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How fat is beneficial to your running

April 06 2022 6 min read

When we think of fat, it conjures up images of greasy food that causes havoc to our diets. However, there is another side of fat you may not have considered.

Fat is definitely not the enemy it was once perceived as, and it’s important to understand the role it can play in your training. By harnessing the powers of those good fats, you could be seeing some great results!


Power athletes understand how protein plays a key role in repairing muscle, allowing you to train harder and more effectively. Now a small band of endurance runners are looking at fat and how tapping into our body’s incredible reserves can make you better at long distance events.

But before you start reaching for the burgers, we’ve chatted with professor John Brewer to make sure we all have a clear understanding of what is going on when it comes to our fat intake.

“Fat is important as it contains essential vitamins and amino acids. But most of us get enough fat in our diets, so there is no need for fat supplementation - the energy density of fat is very high, with over double the number of calories per gramme than a gramme of carbohydrate,” he says. “So, eating too much fat can quickly cause weight gain, and most of us have enough fat stored on our bodies to provide enough energy to run 40 consecutive marathons.”

A typical person can store about 2,500 calories of carbohydrates, which is only enough to last a couple of hours at most. In comparison, the typical person also carries a reservoir of about 50,000 from fat.

That’s a lot of untapped fuel!

Ultra-distance runners are particularly interested in those reserves which can be harnessed by triggering fat adaptation.


When planning your running diet to include fat, stick to a conventional high-carb diet as normal for most training. However, skip your usual carbs before key workouts, like a hard run in the morning before breakfast. These targeted sessions are enough to boost the body’s fat-burning ability without compromising its carb burning.


Fat absorbs vitamins A, D, E and K as well as providing fatty acids that your body cannot generate on its own. They key is to eat good fats such as:

  • Oily fish
  • Nuts and seeds
  • Sunflower or rapeseed oil
  • Avocados

Ultimately, you should steer clear of saturated fats, but don’t be frightened of their ‘good’ relatives. Chips are best saved for special occasions, but oily fish is for training! The fitter you become, the more efficient your body will get at burning fat as a fuel, especially for sessions more than an hour in length.


  • Dietary fat is essential for good health, however, it is still generally believed we eat too much. To promote good health it is recommended that you consume between 30-35% of total energy intake.
  • A lower fat diet should not become a no fat diet due to some of the important functions of fats.
  • Fat acts as the body’s backup storage fuel secondary to carbohydrate in a concentrated form. One gram of fat provides 9 kilocalories of energy.
  • At rest it contributes around 75-80% to your energy needs.
  • Fats protect vital organs, provide a structural material for cell walls and act as an insulator preventing heat loss.
  • Animal fats are a source of the fat-soluble vitamins A, D, E, and K, whilst fat also provides flavour and texture to foods, features often leading to overconsumption.
  • Although the body can synthesise most of the fat it requires, like proteins, linolenic and linoleic acid are essential unsaturated fatty acids that the body requires for good health and these must be provided by the diet. Both function as building blocks for other important fatty acids and play a vital role in the development of every single cell in the body, as well as assisting in the regulation of blood pressure and immune responses.
  • Very low-fat diets can have negative effects on health and performance. To protect health athletes are encouraged not to drop their fat intake below 20% of their total energy intake as there appear to be no additional performance benefit.

Visit the England Athletics website for more help and advice on running and keeping fit.

You can also head over to the Fitness First blog for more information on nutrition and dieting.