Have you ever wondered where all the fat goes when you lose weight?

Does it melt away? Does it evaporate? Or do we excrete it out in our bodily fluids?

The correct answer to this question may surprise you… we breathe most of it out!

A study published in the British Medical Journal back in 2014 revealed that 10 kg of fat turns into 8.4 kg of carbon dioxide, which is exhaled when we breathe, and 1.6 kg of water, which we then excrete through bodily fluids like our urine, sweat and tears. When we put on weight, fat is stored in fat cells as triglycerides – and these compounds are made up of carbon, hydrogen, and oxygen. Triglycerides an efficient way to store energy in our reserve tanks when needed for later use. Very handy in the caveman era when food was not so easy to come by.

So, to lose weight, you going to need 2 things:

Number one – an energy deficit AND

Number two – a way to get rid of all that extra energy!

First, the energy deficit. In order to lose 10kg, you would need to burn 94,000 calories. And if you wanted to lose that weight in, say 3 months, that works out to be a calorie deficit of about 1000 calories a day – easy right???


We all know that “eating less and moving more” is an oversimplistic way of thinking about weight loss. At Alevia Medical Weight Loss, our doctors show you ways that you can lose weight AND enjoy a range of healthy foods without feeling restricted or deprived. In the words of our great Dr Andrea Ryan – our job is to help you find a calorie deficit, that does not suck!

Okay, so you have burnt a whole lot of energy and you are losing weight, now where does all that fat go?

Well, in order to break down 10kg of fat, you would need to first inhale about 29 kg of oxygen (that is a whole lot of breathing right there!). The result is that from those 10kg of little fatty acids stored up in your fat cells, 8.6kg would be breathed out as CO2 and 1.4kg would lose as water and excreted in bodily fluids such as urine, faeces, tears and sweat. Therefore, you could say that your lungs are helping you to blow off a lot of your fat stores! Your lungs become your primary fat excretion organ! Who would have thought it?

So, you might be thinking “Does this mean that if I just huff and puff for a while, then I’ll start losing weight?” Unfortunately, no! You must create an energy deficit first to unlock those fat cells and free up that reserve fuel – and that is where our Alevia doctors can help you!

It is important to note that the process described above applies to the breakdown of body fat in general. Spot reduction (losing fat from specific areas of the body) is not possible through targeted exercises or specific diets. When you lose weight, your body tends to reduce fat stores from various parts of the body, depending on genetic factors and individual characteristics.

Alevia Medical Weight Loss are YOUR team of bariatric doctors, dietitians and exercise physiologists that can help you to unlock both your fat cells AND your health! With yummy dietary plans and weight loss medications to help curb the hunger and cravings – we have got you covered. Give us a call if you would like some help to blow off a bit of CO2 today!

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