It has long been thought avoiding dietary fats is the is a safe option. It has been long exaggerated by the media, also (just like most news and science stories nowadays!). “Eating fat makes you fat!”, “Avoid fat like the plague!”, ”Zero-fat this, Zero-fat that!”. Let’s filter through the facts on fats.
Where It All Started
Research appeared to show low-fat diets were beneficial for health. Fat is calorie (kcal) dense; at 9 kcal per gram. Reducing fat intake may, therefore, serve well for reducing over calorie intake. If you’re aiming to lose weight, this may be a good option, since you must obtain a negative energy balance to do so (energy in LESS THAN energy out; aka energy deficit).
Low-carbohydrate, high fat diets have been associated with health benefits recently, but such diets have impaired performance in endurance athletes. For athletes, carbohydrate remains king!
Fat Helps You Function
Fat is important. They provide us with crucial vitamins – A, D, E, and K – that are fat-soluble (BDA). They NEED fat to be absorbed. There are different kinds of fat; some more beneficial than others.
There are two kinds of unsaturated fats – monounsaturated and polyunsaturated. Intake of monounsaturated fats, like almonds, peanuts, and olive oil, encourages healthy cholesterol in the blood. Polyunsaturated fats are found in sunflower or rapeseed oil (NHS). These could protect against heart disease amongst other advantages (McArdle, Katch, & Katch, 2014). Omega-3 fats are essential fatty acids. The body cannot make sufficient amounts of these. Oily fish, such as salmon and sardines, and nuts like walnuts and almonds, are good sources of these fats. Omega-3s help prevent blood clotting and have heart-healthy benefits.
Threats to our health arise if we eat too many saturated fats. They are, however, part of our diets and play a role in bodily cholesterol production. We need fat and cholesterol for hormonal function and other bodily processes (Lichtenstein et al., 1998).
We have two types of cholesterol – low-density lipoprotein (LDL) and high-density lipoprotein (HDL) – the latter is known as ‘good’ cholesterol. HDL sees where there is too much cholesterol and takes it to the liver where we can essentially get rid! High saturated fatty acid intake can increase LDL cholesterol, simultaneously increase your risk of coronary heart disease. One must take caution to not go overboard.
As with carbohydrate and protein, if we eat too much fat, this is not used by our body for energy but stored as fat instead, and can build up to high mounts in excess if we’re nor careful. It is very difficult to avoid dietary fat and follow a true ‘zero-fat’ diet, no matter how hard you may have tried. This is not a good idea, anyway!
Found in hydrogenated vegetable oils, cakes, and biscuits; trans fats raise also raise cholesterol. These have detrimental effects on LDL cholesterol, heart health, and cognition. We shouldn’t have more than 5 g/day (NHS).
Final Word on Fat
Eating too much fat puts you at risk of a caloric SURPLUS (energy in MORE THAN energy out) - causing weight gain. This is a good thing if your goal is healthy weight gain of around 0.5 kg/1 lb per week. If weight maintenance or loss are your aims; probably not so good. Sufficient intake of dietary fat is healthy - whether you’re aiming for energy MAINTENANCE (energy in = energy out), a DEFICIT, or SURPLUS.
If you‘ve looked at the recommendations and/or calculated how much carbohydrate and protein you require; the rest should come from fat. When buying foods, the ‘traffic light system’ is a good estimate of how much fat is in the food:
Fat – HIGH = 17.5 g/100 g; LOW = <3 g/100 g
Saturated Fat – HIGH = 5 g/100 g; LOW = <1.5 g/100 g
Lichtenstein, A. et al. (1998). Dietary Fat Consumption and Health. Nutrition Reviews, 56(5), 3-19.
McArdle, W., Katch, F., & Katch, Victor L. (2014). Exercise physiology: Nutrition, energy and human performance (Eighth edition; International ed.).
Article by Liam Oliver, Sports Nutrition Student at British Diving