The world is captivated with fad diets and weight loss, yet few people know how a kilogram of fat can go off the scale. Surprisingly, even the doctors, dieticians, and coaches we interviewed share this astonishing gap in their knowledge in this area.
By far the most common misconception is that fat is converted into energy. The problem with this theory is that it violates the law of conservation of matter, which all chemical reactions obey. For some interviewees, the fat turns into muscle, which is impossible, and others assumed that it escapes through the colon.
Only one person gave us the correct answer and was able to explain how weight loss works. So if it’s not for energy, muscle, or the toilet, where does the fat go?
The Truth about Fat Metabolism
The right answer is that fat is converted into carbon dioxide and water (which provides energy). You breathe out the carbon dioxide, and the water mixes in your circulation until it is lost as urine or sweat.
If you give up 5 kilos of fat, about 4 kilos go out through the lungs and the remaining 1 kilo turns into water. In other words, approximately all of the weight we lose is expired.
For information, here is the scientific formula for weight loss:
C 55 H 104 O 6 + 78 O2 → 55 CO2 + 52 H2O + energy
This may amaze a lot of people, but in fact, almost everything we eat comes out of the lungs.
Every carbohydrate you digest and almost all fat is converted into carbon dioxide and water. The same goes for alcohol.
Proteins divide the same fate, except for a small part that turns into urea and other substances, which you excrete in your urine.
The only things in food that get to your undigested, intact colon are dietary fiber.
Everything you swallow is absorbed into your blood and organs, and after that, it won’t go anywhere until you vaporize it.
For information, ■■■■■ are made up of 75 to 85% water and the rest (dry matter) is made up of dietary fibers (cellulose among others), intestinal secretions, mucus, bacteria, and ■■■■ cells.
Incoming kilograms and outgoing kilograms
We’ve all heard it said once that a calorie is a calorie, but beware, because energy is a confusing concept.
It would be a lot less mysterious why we gain or lose weight if we kept track of all kilograms, not just those enigmatic kilojoules or calories.
On average, we consume 3.55 kg of food and drink each day. Of that number, 430 grams are solid macronutrients, 17 grams are fiber, and the remaining 3.11 kg are water.
What is not indicated is that we breathe more than 660 grams of oxygen, and this figure is equally important for the waistline.
If you place 3.55 kg of food and water in your body, plus 660 grams of oxygen, then 4.2 kg of things must come out, otherwise, you will gain weight. And if you want to lose weight, more than 4.21 kg will have to be eradicated.
The 430 grams of carbohydrate, fat, protein, and alcohol that most people consume each day will produce exactly
- 770 grams of carbon dioxide (CO 2)
- 290 grams of water (H 2 O)
- And almost 31 grams of urea and other solids eliminated as urine
The resting metabolism of a person weighing on average 75 kg (the rate at which the body uses energy when the person is not moving) generated about 590 grams of carbon dioxide per day. No pill or potion you can purchase will increase that number, despite the bold claims you may have heard.
The good news is, you exhale 200 grams of carbon dioxide while you sleep every night, so you’ve already exhaled a quarter of your daily target before you even get out of bed.
Eat less, breath out more!
So if fat converts into carbon dioxide, can just breathing more make you lose weight?
Unfortunately no.
Breathing in and out more than essential is called hyperventilation and will only cause dizziness or even fainting.
The only way to intentionally increase the quantity of carbon dioxide the body generates is to move your muscles.
More good news. Just getting up and getting dressed more than doubles your metabolic rate. In other words, if you just tried on all of your outfits for 24 hours, you would exhale over 1200 grams of carbon dioxide.
More genuinely, going for a walk triples your metabolic rate, just like cooking, vacuuming, or sweeping.
Metabolizing 100g of fat utilizes 290g of oxygen and generates 280g of carbon dioxide plus 110g of water. The food you eat cannot change these numbers.
Therefore, to lose 100g of fat, you will need to exhale 280g of carbon dioxide in addition to what you will produce by vaporizing all your food, no matter what you eat.
Any diet that gives less “fuel” than what you burn will do, but with so many misunderstandings about how weight loss works, few of us know why.