Where does fat go when we lose weight?

Does fat turn into muscle? Do I “poo” the fat when I lose weight? Where does it go?

These are common questions I am asked almost daily, and the usual answers found on the internet or given by health and beauty practitioners, even cosmetic doctors (in fact, especially by cosmetic doctors) show a total lack of the laws of physics and biology. Find out the truth below.

When somebody loses weight, where does the fat go?

Turning fat into muscle?

When scientist Ruben Meerman asked doctors, dieticians and personal trainers the question "When somebody loses weight, where does the fat go?", the vast majority of them answered that fat becomes energy (something that is only possible with a nuclear reaction), faeces or muscle, with all answers being wrong, of course.

In fact, basic, high school-level chemistry explains that whenever an organic chemical is "burned" (oxidised), it ends up as carbon dioxide and water - as simple as that.

So after being "burned" in the body and releasing energy - NOT becoming energy - fat ends up as carbon dioxide and water. The carbon dioxide is exhaled by the lungs and the water is expelled as sweat and urine. Nothing becomes faeces, nothing becomes muscle and - thank God - no nuclear reaction occurs in our bodies to transform matter (fat) into energy.

However, I am not surprised by such myths, given the fact that most doctors and aesthetic practitioners believe:

  • that we have a set number of fat cells in our body throughout our life (which is totally incorrect)

  • that liposuction permanently removes fat from a given area (also incorrect)

  • that fat released by non-surgical fat reduction or cellulite treatments is so much that it can actually harm the liver (🙄eyes rolled for the unforgivable ignorance, especially for cosmetic doctors).

How do we excrete the fat that we store in our body after “burning” it?

Going back to the question of what happens to the fat after being burned with diet and/or exercise, Ruben Meerman actually conducted some research and found out that to completely burn 10 kg of fat, we require to breathe in 29 kg of oxygen and to breathe out 28 kg of carbon dioxide and sweat away or urinate 11 kg of water!

So in summary, we lose most of our fat through our lungs, in the form of carbon dioxide, and through our skin and urinary system, in the form of water.

Ruben has published these facts in the British Medical Journal and at the closing paragraph of his paper he stated: "We recommend these concepts be included in secondary school science curriculums and university biochemistry courses to correct widespread misconceptions about weight loss."

I really couldn't agree more. Guys, open a book and do some study!

Where do fat cells go after losing weight?

I guess if you were to ask the same people where do the fat cells that stored the fat go, they would tell you the usual “they get broken down by the body’s natural processes and eliminated by the lymphatic system”, which is equally wrong (but that doesn’t stop me hearing it all the time).

The correct answer, of course, is: nowhere. Fat cells don’t go anywhere when you lose weight. They stay put and wait for you to overeat and fill them again, hence putting on weight on the same spots after weight loss.

Just to get things straight.


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