Despite the misinformation of the benefits for large amounts of fat (intake 30% or more of total calories from fats) in the literature of the recent date, it should be emphasized that fats have a high concentration of energy that does NOT lead to the improvement of sports results, body structure or physical weight when consumed in large quantities. With adults, AMDR for intake of fats is 20% – 30% of total calories. There are no relevant scientific information suggesting that the intake of fats above 25% of the total calories is generally useful for athletes. However, for athletes who are having difficulty in maintaining their body weight due to consumption of large amounts of energy (such as ski racing) or who have to withstand heavy loads (as is the case in American football), it may be necessary to take a higher amount of fats ( up to 35% AMDR limit). The few Americans who bring in less than 35% of the total calories originating from fats – consuming large amounts of fats is not easy. Unless steps are taken to provide enough energy from other substrates (mainly from complex carbohydrates) to replace the fat in the diet, athletes may be in a state of energy deficit, which in itself distorts sports results. So, while reduction in fat intake is generally useful, a conscious effort should be made to provide enough overall energy when fat intake is reduced. Since fats have more than double the calorific value compared to the same amount of protein or carbohydrates (9 kcal/gram-fats and 4 kcal/gram-cars/protein), double the amount of food must be added to compensate the difference in fats we eliminated from the diet.

Cholesterol, oils, butter and margarine are fats, but each of them has slightly different characteristics. One common feature of all lipids is that they are soluble in organic solvents but are not soluble in water. (Anyone who has tried to make an Italian salad dressing knows that this statement is correct. The oil in the dressing is always separated on the surface, regardless of how much and very long mixing of the dressing.) The term fats usually refers to lipids that are at room temperature in a solid state, and the expression of the oil is used for lipids that are liquid at room temperature. Lipids are usually found in the form of triglycerides, consisting of three fatty acids and one glycerol molecule (hence the name triglycerides). Despite numerous forms, we can incorporate fats into food or create them in the body by combining carbon units from other substances. Almost every cell in the body has the ability to produce cholesterol; Individuals may have high blood cholesterol levels even if they adhere to a diet based on low cholesterol intake. We can also produce phospholipids, triglycerides and oils. In fact, it is precisely our ability to efficiently produce different types of fat limits the need to consume large amounts of lipids.

Fats functions

Intake of certain amount of fats, between 20 and 35% of the total intake, it is necessary to provide sufficient amount of energy and nutrients. Vitamins soluble in fats (liposoluble vitamins), which include vitamins A, D, E and K, must be taken with high-fat foods. Essential fatty acids, which are needed for specific body functions that we can not synthesize ourselves, must also be entered in optimal amounts. Some types of food fats are also needed to create a sense of satiety during meals, creating an important physiological signal that it is time to stop eating. Fats from fatty groceries have a longer period of gastric discharge than carbohydrates, which contributes to the sense of satiety. Of course, fat is also responsible for the good taste of food.

Lipid structure

Lipids have different levels of saturation, which is the term that refers to the number of double bonds in the chain of carbon atoms. Fatty acids without double bonds are saturated, those with one double bond are monounsaturated, and those with multiple bonds are called polyunsaturated fatty acids. Single bond connections are stronger and less chemical reactive than double bonds – as more double bonds, fatty acid has more possibilities to react with chemical environment. Precisely because of this different chemical reactive capability, the number of double bonds are an important factor in human nutrition.

Saturated fatty acids prevail in animal fats, palm and coconut oil. Monounsaturated fats are the most common in olive oil and canolin oil, but they are also found in animal fats. Polyunsaturated fats have the highest content in cold sea fish and vegetable oils (with the exception of olive oil that is more than 75% monounsaturated, coconut which is 85% saturated and palm oil which is 45% saturated and 41% monounsaturated). In the context of the recommended fat intake (> 30% of total calories), monounsaturated and polyunsaturated fats should constitute the majority of fats intake. Saturated fats are associated with an increased risk of hypercholesterolaemia (increased cholesterol levels in the blood), so that their intake should be kept to a minimum whenever possible. This is most easily achieved by reducing the consumption of animal fats, chocolate sweets (often containing a high level of saturated tropical oils), fried foods and dairy products with a high percentage of fat.

Triglycerides

Most consumed lipids are triglycerides, which contain 3 fatty acids and one glycerol molecule. Fats are deposited in the body in the form of triglycerides, which we produce when an excessive amount of energy is introduced into the diet. Triglycerides are deposited in the adipose (fatty) tissue, where grouped fat cells are located within the muscle cells (so-called intramuscular triglycerides). Both depots of fat are available to us as a source of energy when needed. When fats burn up as a source of energy, deposited triglycerides are taken from fat or muscle tissue, and each fat molecule is broken down into its constituent fatty acids and the glycerol molecule. In addition, each fatty acid is further decomposed into two carbon units for the production of ATP, in order to produce metabolic heat and energy for the operation of the muscles. This process is called beta-oxidation due to the fact that oxygen is necessary for the combustion of fats, other than carbohydrates.

Glycerol is a unique form of lipids which degradation is similar to the consumption of carbohydrates before fat, and it is also an effective humectant (good water retention). Some athletes who deal with endurance disciplines believe that glycerol intake helps them retain more water (a phenomenon known as hyperhydration or superhydration) than drinking water alone.

