Fat adapted endurance athletes – A matter of future

Fat adapted athletes around the globe keep achieving remarkable results. Nutrition is crucial for top results in any endurance sports. Although the main source for energy for endurance athletes for decades have been the carbohydrates, things are rapidly changing. In the past 10 years, more and more endurance athletes are adopting the Low-Carb High-Fat approach to nutrition and they are achieving excellent results in energy utilisation and performance. Many studies are supporting the theory that our body manages the energy sources from stored fat and dietary fat much more efficiently than if we depend on glucose as fuel. 

Having the best nutrition tactic for fat adapted athletes

Nutrition tactics play an essential role in our quest to train and perform the best we can! It can strategically help us to optimise practice adaptation, and at the same time, boost our recovery. Of course, a proper nutrition plan is helping us reach full potential during our athletic career. 

For decades, and I could say throughout the history of endurance sports, athletes have been dependant on glucose, and therefore glycogen refuelling. However, In recent years, more and more endurance athletes are turning to a bold new approach to nutrition and lifestyle. Have you heard about the term Fat adapted athletes? 

Fat adaptation could be called a metabolic reorganisation from the glucose as the primal fuel source to a predominant fuel source of fat. This stands for both body fat and the fat we consume through food. This metabolic state, when the body reaches for fat as a primary energy source is not new to humans. In fact, during the dawn of mankind, humans utilised this system due to the lack of sugar and carbohydrates in their environment. 

This is the normal, metabolic state for us because we are usually being born in ketosis. Before the food pyramids based on cereals and carbohydrates created larger numbers of obesity, humans were in a continuous yearly period of fat adaption. 

What means fat adaptation for the endurance athletes?

Fat adaptation means you can efficiently burn deposited fat for energy throughout the race. Regardless of your body fat composition, large amounts of energy are always available to you from your body fat. Even the slimmest person who scales, for example, 60kg with 9% body fat, has 6kg of fat up to them. As we know, a gram of fat gives us 9 calories which leads to 54,000 available to an athlete at any point of the race.

For athletes, fat adaptation simply means they can rely further on fat for energy during the performance. This then creates a glycogen saving impact. This means that glycogen stored in the muscle is available to assist high-intensity performance (where it is needed).

For endurance athletes, this comes as a great relief! If you are a well-trained athlete with 2000 calories of muscle glycogen stored, and your main fuel is sugar, this means you burn 1000 calories/hour. Obviously, you will run out of your main fuel after 2 hours. Even if you were able to consume 300 calories per hour, you will still need 700 calories more to endure 2 hours. 

This is well known to endurance athletes as hitting the wall. If you are an endurance athlete whose energy just gets lower and slower in a marathon or ultramarathon crucial phase, working on fat adaptation can help you to essentially never run out of fuel.

How can you become a fat adapted athlete?

There are two primary approaches for perfect fat adaptation:

Lowering carbohydrates with a higher fat intake is the basic principle. This is especially helpful to improve fat adaptation, as it reduces your sugar burning metabolism. This approach also gives you five or more hours between meals with stabilisation of blood glucose and energy utilisation.  Furthermore, Low-carb intake is teaching your body to have the fat as main fuel during the training or race. What’s interesting, this metabolic state will preserve your glycogen so you can rely on it in periods of high intensity. A very comprehensive guide is recommending a total intake of 10% carbohydrates, 20% protein, and 70% good fats in your daily meals.

The second approach or strategy which can be implemented together with the diet is so-called fasted training. If an athlete performs this kind of training during the ‘off-season’ for 8 to 12 weeks, this improves their fat utilisation and minimises the dependence on exogenous fuel sources (such as energy drinks, bars or gels). 

It would be ideal to start with lower intensity sessions of 60-90 minutes in duration. As your fat adaptation improves, continuously extend this to two or three hours. 

Fat as an excellent fuel

Commonly, runners’ bodies utilise fuel saved in the form of glycogen, which is simply and instantly metabolised. This involves essentially burning carbohydrates. On the other side, what if we think of fat as the body’s emergency fuel? Somehow we always store fat and don’t utilise it until we are completely depleted of carbohydrates. 

What science has to say about it?

Professor in School for human movement Science Dr Lize Havemann-Nel of North-West University in South Africa states that through a period of  five days of consuming a higher percentage of fat and a lower percentage of carbs, “the body retools itself to use fat extra efficiently through the activity with the intention to save muscle glycogen.”

 Professor Havemann-Nel put endurance athletes through individual time-trial studies to observe the effects of several high fat/low carb days accompanied by one or two days of carbohydrate loading. The results were interesting. Even on the days of higher carb consumption, athletes burned fat for fuel. 

Our bodies can store much more fat calories than carb calories, approximately 20 times more. So, if you can store and burn calories from fat, that means increased levels of energy stores when race time comes. This also means less need for refuelling during the race.

The ketogenic diet practices the same idea, but it also goes one step further. It works by drastically decreasing carbohydrate consumption. This is resulting in increased ketones which are molecules created by the liver when fat is oxidised. Some research shows that a significantly higher ketone level can improve performance for endurance athletes like ultra-runners. This is also known as Keto-adaptation. 

Optimal nutrition for fat adaptation

Balancing intake with output to achieve maximum performance for fat adapted athletes is quite different from the glucose burner athletes. Basically, you are turning the nutrition pyramid upside-down and exclude all grains, starches and sugars. The diet still contains lots of nutritious vegetables and fruits that have a low glycemic index. You are choosing fatty parts of meat and fish because fat is best metabolised when comes in its natural form with the protein. For example, you will no longer eat chicken breast but opt for legs and wings. 

On the other side, the best protein to fat ratio when it comes to ease of digestion comes from lamb and goat. Veal is also a great choice for fat adapted athletes because it’s easier to digest than beef, however, beef provides more nutrients. 

With seafood and fish, you have to be careful because they always come with a larger amount of protein than fat. The solution here is in adding healthy fats from butter, coconut oil, olive oil and avocado oil. 

A great thing about fat adapted athletes is that they can consume homemade fat-bombs which usually consist of dairy or nut-based butter and cacao powder with stevia or monk fruit. This fat bombs also have a psychological impact because they taste and feel like chocolate and they can be taken as fat-intake boosters or even for refuelling during the race.