Fat burning: how does it work?

Which athlete does not want to be the "lean mean fighting machine"? Burning fat is often talked about as the road to becoming such a machine. Fat burning is a common topic of conversation amongst athletes and non-athletes.

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Why fat burning?

In today's society, as a population, we are not burning enough fat (calories) and we are eating more fat (and more calories) than we burn. It is therefore not surprising that people are searching for ways to "burn more fat" (ideally ways that do not require too much effort).

Many companies have recognized the potential and have jumped on the opportunity and are now selling tools that help you monitor fat burning and supplements that supposedly increase fat burning. But do these things really work? Are there easy ways to increase fat burning? Are there easy ways to become lean?

People are searching for ways to "burn more fat"

Back to basics

Let’s go back to the basics and the simple facts first. Let’s looks at what the evidence says and what we really know. In a series of articles on mysportscience.com I want to evaluate the following:

1. What is fat burning? And how is it regulated in the body?

2. What are the main reasons why people/athletes want to burn fat?

3. What is the evidence for each of these reasons?

4. If we want to burn fat, what are the best methods to do this?

5. Can we come up with some general advice?

Let’s start with the very basics. Fat burning or fat oxidation (the term preferred by scientists) occurs on a daily basis in virtually all cells of our body.

Fat storage and use

Fat is stored in the form of triglycerides. A triglyceride is made up of 3 fatty acids that are held together by a glycerol backbone (hence the name tri-glyceride). Only fatty acids can be used as a fuel. Therefore triglycerides first need to be broken down into fatty acids. The fatty acids then need to be broken down further.

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How do we oxidise fat?

Fat oxidation refers to the process of breaking down fatty acids. To oxidize fat one needs:

  1. Healthy mitochondria (small structures in cells that serve as the power plants of the cells. In these power plants, energy is generated for muscle contraction by burning fuel, using oxygen and producing carbon dioxide).