How "Fat Burning" Works
By Mike Hazle, Oct 12, 2021

Fat Metabolism
“Fat burning”, also known as fat oxidization or fat utilization, is a 3-part process. You can’t burn fat, but you can oxidize it.
- Part 1: Fat mobilization – Also known as Lipolysis, it helps move fat cells out of our tissues. Stored fat has 2 parts, the fatty acid and glycerol, linked together by a backbone. You need to “break that backbone” to mobilize fat out of the stored location so that it can be used as energy.
- Part 2 & 3: Fat transport and oxidation - Fatty acids (potential fuel) need to go into cells to be used for energy, but then those cells must be oxidized so that fatty acids can move to the mitochondria to become ATP.
If you only mobilize the fat cells but do not oxidize them, they will be returned to stored fat. The oxidizing of fat helps with the increase of glucagon (GLP1) and decrease of insulin.
The Role of Carbon
- Carbon is the building block of life, the essential element to all organic matter. Fats, Carbohydrates, and Proteins are all made up of carbon chains.
- Losing fat or weight is accomplished simply by releasing more carbon than you take in, essentially a caloric deficit.
- Essentially, Fat Oxidation is the breaking of Carbon bonds which results in energy (used to produce ATP) and a leftover Carbon atom. Carbon combines with oxygen to form Carbon Dioxide released during respiration.
- Fat is not lost through sweat, urine, or stool. FAT IS LOST ONE CARBON ATOM AT A TIME AND ONE BREATH AT A TIME!
The Types of Fat
- White Fat – The subcutaneous fat under the skin.
- Brown Fat – Primarily found between shoulder blades and the back of neck, brown fat is filled with tons of mitochondria. It can take food and break it down into energy within the cells. White fat cannot do that. It can use energy directly, but it skips the mobilization process.
- Beige fat – This is the adipose tissue that we are trying to lose.
Training for Fat Loss
- High intensity exercises such as sprint interval training (SIT) and high intensity interval training (HIIT) burn more glycogen during the exercise and more fat after the exercise.
- The opposite is true for moderate intensity training (MICT) for time over 90min of work. More fat is burned during the exercise.