Fats Part 2: What are fats used for in the body?

healthy glass of milk
Simon Long

Simon Long

Simon is a highly experienced personal trainer and behavioural psychology expert
View My LinkedIn Profile

In Fats Part 1 we spoke about the different types of fats that exist and are present in our diet.

Today, we’re going to cover the bodies uses of those fats.

Use 1: A super dense storage of energy

As discussed in Carbs Part 2 the body has a storage of around 6 to 15 grams of carbs in its body, in the form of glycogen. This equates to around 24 to 60 calories of energy per kg of body weight. In an average 70kg male there would be between 1680 and 4200 calories in total.

That same male would also have, on average, around 15% of his body weight as fat (The average female has 25% of body fat). This would mean that he is holding 10.5kgs of fat on his body. As each gram of fat contains 9 calories of energy this results in his stores being worth 94,500 calories of energy. When compared next to the absolute maximum of 4200 calories of energy in glycogen you can see that it is a very large store of energy.

Use 2: A source of energy

Fat can also be oxidised, or metabolised, by the body to create energy. It does have the distinct disadvantage when compared to carbohydrates of being twice as slow to produce energy and for each reaction to be slightly less efficient at producing energy then the same reaction done with carbs.

This is mainly due to the fact that the fat needs to go through lipolysis to be released from the fat stores in the adipose tissue. It then needs to attach itself to Albumin so that it can be transported around the body. Once it reaches its destination it needs to be absorbed by the tissues. Once this has all occurred it uses the same metabolic pathways as carbs.

There is a very big advantage to using fat for energy though. Firstly, as discussed above, it is a very large storage of energy, if other factors, such as muscular and central nervous fatigue, did not occur then 94,500 calories could keep you running at an average pace for 135 hours.

Therefore using this energy whenever possible allows the body to spare the more efficient energy, carbs, that is in a much smaller supply. This then allows the body to use this energy when a higher intensity of exercise is required. For example if you ran a marathon using your carbs as energy then by the time you reach the end of the race you may have run out of carbs. This means that if everyone around you kicked for the line and began to sprint in the final mile you would be unable to keep up, as you would not have anything left that could create energy fast enough to power your legs.

However by using fat as the energy source during the steady speed phase of the marathon you have saved your carb, or glycogen, stores. This means that when you pick up the pace to a sprint in the final stages your body can just switch from using fats to produce energy to using carbs. They will be able to produce enough energy for you to maintain the pace, which will hopefully win you this race!

For more information on how your body uses fats and carbs during exercise keep your ear to the ground for future articles. A great way to do this is by following me on your chosen social media platform. Links are above and below.

Use 3: Transportation of vitamins

Certain vitamins in our diet, namely A, D, E and K, are fat soluble. This means that without fat they are unable to be transported around the body to where they are needed.

This will eventually lead to vitamin deficiency for these vitamins, even if a sufficient amount is being consumed in the diet.

Use 4: Protection of internal organs

A lot of the bodies fat is stored around the mid-section in subcutaneous tissue. This fat provides ‘shock absorption’ for any impacts or trauma to this part of the body, which contains many of the vital organs but does not have the protection of a rib cage.

Use 5: Thermo regulation

Fat acts as a very good insulator, meaning that in cold stresses it will allow the individual to maintain a higher body temperature, staving off conditions such as hypothermia for a longer period of time.

It is worth keeping in mind though that larger fat stores also make it harder for the body to cool itself down when it is subjected to warm temperatures or intense exercise.

Use 6: A hunger suppressor

Many professionals, including myself, feel that a slightly higher than average intake of fat when you are on a weight loss diet is beneficial.

One of the reasons for this is that when fat is consumed it is digested and absorbed into the blood stream very slowly. On average it takes the body 3.5 hours to clear the stomach of fat that you consume. This leaves you feeling fuller for longer and so hunger pangs are kept at bay. This in turn means that less calories will be consumed over the day.


And that’s the bodies main uses of fat. I hope that you are finding these articles on the macro nutrients useful. The more you know about what you are consuming, whether you are trying to drop fat or build muscle, the more successful you will be.

Keep a look out for future articles, including protein uses, and the uses of carbs and fat during exercise. A great way to be the first in the know is to follow me on social media. The links can be found below or at the top of the page.

As always if you have any questions give me a shout. If you have any comments them stick them in below. I always read them.

If you would like to take the next step in improving your health and fitness then come and see me for your no obligation consultation and assessment.

Did you find this article helpful? Why not share it on your social media profile so that others can benefit?

Do you know someone who could benefit from seeing this article? Then please feel free to send it to them.

For the latest articles, videos, offers and to see what I am up to you can follow me on your preferred social media platform by following the links below:


Facebook- https://www.facebook.com/bodydevelopmentcentre?ref=hl

Twitter- https://twitter.com/BodyDevCentre

Youtube- https://www.youtube.com/channel/UC5E_OaCEoLCI0oVUh5sZcOw

Instagram-  https://instagram.com/bodydevelopmentcentre/

Google+- https://plus.google.com/u/0/b/115670079411668440729/115670079411668440729/about

Pintrest-  https://uk.pinterest.com/bodydevcentre/


Best wishes,

Si   =]