Fat loss is one of the most common goals in exercise and fitness. Every day on social media and out in the world you will see people bragging about losing weight, articles and articles giving you the latest “quickest way to weight loss” tips. So we all want to shed the pounds and lose the fat right? So where does the fat go? Well, just like Felicia, it’s going places; but not where you might expect.
As the study reports, 84% of energy expenditure is through the lungs, 16% through water. The lungs conveniently is also where energy production begins (through the inhalation of oxygen). To simplify things a bit for us all, all living animals need oxygen in some form or another to survive. This is because oxygen is a crucial component toward energy production. Your body utilizes oxygen to break down fat, carb and protein molecules to formulate Adenosine Triposphate (ATP) which is the source of raw energy the body uses to function. Your body is doing this all throughout the day and night, utilizing fat as it’s primary source of energy to maintain daily functions (walking, breathing, pooping, eating, etc.). This process is called Aerobic Oxidation and it is the same system you might use during long, endurance cardio (running a marathon, triathlon etc.). During endurance exercise, the Aerobic Oxidation goes into a zone known as “steady state” which is when the body consumes the amount of oxygen necessary to sustain that intensity level for a seemingly infinite amount of time (depending of course on your fitness level).
A third energy system which is even faster in response than Glycolysis stores ATP molecules directly for immediate use, this is known as the Phosphagen System.
When you start any kind of formal exercise activity, all 3 energy systems activate together, however only one system is the dominant energy source at any given moment while the other two continue to operate in the background. 0-30 seconds is the Phosphagen system (high intensity exercise), 30 seconds – 2 minutes is Glycolysis (moderate to high intensity exercise) and anything over 2 minutes is primarily Aerobic Oxidation (low to moderate intensity exercise). The only system that utilizes oxygen directly is Aerobic Oxidation. While it can get a bit technical, the Aerobic Oxidation system creates ATP from two different sources, fat and glycogen (carbs). Piggy backing off of Glycolysis it utilizes oxygen to take up Hydrogen atoms from the Electron Transport Chain and it turns into H2O (water). When these molecules are exchanged, the resulting effect is what creates ATP, the energy source of the body. This process is known as Oxidative Phosphorylation (spelled right on the first try!)
So you might be wondering, during short, intense bursts of exercises only lasting a couple of seconds… why are you breathing so hard? Such as running up a flight of stairs, power lifting, etc. During those intense bursts, you are utilizing either the Phosphagen system and/or Glycolysis which don’t utilize oxygen to generate ATP. However, Aerobic Oxidation is still occurring in the background and immediately following the activity starts to ramp up production not only to continue producing energy should the activity continue, but to restore and replenish the reserves you just utilized. This is known as Excessive Post Oxygen Consumption. It can last anywhere from a few minutes to several hours following intense exercise (depending on how long and how hard you were working). You can train this process to become quicker and more efficient as you train and subsequently become stronger and fitter in your selected task.
Which finally brings us back to our original question. Where does the fat go?
Don’t be fooled though, you can’t burn more fat simply by breathing hard, sadly it doesn’t work like that. Remember it’s all about increasing the demand for energy production! Therefore to burn more fat and lose more weight, you will need to expend more energy through daily exercise and physical activity. In addition, keeping more control on how many calories you consume (fat, carbs, proteins, alcohol) to keep you from consuming and storing more energy than you are subsequently utilizing.
Scientifically speaking, the best way to enact long term, healthy weight loss is a combination of increased exercise and physical activity coupled with healthy eating habits and moderation. You can burn calories through aerobic fitness (cardio) and strength training effectively to enhance weight loss. So get to work!