The NITROGEN in our DNA, the CALCIUM in our teeth, the IRON in our blood, the CARBON in our apple pies were made in the interiors of collapsing stars. We are made of star stuff.
- Carl Sagan
November is rapidly coming to an end which can only means one thing: Christmas is around the corner! Fairy lights are popping up everywhere, decorations and Christmas trees have made their ways into shops and will soon arrive in our homes… and the gym is getting busier! It is not as bad as the new year affluence, when everybody’s new resolution seems to be “be healthier” or “workout more”, but still, there are a little bit more people than usual. It is as if people needed to lose weight for the holidays, as a sort of free pass to stuff their faces with delicious Christmas food, which will result in putting on even more weight than what they lost in preparation for the holidays. Guess that’s why gyms are at low risk of ever closing down: there will always be people wanting to lose weight!
Now that’s an interesting distinction: would you rather lose weight or lose fat? Those do words are often used interchangeably and yet...
When you lose weight, you are primarily losing water, fat and muscles, resulting in a decreased strength and a decreased fitness level. On top of that, because you lose water, your body is dehydrated, resulting in a reduced metabolism (the thing that runs in the background making sure everything works efficiently in your body… 20% of which occurs in your muscles) and your organs shrink. Sure, sound like a good thing if your stomach shrinks, reducing your level of hunger and thus the amount of food you feel like eating. Not so great when your brain start losing some of its functionality as a results of quick, uncontrolled fat lost (yup, your brain is partially made up of fat). If that’s not enough, weight lost leads to early aging: you lose more motor (movement and muscle) and cognitive (brain stuff) abilities than you should given your age. Yay…
When you lose fat, you improve the general composition of your body with a better muscle/fat ratio, you increase your metabolism (without losing muscles and with less fat to deal with, it becomes more efficient), and you delay the aging of your body and of your brain. By losing fat, you also protect your heart from fat deposits in your arteries (the blood vessels delivering blood from the heart to the rest of the body); too many deposits will reduce the diameter of your arteries and reduce the amount of blood that can be delivered to the body at one time. And finally, you have a better fitness level as you lose fat. Easy choice, right? It is true that losing fat doesn’t mean you will fit in that size 4 dress/jeans you have been dreaming to wear for the last 3 years, but it means you are going to have a well-defined strong body, fitting in size 6 clothes, with curves in the right places (or revealing all your muscles and showing your hip bones for the gentlemen reading this post and having no interest in fitting in size 4 dress). I know which I’ll chose any day.
Which leads us to an interesting question: where does the fat goes when you lose fat? It doesn’t magically disappear (I wish…) so something as to become of all the fat we’re losing. The most common idea, shared by a lot of very clever people that study human biology for a very long time (doctors, dieticians, personal trainers among others), believe that when someone lose weight (i.e., fat), it turns into energy/heat needed to fuel your body. And that what I learned in my biology classes. When you’re training (not just cardio training, but also weight, HIIT…), you want to reach the point when your body turns to anaerobic ways to create energy. Those are the ways that do not rely on the oxygen you breathe and uses your fat deposits to create the energy your muscles need to function, resulting in you “burning” fat away. Turns out it is not the whole story… not at all.
In order to create energy, we need a source: excess carbs and proteins (fats and sugars) coming from our diet, converted into big molecules and stored in the body in the fat deposits. These big molecules cannot circulate in the body: once in the fat deposits, they stay there… unless they are broken down into smaller molecules that can move around and be send where needed to create energy. Yes because fat deposits are not an energy-production centre, that would be too easy, so the source needs to be sent to the energy-production centres (like the muscles) to contribute to the creation of energy. And the way the fat deposits reduce in size, i.e. the way we lose fat, is when the big molecules are broken down into smaller molecules. All those molecules (carbs, proteins, fat, sugars, whatever you call them) are made of carbon (C), oxygen (O), and hydrogen (H). The energy our body used is not made of those. And that where the “problem” lies.
See, in the 18th century, a French chemist named Lavoisier announced the law of conservation of mass, that goes like that: in the universe, nothing is created or lost, everything is transformed. For example, if we have 6C + 12H + 18O, the only possible things you can do with those molecules will be using all of them: 6 CO2 + 2 H2O OR C6H12O6 (that’s a sugar) + 6 O2. Which means that our fat deposits made of carbon (C), oxygen (O), and hydrogen (H) cannot create energy if the energy our body used to function is not made of those! So, here we are again: where does the fat go?
You breathe it out. Yup, you read that right. It goes like that: a molecule of fat (C55H104O6) is broken down thanks to oxygen (78 O2; just trust me on this one, let’s keep things simple), leading to the formation of carbon dioxide (55 CO2), water (52 H2O), and residual energy that will contribute to the creation of our main energy source. If you count the number of C, H, and O before/after transformation, it is the same. Nothing got lost, everything was transformed. The carbon dioxide is released into the atmosphere as you breathe out during exercising, and you sweat the rest out. Most of our fat is transformed into gas (84%), and the rest is turned into water (16%). I must admit, it makes perfect sense, but it still blew my mind.
Careful though: we do not lose weight/fat just by breathing – that would be way too easy. So next time you want to shed some extra pounds, do not inhale/exhale more in the hope it will melt your fat away. You risk hyperventilating, which can have a lot of bad consequences for you (and mainly your brain). However, next time you're exercising, don’t forget to breathe in and out to the fullest to help bring oxygen to your muscles and body and reject that fat. Breathing just got more interesting.
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