Shed post-Christmas pounds just by breathing

PUBLIC RELEASE DATE:

16-Dec-2014

Contact: Emma Dickinson edickinson@bmj.com 44-020-738-36529 BMJ-British Medical Journal @bmj_latest

Widespread misconceptions about losing weight led Ruben Meerman and Andrew Brown at the University of New South Wales to calculate how we "lose weight."

Human fat cells store triglyceride, which consists of just three kinds of atoms; carbon, hydrogen and oxygen. Shedding unwanted fat requires unlocking the atoms in triglyceride molecules by a process known as oxidation.

By tracing every atom's pathway out of the body, the authors discovered that when 10 kg of fat are fully oxidised, 8.4 kg departs via the lungs as carbon dioxide (CO2). The remaining 1.6 kg becomes water (H2O).

Their analysis shows that the inhaled oxygen required for this metabolic process weighs nearly three times more than the fat being 'lost'. To completely oxidise 10 kg of human fat, 29 kg of oxygen must be inhaled producing a total of 28 kg of carbon dioxide and 11 kg of water.

"None of this biochemistry is new, but for unknown reasons it seems nobody has thought of performing these calculations before," say the authors. "The quantities make perfect sense but we were surprised by the numbers that popped out."

"These results show that the lungs are the primary excretory organ for weight loss," they add. "The water formed may be excreted in the urine, faeces, sweat, breath, tears, or other bodily fluids and is readily replenished."

"The exhaled carbon can only be replaced by eating food or consuming beverages such as milk, fruit juices or sugar-sweetened drinks," the authors say.

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Shed post-Christmas pounds just by breathing