The Fate of Fat
By Claire Williams, Biology, 2019
It’s the beginning of a new year. Everyone has been hitting the gym and burning some fat. Or have they? No, this isn’t a question of whether or not people are upholding their New Year’s resolutions. Rather, it is a question of the process at play. Is the fat really “burning”? According to a study published at the end of 2014 by Ruben Meerman and Andrew J Brown, fat loss is misunderstood by many health professionals and the general public.
According to a survey of family doctors, dieticians, and personal trainers, approximately 65 percent of family doctors believe that fat is converted to energy or heat. Approximately 15 percent believed that it left the body as feces, became muscle, or exited as sweat or urine. Only approximately 10 percent of professionals surveyed answered correctly, all of whom were dieticians.
In order to address the mystery of the disappearing fat, it is important to examine what really happens when we spend an hour on the elliptical, attempting to shape up and slim down. In order to understand this, a look must be taken at the biochemical structure of triglycerides and their metabolism.
First, it is important to define what exactly this “fat” is that many spend hours trying to eliminate. According to Meerman, unneeded ingested carbohydrate, protein, and fat are converted to triglycerides and then stored within lipid droplets in fat cells. “Burning fat” targets existing triglycerides, as people attempt to break down and metabolize these storage units. The formula for an average triglyceride was published in a study done in 1960, by Hirsch and Colleagues, yielding C55H104O6.
The aim is thus to eradicate C 55H 104 O 6. How this occurs on the molecular level is the next question poised in the article. According to Meerman, the chemical formula for the metabolism of triglycerides is as follows:
C55H104O6 + 78O2→ 55CO2+ 52H2O + Energy
When triglycerides are broken down, they combine with inhaled oxygen to form carbon dioxide and water which is accompanied by a release of energy. The next step for Meerman was to determine in what ratio carbon dioxide and oxygen are formed. By following each atom from its existence within the triglyceride molecule to its exit from the body, Meerman was able to determine the ratios in which these atoms depart as either carbon dioxide or water. The carbon atoms depart the body as CO2, and hydrogen atoms depart as H2O. The final step of the process is to determine the fate of the six remaining oxygen atoms.
Due to the exchange of oxygen atoms between carbon dioxide and body water via carbonic acid, the six oxygen atoms will be shared between water and carbon dioxide in the ratio that they exist in the molecules. Therefore, four will be destined to form CO2 while two will be converted to H2O.
Finally, Meerman concluded that the mass of a triglyceride that is converted to carbon dioxide is the mass of carbon atoms plus the mass of four of the oxygen atoms. What remains, then, is the mass of the hydrogen atoms plus the mass of the remaining two oxygen atoms. After calculating these figures, Meerman arrived at the conclusion that 84 percent of a triglyceride’s mass is destined to become carbon dioxide, while the remaining 16 percent is converted to water.
These calculations lead to the notion that the lungs are the primary organ of weight loss. The amount of weight loss that is possible is limited by the body’s rate of exhalation of carbon. According to Meerman, doing aerobic exercise for just one hour allows an additional 39 grams of carbon to be exhaled.
This leads us to an interesting question posed by some readers in response to the Meerman article. In a review of Meerman’s article by Richard Knox, the following question was addressed. With everyone attempting to lose weight, is the extra carbon we are exhaling adding to our carbon footprint as a human race? It is a well known fact that carbon dioxide production is directly related to climate change. Therefore, the assumption that follows is that if a large percent of the population is aiming to deplete extra carbon, this would negatively impact the environment. Luckily, the answer is no. According to the Energy Information Association, 98 percent of CO2 in the atmosphere comes directly from the use of fossil fuels. Unlocking the carbon that has been stored deep underground is the issue at hand. The carbon that exists within triglycerides will be released into the atmosphere in one way or another, which is not the case for fossil fuels.
Therefore, unfortunately, environmental awareness is not an excuse for breaking your New Year’s resolutions. Keep metabolizing those triglycerides.
