Welcome to Part 3 of our series on Keto and CrossFit. In case you missed it, Part 1 covered the background on keto, whether it could work alongside CrossFit and some keto and CrossFit studies. In Part 2, we explored how keto affects strength, gymnastics, Olympic weightlifting and endurance in athletes, all key components in CrossFit.
So far we have explained how, compared to a traditional diet, keto can result in much better body composition, lean mass maintenance or gain, no loss in performance, a better hormonal profile, and the ability to create glucose from protein, fat and lactate very efficiently via a process called Gluconeogenesis.
In this article, we are going to look at the impact of indirect measures that keto has for an athlete. The things that happen outside the Box but can still have a huge impact on overall performance and well-being.
Overall, we’ll detail why keto can improve metabolic efficiency and cover the “magic” effects of ketones (BHB and acetoacetate) on inflammation, oxidative damage, mental health and even sleep.
Keto and Energy Metabolism
Many metabolic changes begin to occur when you become a fat burning machine via nutritional ketosis. These changes result in metabolic flexibility, in which an individual is able to burn both fat and carbs for energy efficiently to attain optimal health and athleticism.
Energy Metabolism Study #1: Insulin, ketone bodies, and mitochondrial energy transduction
This study was done in rats, so we can’t and won’t draw too many conclusions from it, but it does demonstrate that the addition of ketones to insulin and glucose results in a 36% increase in efficiency of the working rat heart.
This means the amount of energy created from the oxygen consumed increased, making the heart work more efficiently. The study finds that the ketones and insulin seem to make the mitochondria work more efficiently.
Getting more work out of the heart with less energy demand is a big win in my books.
Energy Metabolism Study #2: Metabolic Effects of the Very-Low-Carbohydrate Diets: Misunderstood “Villains” of Human Metabolism
This study results in many interesting claims and findings, but we will just focus on a couple. First, let’s look at the energy produced from glucose versus the energy produced from ketones:
- 100 grams of glucose creates 8.7 kg of ATP (adenosine triphosphate, the energy molecule) whereas 100 grams of the ketone BHB yields 10.5 kg of ATP.
Thus, BHB is a more efficient energy source than glucose on a gram for gram basis.
Another interesting note is that:
- when ketones are present in the blood, even with glucose, the brain will actually prefer to use the ketones over the glucose. Thus, ketones are the preferred fuel of the brain, not glucose.
Quoting the study, this is what the scientists found regarding the creation of energy (ATP):
“It has also been claimed that carbohydrate provides the only macronutrient substrate whose stored energy generates ATP non-aerobically. This is not the case, however, since several studies have shown that amino acid catabolism also provides a source of anaerobic energy production.”
This might be news to most people reading this article, but the traditional viewpoint is that only glucose produces ATP without the input of oxygen (non-aerobically). As exercise gets more intense, the body uses the non-aerobic metabolism more and more.
The fact that amino acids can contribute to this form of metabolism means we don’t need to rely 100% on carbohydrates for ATP production (without the input of oxygen) for high intensity exercise. This is pretty revolutionary, and warrants further investigation.
Energy Metabolism Study #3: Novel ketone diet enhances physical and cognitive performance.
The start of the study reads:
“Ketone bodies are the most energy-efficient fuel and yield more ATP per mole of substrate than pyruvate and increase the free energy released from ATP hydrolysis…Ketones may also be beneficial for muscle and brain in times of stress, such as endurance exercise.”
This study compared rats fed a carbohydrate-based diet vs a high exogenous ketone (ketone supplement) based diet. They found that rats on the high ketone diet could run 32% further on the treadmill and solved a maze 38% faster than the control diet.
The scientists found that “the novel ketone diet, therefore, improved physical performance and cognitive function in rats, and its energy-sparing properties suggest that it may help to treat a range of human conditions with metabolic abnormalities.”
By using ketones as fuel, you are using the most energy-efficient fuel on the planet, improving neural health, and can benefit muscle and brain during times of high stress (for example a WOD).
Energy Metabolism Study #4: Nutritional Ketosis Alters Fuel Preference and Thereby Endurance Performance in Athletes
For this study, 39 high-performance athletes were given a supplemental ketone ester-based drink to determine the effects on physical performance and fuel selection preference.
“We show how this unique metabolic state improves physical endurance by altering fuel competition for oxidative respiration. Ketosis decreased muscle glycolysis and plasma lactate concentrations, while providing an alternative substrate for oxidative phosphorylation. Ketosis increased intramuscular triacylglycerol oxidation during exercise, even in the presence of normal muscle glycogen, co-ingested carbohydrate and elevated insulin.”
In English, ketones resulted in an improvement in physical endurance by reducing the need for glucose and reducing the build-up of lactate (commonly thought of as that muscle burn during intense exercise). It is possible the lactate was being shuttled to the liver for gluconeogenesis, as we spoke about in the last post.
The body relied more on fat, including fat within the muscle, to fuel exercise, and less on the limited stores of glycogen. The scientists’ concluded: “These findings may hold clues to greater human potential and a better understanding of fuel metabolism in health and disease.”
It’s important to note, however, that these biochemical advantages of ketosis in humans were found using a ketone ester-based form of nutrition instead of placing the athletes on a caloric or carbohydrate restriction to produce ketones.
Performing at a high level, but still sparing muscle glycogen means that the athlete will have more fuel in the tank for the highest energy outputs. Decreased lactate may also mean less of that muscle burn, and the athlete may potentially be able to exercise a little longer.
The increase of fat usage within the muscle also contributes to glycogen sparing (the use of non-carbohydrates as a source of energy during exercise so that the depletion of muscle glycogen stores is delayed), and could be very beneficial. This would mean there is more glucose in the tank for those harder efforts.
Another important part of recovery is inflammation or oxidative damage. Find out how the ketogenic diet affects these parameters…