Biochemists have found that as people lose weight, fat can be both burned off and simply breathed out of the body.
However, the researchers warn people that exercise is still required to be able to keep themselves slim, as hyperventilating with an increased breathing rate by itself will not allow people to lose weight.
The team of researchers from Australia, which were able to trace the route of fat as it leaves the body in the microscopic level as atoms, published their findings in the British Medical Journal's Christmas edition.
According to the study, breaking down fat causes chemical bonds to break, which release heat and the fuel required for the human muscles to function. However, the atoms that make up the fat remain, with much of these particles leaving the human body through the person's lungs in the form of carbon dioxide.
Fat acquired from food is stored within the body inside cells named adipocytes, as a compound named triglyceride. Triglyceride, made up of carbon, oxygen and hydrogen atoms, breaks down into one-fifth water (H2O) and four-fifths carbon dioxide (CO2).
The water created when fat is broken down can be released through bodily fluids such as sweat and urine, and be replenished when the person drinks water. The carbon dioxide, however, is only replaced by consuming food or dinking certain beverages like fruit juice.
"None of this biochemistry is new, but for unknown reasons it seems nobody has thought of performing these calculations before," said Andrew Brown and Ruben Meerman. Brown and Meerman, from The University of New South Wales in Australia, are the co-authors of the study.
The study also reveals that it is actually the person's lungs that are the main excretory organ for losing weight.
The study's estimates state that the average person exhales 200 grams of carbon daily, with roughly one-third of that amount exhaled during sleeping.
If a person replaces an hour's worth of rest for exercise with moderate intensity like jogging, an additional 40 grams of carbon is removed from the body.
To be able to keep losing weight, people will have to strike a balance on the food that they consume and the carbon dioxide that they burn off and exhale.
The saying "eat less, move more" is confirmed by the findings of the study, said the researchers, as weight loss requires people to unlock the carbon that is stored within fat cells.
Duane Mellor from the British Dietetics Association compared the burning off of fat to the fuel in a car's engine. The engine burns the fuel, creating heat and driving movement, but waste is also created and released.
"The atoms left after breaking down fat for energy are like the exhaust fumes," Mellor said.