In an extremely warm and humid environment, water loss will certainly be greater than the athlete’s ability to compensate fluid, so starting the competition in a hyperhydrated state could have some benefits. In studies performed on tennis players and triathlets, certain athletes who consumed glycerol prior to the competition determined certain protective effects of hyperhydration, especially when practicing at high temperatures. However, the state of superhydration is likely to cause a certain degree of discomfort to be accustomed to. Athletes who drink liquids containing glycerol often describe the feeling of retaining additional water in the body as a feeling that they have become “water machines”, or as a feeling of “weight” or “stiffness”. However, they maintain that it is how they feel at the end of the race more important than how they feel at the beginning, so adding glycerol to liquids that drink before the competition has become a standard protocol for some athletes.

Essential fatty acids

Linoleic (omega-6) and linoleic (omega-3) fatty acids are essential fatty acids; although they are necessary for metabolic processes, the human organism can not synthesize them. The classification of omega-6 means that these fatty acids, which are polyunsaturated, have the last double bond on the 6th carbon atom. The classification of omega-3 indicates those fatty acids having the last dual bond on the 3rd carbon atom. Linoleic acid is an essential part of the cellular lipid membrane and is necessary for normal skin health. Linoleic acid is essential for the function and development of the nervous system. AMDR for omega-6 fatty acids is 5-10 grams per day, and for omega-3 fatty acids 0.6 to 1.2 grams per day. Both fatty acids are easily obtained from vegetable oil (corn, sunflower, canola, etc.) and from fish oil of cold deep seas.

Fish-liver oils rich in omega-3 acids have recently taken a lot of attention. These oils have been shown to reduce the ability of red blood cells to coagulate, thereby reducing the chance of an unwanted blood clot (thrombus). This reduces the risk of heart attack, which is most often caused by the formation of a clot in one of the major cardiac arteries. Deep-sea fish oils are the main source of two omega-3 fatty acids – eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The use of cold-sea fish (salmon, albacore tuna, Atlantic Herring) in feeding only once a week is enough to significantly reduce the risk of heart attack and stroke. Despite these findings, excessive intake of these fish oils may cause certain disorders, including an increase in oxidative cell damage. The best practice is to introduce fish intake as a regular part of a weekly diet plan so that supplemental intake of omega-3 fatty acids becomes unnecessary.

Fat needs

From the point of view of exercise, there is no reason to believe that an increase in fat intake results in an improvement in sporting results, unless the increased fat intake is the only reasonable means for athletes to get enough energy. Athletes who need more than 4000kcal every day to satisfy the combined needs of growth, exercise and tissue regeneration may require a moderate increase in intake of fat in the diet (preferably of vegetable or fish origin). Since fats are more concentrated form of energy both from carbohydrates and proteins, more energy can be introduced into smaller amounts of food if the foods contain more fat. If an athlete attempts to completely stop the intake of fat, he would need to consume so much food that it would become impossible to organize sufficient meals or allocate enough time for meals to consume the needed energy, which would lead to inadequate energy intake.

Lipids and physical activity

Even the most slimmer and healthier athletes have significant energy reserves in the form of deposited lipids. Average deposits of energy in the fat tissue range between 50,000 and 100,000kcal, which is enough energy to pass or run 800 to 1600km without the need for additional fuel inputs. In addition to the aforementioned fatty tissue reserves, athletes have supplies of approximately 2000 to 3000kcal in the lipids within the muscle tissue. Fats kept in the form of triglycerides are available as fuel under certain conditions of oxygen availability. Maximum fat oxidation occurs when exercising an intensity of 60-65% VO2max. At a higher intensity of exercise, fats continue to burn, but the distribution of energy is changing – primary fuel becomes carbohydrates.

Triglycerides deposited in the fat tissue dissolve on their constituent molecules, glycerol and fatty acids, and then enter the circulation. Glycerol is available to all tissues for energy metabolism, and free fatty acids are transmitted to the active muscles, where they oxidize to gain energy. Triglycerides deposited in muscles also dissolve on glycerol and fatty acids – fatty acids burn out to gain energy wherever they can. And glycerol can burn in active muscles, for energy support, or it can be transported to blood plasma as a source of energy for other tissues.

The lower the intensity of exercise, the greater the proportion of fats that burns to meet energy needs. As exercise intensity increases, the proportion of burning fat decreases and the proportion of carbohydrates increases as the dominant energy source. This basic fact is the main reason why so many people are engaged in low-intensity activities to burn accumulated lipids and lower body fat levels. However, the ratio of burnt fats should not be mixed with the total amount of lipids consumed at different intensities of physical activity. As the intensity of physical activity increases, the total number of calories burned per unit of time increases. Although the percentage of fat burning at the given intensity of exercise can be reduced. The total amount of fats consumed in calories and grams is higher, as the total energy demand is higher. The teaching of these facts about metabolism is that athletes who want to reduce the body fat content should exercise at least at 65% VO2max level, but also with higher intensity, with a consistent duration of training to optimize the fats consumed. Exercising at low fat intensity burns as the dominant source of energy, but the overall amount of fat consumed is lower than in high intensity training.

Advanced sports nutrition

Dan Benardot

Marko Popin

🇬🇧 Advanced student of medical science and nutrition expert, skyrunner and dog lover.

🇷🇸 Apsolvent medicine i ekspert za ishranu, skyrunner i ljubitelj pasa.

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