Weight loss is a major goal for so many people. But so few actually understand where fat goes when we lose weight. An article published in The BMJ has explained where fat goes when we 'lose weight'.
What is fat?
It's important to understand that the 'fat' we want to lose is very different to the fat consumed in the diet.
Put simply, when we want to lose body fat, we are attempting to metabolise the triglycerides that are stored in our fat cells. These triglycerides can be made from any of the macro-nutrients – protein, carbohydrate or fats.
What is the metabolism?
The metabolism, according to biological terms, is all of the chemical reactions our bodies undergo to keep us alive.
There are two main categories of metabolism: Catabolism is breaking down molecules to obtain energy. Anabolism is synthesising compounds for the cells to use.
How does the body utilise fat for energy?
The body puts the stored triglycerides through a process known as oxidation. This takes the triglyceride and converts it to carbon dioxide, water and energy. This is a catabolic process, as it involves breaking down the triglyceride in order to obtain energy.
Where does the fat go?
So if this is the process that we go through to lose fat, where does the majority of the fat go? Interestingly, it's not excreted how you might think. According to the scientific formula, the majority of the weight loss is carbon dioxide.
If you were to lose 1 metric kilogram of fat, 840 grams of the weight would be exhaled as carbon dioxide. The other 160 grams would be excreted as water, through elimination channels such as sweat, tears, urine, faeces, breath or other bodily fluids.
So essentially, when you lose weight, you lose over 80% of it through your lungs! This is why both diet and exercise are essential tools in losing and maintaining a healthy loss of body fat.