How do you burn fat?
I often get this question – but the context is essential to have in mind! Fat is an energy source the body needs – also when running.
For the most part, the body uses a combination of glucose (sugar/carbohydrates) and fat, with the higher intensity leading to higher usage of glucose as the energy source – since the body needs more oxygen to "turn fat into speed", compared to glucose. Therefore, the body switches to glucose when the intensity increases.
Is it the way to burn fat on the stomach?
It is essential to understand that the energy source you use when running doesn't directly correlate with losing weight or not – neither on the stomach nor elsewhere. The only important thing is which depots the body consumes during a run.
If you are planning a diet, it is in its entirety about calorie consumption over calorie intake – not whether you burn fat or glucose during your run!
To lose weight, you need to consume fewer calories than you intake. You accomplish that by either eating less or by being more active. Or both at the same time. It is that simple.
When losing weight, it is not life or death, whether you run far and slow (and uses fat as the primary energy source) or run shorter and faster (and uses glucose as the primary energy source). What matters is the total energy consumption and intake (calorie consumption/intake) – and not if you primarily have used fat or glucose as fuel for your run.
All types of running, no matter the distance and pace, contribute positively towards you losing weight because it increases your daily calorie consumption. As long as you consume fewer calories than you burn, you will lose weight.
An advantage to increasing fat burning?
With the knowledge that the body demands more oxygen to convert fat to speed compared to glucose, one must consider why it is even enjoyable to increase fat burn during running?
- At the moment, it can actually be difficult or even impossible to fill the depots with as many carbohydrates as you burn when you run. What it entails is that you, during a run, gradually empty your glucose depots (also known as glycogen depots).
When improving your abilities to burn fat, you tear less on your glycogen depots, reducing the risk of going sugar cold – or "hitting a brick wall".
Glucose is always the quickest solution
To point it out one more time – glucose is always the quickest solution! You can run faster with glucose than fat, no matter how effectively you burn fat.
Therefore, if you can reach the finish line before running empty on glucose during a run, it is not an advantage for your time to try and improve fat burning. It is also why the recommendation is to consume carbohydrates for the long race – allowing you to run as much as possible at your maximum intensity.Det er også af denne grund, at det kan anbefales at indtage kulhydrater på de lange løb, så du kan løbe så meget som muligt med så høj intensitet som muligt.
The long runs and fat burn – how far?
If you run far enough to put yourself at risk of running dry of glucose during a run, then it is advantageous to improve your body fat-burning ability, cf the above. How long it takes for you to run empty depends on other things – including diet and training style.
If you are running for 2 hours or more, there is a risk of running out before reaching the finish line - some even after 1½ hour. If you manage your energy poorly, you may end up emptying the depots much faster, e.g. by an intensive workout.
How to improve your fat burning ability
If you want to improve your body's ability to burn fat during a run, then there are multiple factors you can work with during your run.
First and foremost, body fat needs more oxygen to convert, so you must design some significant intervals that improve your maximum oxygen uptake (VO2max).
Want to check out examples for interval training to improve VO2max, then read more in this article
Besides working with your oxygen uptake, you can easily feature some runs with low intensity. If you run with a low enough intensity, your body will use body fat as an energy source during your run, which means you stimulate the active enzymes when burning body fat. The result is that you receive more enzymes, thereby burning body fat better.
It is quite a big difference in how low the intensity needs to be to burn fat. Some people are perfect at burning fat naturally, while others have difficulties improving the process. As a rule of thumb, you run at a pace where you can also eat. Then you can be confident knowing that the intensity is low enough to burn fat.
If you know your max pulse, you can try keeping your pulse under 65% of your heart rate max.
