Where exactly does fat go when we lose it?

Where exactly does fat go when we lose it?

There are many things that we usually want in our lives: health, happiness, success…the list goes on and on, but there is one thing that we usually want less of: fat! If we were to lose our extra fat storage, where would it even go? The answer to that question might surprise you!

“Fat loss” and “weight loss” are commonly used terms in our society but how much do we really understand their meaning? Do we really just “lose” fat? Many may explain fat loss as burned energy but if we recall the law of conservation of mass1which states that mass is neither created nor destroyed this would mean that our atoms are not converted to other elements, they remain the same in chemical reactions, and they are just recycled into our ecosystem. The biggest chemical reaction in our bodies is known as our metabolism. We may have to use energy to “burn” fat but the end destination of fat may just go by another familiar name.

When our bodies begin to need excess energy (usually due to increased exercise) and it is not finding it from the food that we eat (by reducing the calories that we are consuming) then our bodies start tapping into its saved biological energy bank, our fat. The bank of fat then deals in triglyceride “currency.” Triglycerides are a string of carbons, hydrogen and oxygen together found in our fat cells2. In order to withdraw from this bank we need a chemical reaction as a transaction. Once triglycerides are metabolized or used as energy in the body we also produce water (sweat, urine, tears) and carbon dioxide; meaning that our stubborn fat is “lost” mainly through our lungs!

As we lose weight and fat we not only enrich our health by reducing our risk for disease but we also contribute to our beautiful earth! Who would have thought!? Plants and trees require carbon dioxide to grow. So as we lose fat mass they gain it3! Our adventurous journeys to our ideal weight might just come with a green thumb! 🙂


Maryann Walsh, MFN, RD

Registered Dietitian


1: https://www.nature.com/scitable/knowledge/library/the-conservation-of-mass-17395478/

2: https://www.bmj.com/content/349/bmj.g7257

3: https://www.canr.msu.edu/news/where_do_trees_get_their_mass_from