Fat: Sore Subject around the holidays

Lorenzo Wimmer

November 18, 2016

fats healthy fats holidays

What are fats?

Fats are macronutrients in our diet that we consume in large quantities that gives us energy to survive and compete. Without them, we would only carry about enough energy stored in the form of glycogen in our muscles and liver for about 90 minutes to 2 hours of intense exercise. (Muscle glycogen comprises about 400g of glycogen, whereas liver glycogen comprises about 100g) Once we have expended our liver and muscle glycogen, the body must convert stored fat to energy. Let’s go back to last months’ article about the energy contained in fat versus carbohydrate and protein. Remember that fats contain about 9 cal of energy per gram, whereas carbohydrates and proteins contain about 4 calories per gram.

The preferred fuel

As endurance athletes, we all run primarily on glucose… for the first 90 minutes at least. Beyond that, our body must convert fats to energy. How does it do that?

Imagine if you will, our bodies to only survive on glucose from the glycogen stored in our muscles and liver. We wouldn’t last very long in the wild (or on the trail) if that small amount of stored carbohydrates was all that we relied upon to survive.

Predominantly humans rely upon fats, ketones, and a minimal amount of glucose (from gluconeogenesis) that got us to where we are today. Ketones, or ketone bodies are fragments of fats and proteins that the body can burn very efficiently as an alternative fuel. The heart muscle loves to run very efficiently on ketones. The brain however, prefers glucose, and the body can make enough glucose for the brain, red blood cells and kidneys to function quite nicely with leftovers of combustion such as lactate, pyruvate and amino acids. An endurance athlete with 10% of body fat still has at least 60,000 calories of energy left in their body, enough to complete at least a full Ironman.

Survival Mode:

Fats are essential in our diet, but which fats? Our ability to store and utilize fat as fuel is a testament of how we still exist on earth today. Imagine for a moment, since most of you live in the mountains and it is snowing, and you cannot get out of your cave to go hunt (at Safeway or the forest) for three or four days. Remember we only store enough energy in the form of glycogen to get us through about 90 to 120 minutes of exercise, which includes breathing at altitude. Hence, unless trained otherwise, our bodies are always set in survival mode. We’re always storing for a rainy/snowy day that we cannot go hunt and gather food to eat; so we store excess foods we consume in the form fat. Why? It’s more efficient for the body to do so. Fat does not require water to be stored, transported or utilized. Glycogen/glucose does. In doing so, it requires about 30% more weight in water to cart around if we only relied upon glucose as our backup fuel source.

Since our body is continually in a survival mode, it must be trained to understand that it is OK to burn stored fat, that we are not going to starve anytime soon. This should be the goal for most endurance athletes, to train your bodies to burn fat by reducing your intake of carbohydrates, lowering your insulin response and become insulin sensitive. The less work your pancreas has to do, the more efficiently your machine will run. This is a good example of using fats as an endurance fuel, rather than sugars, such as energy gels. Less GI distress, more energy per gram.

Good fats/bad fats… they are not all created equal.

So fats, as molecules contain three fatty acids each. They can either be saturated, mono unsaturated or poly unsaturated fatty acids. But what is this “saturated” stuff?

Every newscast, every commercial is talking about saturated fat, but not one of them has taken the time to tell you what saturated means. It is merely a chemical definition, and it is the number of double bonds in the molecule. It is also counterintuitive, as saturated fatty acid’s contain no double bonds, mono unsaturated fatty acid’s have one double bond and poly unsaturated fatty acid’s have two or more double bonds. So you can see, “saturated” has nothing to do with being saturated with fat.

How can you tell the difference? Fats that are mostly saturated, like butter, tend to be solid, where as mostly unsaturated fats like olive oil are liquid at room temperature.

Omega-3 vs. Omega-6 fats

Good fats in our diet, like most things good for us requires a balance. A balance of Omega-3 to Omega-6 fats should be at least 3:1. We already consume more than our share of omega six fats, from processed foods, french fries and the like. The omega-3 fats, found in avocados, egg yolks and some plants and vegetables like Purslane, are a wealth of fats for omnivores and vegetarians alike. Oils such as canola or corn oil, should be avoided as much as possible, preferring oils such as avocado oil or coconut oil instead. Canola oil by the way, is an acronym, coming from Canadian Oil Low Acid. It is not “naturally” occurring, as it is produced using high heat and solvents to render the oil from the rapeseed palatable.

Change, same as in everything else…

It doesn’t happen overnight. Changing your body to becoming fat adapted from a carbohydrate burning engine will take some time and patience. Since we are all very different in body make up, metabolism, ages and food preferences, each path you take maybe a little different. The destination should all be about the same, very rewarding in your endurance endeavors, allowing your body to burn thousands of calories of stored energy in the form of fat, where ever you may carry it. In general terms, a timeframe of 10 days to two weeks is not uncommon. You do not necessarily have to become keto adapted, but you do have to eat foods containing the right types of fats. Try to avoid any food that advertises that it is fat free. The flavor has to come from somewhere, and that somewhere is most likely carbohydrates. Your choices in milk should be whole milk versus non-fat. Remember we are trying to give our poor little pancreas a rest, and the fewer carbohydrates you ingest means it has less work to do and less extra carbohydrates that it will convert to fat in your liver if you consume more than you immediately need. The more insulin sensitive you become, the more efficient your machine will run with the fat stores you have, and less metabolic stress on your body for the long run.


Thanks again for listening. Any questions, please pass them along. Have a great snowy holiday season, and I hope to see many of you before the year’s end, somewhere on the trail.