore.
Most of the time when you eat you ingest more food energy than you can immediately use. The excess energy needs to be stored for later use. The key to “storage for later use” or “immediate use” is insulin (and you thought insulin was something diabetics worried about).
Insulin is released into the blood stream when you eat carbohydrates and protein and to a very small amount when you eat fat. Insulin is a pathway key that does one of two things and in this order, 1) it turns on the storage of the excess as fat and 2) it keeps the cell’s glucose (the sugar that is made primarily from carbohydrates) receptors open so the