With so much contradicting information in the media regarding fats in the diet, it’s easy to understand why there’s so much confusion. Dietary advice and recent trends appear to have taken a complete 360 degree turn in recent years, going from consuming as little fat as possible to the increasingly popular switch to low carbohydrate/ high fat or ketogenic diets.
So, should we be consuming fats in the diet and if so, how much? We’ll take a look at the different kinds of fats, their roles in the body and the food they come from to give you a better understanding of this key macronutrient.
What are fats used for?
Fats are one of the three macronutrients our bodies need, and they are an essential part of everyone’s diet and vital to health. They not only provide an import source of energy, but also ensure the body receives enough fat-soluble vitamins and essential fatty acids, as well as regulating the production of hormones, providing insulation and protecting the organs(1). Dietary fats are particularly important for adolescent athletes to ensure healthy maturation, as the demands of the body are much higher due to increased periods of rapid growth and development, combined with intense sporting schedules(1). Excess fat will be stored in the body to be broken down and used as an energy source for low intensity activities(2). But for athletes, it’s important to remember that this process isn’t as efficient as using carbohydrates for fuel, especially so in high intensity exercise(3) and it’s not necessary to supplement the diet with increased fats prior to exercise, in the same way as with carbohydrates(4).
Are there really ‘good’ fats and ‘bad’ fats?
Whilst some amount of (most) fats are essential to the diet and health, high intakes of saturated fats have been widely associated with negative health outcomes, in particular heart disease(5). This has led to recommendations suggesting reducing saturated fat intake, giving preference to the unsaturated forms. But, recent research has emerged claiming that saturated fat isn’t so bad after all(6).
So, is saturated fat actually bad?
Saturated fats are found mostly in animal products, such as meat and dairy, and are usually solid at room temperature (think of butter). It has been widely associated with negative health effects, particularly in relation to coronary heart disease (CHD). This is because it causes an increase in low-density lipoproteins (LDL), or what is more commonly referred to as the ‘bad’ cholesterol. LDL is deposited in the arteries, which, when it builds up, can restrict blood flow and increase the risk of heart attacks.
The majority of current guidelines on fat consumption come from research carried out in the 1970’s, which found that rates of heart disease were much higher in individuals who consumed more saturated fats in their diets(5). However, these recommendations have come under huge scrutiny recently, with the publication of new evidence suggesting saturated fat isn’t as bad as first believed(6) and some forms may even be beneficial to health! This evidence, however, must be interpreted with some caution. It’s important to realise that not all saturated fats are the same or have the same effect in the body and in this recent research, the fats that were shown to be beneficial (pentadecanoic and margaric acids- found in dairy), aren’t as abundant in the diet as those with the negative effects (stearic and palmitic acids- found in meat and other animal products).
Unsaturated fats are split into two categories; monounsaturated and polyunsaturated and come from foods such as oils, nuts, seeds, avocados and some fish.
Monounsaturated fats help to lower the ‘bad’ LDL cholesterol and raise the ‘good’ HDL (high-density lipoproteins), responsible for removing the cholesterol from the vessels and taking it back to the liver where it can be excreted from the body (7).
Polyunsaturated fats include omega-3 and 6 fats, which cannot be made by the body in high enough quantities and so are considered to be essential fats which must be consumed in the diet(7). Oily fish like salmon, sardines, and mackerel are a great source of these essential fatty acids, and young athletes should aim to eat at least one portion of oily fish per week.
Whilst there might be some contention as to whether saturated or unsaturated fats are better for health, its commonly agreed that trans fats are the ‘bad’ ones. Most trans fats are artificial fats, created during industrial processes to turn fats from liquids to solids, usually to save money or extend shelf life. They’re most commonly found in highly processed foods such as ready meals, margarines, biscuits and cakes; however, they’re often hidden. The best way to check if a food contains trans fats is to look on the nutritional label for total grams of trans fats, or to look for any hydrogenated ingredients in the list. These types of fat should be limited, as consumption has been widely associated with negative health effects such as heart disease
Because there aren’t specific recommendations for fat intakes of athletes, it is recommended that they follow the same guidelines as the general population. In the UK, total fat intake is recommended (over 5 years) to be 20-35% of total energy intake, with a maximum of 70g per day for those consuming 2000 kcals. No more than 10% being saturated fat (20g for those consuming 2000 kcals)(8).
So, whilst some fats are essential to health, well-being and performance, young athletes do need to be aware of the different types and the potential impact on their body. Although you don’t need to cut out saturated fat entirely, preference should be given to lean meats and dairy over processed meats such as burgers and sausages. And the biggest proportion of fat in the diet needs to come from unsaturated forms including oily fish, nuts, seeds, oils and avocados to promote health benefits. But remember, because fat sits in the stomach for longer, it's best not to consume them before a training session or workout.
- Smith, J., Holmes, M. and McAllister, M. (2015). Nutritional Considerations for Performance in Young Athletes.Journal of Sports Medicine, 2015, pp.1-13.
- SACN (2019).Saturated fats and health. [online] Available at: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/814995/SACN_report_on_saturated_fat_and_health.pdf
- Girard, S.E (2014).Endurance Sports Nutrition. 3rd ed. Illinois: Human Kinetics.
- Bjorntorp, P. (1991). Importance of fat as a support nutrient for energy: Metabolism of athletes.Journal of Sports Sciences, 9(sup1), pp.71-76.
- Keys A. Coronary heart disease in seven countries. Circulation. 1970;41(S1):118-139.
- Chowdhury, R. et al., (2014). Association of Dietary, Circulating, and Supplement Fatty Acids With Coronary Risk. Annals of Internal Medicine, 160(6), p.398.
- Lunn, J. and Theobald, H. (2006). The health effects of dietary unsaturated fatty acids. Nutrition Bulletin, 31(3), pp.178-224.
- Public Health England. (2019). Government Dietary Recommendations. [online] Available at: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/618167/government_dietary_recommendations.pdf