Dietary Fat: the Most Important Nutrient for an Athlete?

While the role of carbohydrates and protein in an endurance athlete's diet is clear, dietary fat is often overlooked. It's true that you should avoid fat before a race or intense training session, but a healthy consumption of fat is vital for your health.

In this blog, we explore the role of fat in your body, the types of dietary fat, and what fat you should include in your diet.

What's the role of fat in your body?

Fats have several important functions in your body – they are the building blocks of your cells, they regulate the metabolism, absorption, and transport of fat-soluble vitamins A, D, E, and K (learn more about the vital role of vitamin D), they are involved in hormone production, and they provide insulation.

Fats are also your body's main energy reserve, and they have one very distinct benefit – they taste good, contributing to the aroma and texture of your meals.

Types of fat and recommended intake

Dietary fat is mostly composed of glycerol and three fatty acids.

Fatty acids are divided based on their length (number of carbon atoms), number of double bonds, and the position of double bonds in the chain:

• saturated fatty acids have no double bonds,
• monounsaturated fatty acids contain a single double bond,
• polyunsaturated fatty acids contain two or more double bonds.

Healthy forms of fat can be found in numerous foods that you can include in your everyday diet.

The type of fatty acids determines the property of fat and how this fat influences your health.

The least beneficial for your body is saturated fat, found primarily in foods of animal origin, such as fatty meat, milk and dairy products, beef tallow, and lard. Saturated fat is also present in many foods of plant origin, such as coconut, palm, and cocoa butter. One thing all these sources of fat have in common is that at room temperature they are solids (e.g., a block of butter).

A high intake of these fats is related to an increased risk of cardiovascular disease, which is why it is recommended to limit the intake to maximum 10% of your daily energy intake or one third of all consumed fats.

Contrary to saturated fat, unsaturated fat has a positive influence on blood sugar levels (it reduces LDL cholesterol) and cardiovascular health. At room temperature, unsaturated fats are usually liquid (oil). It is recommended that they represent 20% of your daily energy intake or two thirds of all consumed fats.

Omega-6 and omega-3 fatty acids

Two fatty acids are essential: linoleic (omega-6) and α-linolenic acid (omega-3). This means that we need them to survive and must get them with food.

Omega-6 and omega-3 fatty acids are key for the proper functioning of the body, but they need to be present in the correct ratio. Both types of fatty acids in the body compete for the same enzymes, which transform them into biologically-active compounds.

If more omega-6 fatty acids are present in the body, the body will use proportionally more enzymes to transform them, which leads to inflammation. The recommended ratio for the intake of omega-6 and omega-3 fatty acids is 5:1. This means that omega-6 fatty acids should represent 2.5% and omega-3 fatty acids 0.5% of your daily energy intake.

Omega-6 and omega-3 fatty acids are often present together in foods. Many foods that are a good source of omega-3 are often an even richer source of omega-6. Consequently, the ratio of consumed omega-6 and omega-3 fatty acids for most people is much higher than 5:1, going as high as 20:1 and beyond. A classic example of such a food are walnuts. Walnuts contain lots of omega-3 fatty acids, but they are even richer with omega-6 fatty acids. The ratio is 4:1.

Trans fat

A special category of fats are trans fatty acids or trans fats. Trans fats contain at least one double bond in the trans configuration, while most unsaturated fatty acids have a double bond in the cis configuration.

We separate natural trans fats, which are present in meat and milk of ruminants as a consequence of microorganisms in their digestive tract, and industrial trans fats, which are produced in the process of hydrogenation of plant oils. The latter have beneficial technological properties, which makes them popular in the food industry. But they also have a negative aspect, that is they are harmful to your health. The intake of industrial trans fats is linked to an increased concentration of cholesterol in the blood, which leads to increased risk of cardiovascular diseases. Compared to saturated fatty acids, they have a significantly greater influence on the incidence of ateroschlerosis.

Looking at 10, 20, and 30% of the daily energy intake, it seems you have to consume a large quantity of fat. But keep in mind that one gram of fat (9 kcal or 38 kJ) contains more than double the amount of energy compared to one gram of protein or carbohydrates (4 kcal or 17 kJ). 

Type of fat	Food	Recommended % daily energy intake
Saturated	Fatty cuts of meat (e.g., neck, fatty meat, thighs with skin), full-fat dairy products (butter, cream, cheese, ice cream), lard, coconut oil, cocoa butter	up to 10%
Unsaturated	Rapeseed oil, olive oil, sesame, nuts and nut oils (peanuts, almonds, hazelnuts), avocado	20%
Omega-3	Fatty fish (salmon, mackerel, herring, trout), rapeseed oil, linseed and linseed oil	0.5%
Omega-6	Sunflower oil, maize oil, soy oil, safflower oil	2.5%
Trans	Hydrogenated fat and oil and related products (pastry, biscuits, puff pastry), milk and ruminant meat	up to 1%

Examples of meals that are a source of unsaturated fatty acids

BREAKFAST:

• Oatmeal with linseed and Greek yogurt
• Toast with avocado and smoked salmon
• Rye bread with peanut butter and jam

LUNCH:

• Pasta with sardine sauce
• Risotto with salmon
• Mackerel with potatoes and chard

DINNER:

• Salat with buckwheat porridge, eggs, and cold-pressed oil
• Egg omelet with veggies and sesame
• Rice noodles with veggies, chicken, and nuts

Conclusion

Although dietary fats do not provide a fast source of energy and may burden the digestive tract before, during, and after physical activity, they are essential for your health.

Limiting the intake of fat below 20% of the daily energy intake should be reserved for special scenarios, such as before race or intense training session when filling up your glycogen stores. Prolonged restriction of your fat intake below the recommended threshold may lead to vitamin A, D, E, and K deficiency and to hormonal problems, which may result in unwanted health complications.

But it's not just about the amount of fat you consume, the type is also important. Unsaturated fat has the upper hand, and it can be found in foods of plant origin and fish oil, while the intake of saturated fat should be limited to up to 10% of your daily energy intake.