One Look One Take

We talk a lot about dieting and burning off fat, but we actually have a lot of misconceptions about weight loss. Some people think fat is converted into energy or heat—a violation of the law of conservation of mass—while others think that the fat is somehow excreted or even converted to muscle. I was told early on that you can never lose your fat cells (adipose) once you gain them...they just shrink if you work it off. 

When you lose weight, you exhale your fat. 

There are surprising ignorance and confusion about the metabolic process of weight loss. The correct answer is that most of the mass is breathed out as carbon dioxide, it goes into thin air

chemical compounds called triglycerides (which consist of carbon, hydrogen, and oxygen) and then stored in the lipid droplets of fat cells. To lose weight, you’re attempting to metabolise those triglycerides, and that means unlocking the carbon that’s stored in your fat cells. 

Losing 10 kilogrammes of human fat requires the inhalation of 29 kilogrammes of oxygen, producing 28 kilogrammes of carbon dioxide and 11 kilogrammes of water. That’s the metabolic fate of fat. 

Then the duo calculated the proportion of the mass stored in those 10 kilogrammes of fat that exists as carbon dioxide and as water when we lose weight. By tracing the pathway of those atoms out of the body, they found that 8.4 of those kilogrammes are exhaled as carbon dioxide. Turns out, our lungs are the primary excretory organ for weight loss. The remaining 1.6 kilogrammes becomes water, which is excreted in urine, faeces, sweat, breath, tears, and other bodily fluids.

So, for this upcoming post-holiday season, should we all just exhale more to shed those extra pounds? No. Breathing more than required by a person’s metabolic rate leads to hyperventilation, followed by dizziness, palpitations, and loss of consciousness.