Where Does the Fat Go When We Lose It? Mathematics of Weight Loss

Hi! I am the author and founder of Old School Calisthenics

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I was always curious to find out the science-facts behind weight loss. Especially since there is a ton of bro-science in this area that keeps people hooked on magical diets and pills. In my quest for finding studies about it, I came across the scientist Ruben Meerman – most commonly known as The Surfing Scientist. He is an Australian scientist, educator, author, and public speaker.

I found a video of him on YouTube, a TEDx conference talk about the mathematics of weight loss. I watched the whole lecture and was so impressed by his explanation that I decided to post it on my blog.

If you saw his lecture, the conclusion is that we generally breathe out the burned fat into the mass of carbon dioxide. We don’t see it because it’s invisible and goes out in thin air.

body fat chemical formula

10 kilograms of fat, through complex biochemistry, becomes 8.4 kilograms of an invisible gas that you breathe out, says Ruben. So every time you’re doing some exercise, and your breathing rate goes up, you’re losing more weight than when you’re sitting down and not breathing as rapidly. The rest of the 1.6 kilograms will come out as water. It comes out in your sweat, urine or on the back door (there is still much to be discovered about this part).

In your effort to lose weight, try not to focus so much on counting your calorie intake. Just track roughly what you eat in a day, start eating a bit less than usual, and maybe clean up your nutrition. It’s not that calories don’t play a role too, but if you focus the energy on the things you have more control over, like increasing your metabolism, you should be able to achieve faster and more stable results.

You Need More Oxygen to Burn Calories

Oxygen Can Be Found in The Forest

Sciencedaily.com: “10 kilograms of fat requires 29 kilograms of oxygen to be inhaled and that this metabolic process produces 28 kilograms of carbon dioxide and 11 kilograms of water.”

You can’t sit and breathe more! It’s called hyperventilation and it doesn’t do too much good. But you can exercise more and eat less, boosting your oxygen consumption. According to an article found on ScienceNetLinks:

  • “Oxygen is used in your cells as the fuel that transforms the food you eat into energy
  • The air we breathe contains about 21% oxygen. This oxygen is brought into the lungs, where it is transported by the red blood cells to the entire body. Once the red blood cells return to the lungs, the “burnt” carbon dioxide is exhaled
  • The higher the oxygen intake, the better the cells work, and the lower the burden on our heart and blood circulatory system.
  • Regardless of how fit a person is, the body requires a certain amount of oxygen per kilogram (kg) body weight in order to perform a certain workload. This means that the heavier you are, the more oxygen you need. Let us say that you’re walking at a leisurely speed of 5 km/hr (about 3 miles per hour). If your body weight is 70 kg, you will need about 1 liter of oxygen per minute. If your body weight is 100 kg, you’ll need half as much again, or 1.5 liters/minute!
  • Gender also plays a role; women have around 30% less oxygen consumption than men. This is one of the main reasons that in general, it is a bit easier for males to lose weight or stay fit.
  • With a bit of fitness training and physical exercise, the oxygen intake and therefore the efficiency of the body can be increased by 20% or more. This means that all body functions will work better and easier.
  • The atmospheric pressure helps determine how dense the air is, and therefore what concentration of oxygen the air contains.”

For me, it makes more sense to train outdoors and especially where the concentration of oxygen is higher. I lost more weight and faster by running in the forest and on mountain trails compared to running on the streets of my city. I felt a significant improvement performance-wise because of the abundance of fresh air and also a great stimulus for my brain. Every time I finish a long run on the nearby mountains, I feel like I just meditated. I am more energized, fresh, and happy, even if my body gets beaten really badly.

Train Outdoors in Cold and Hot Temperatures


weight loss benefits in cold weather

According to New West Physicians: “…There is a fat-burning benefit to colder weather as it causes our body to shiver and activates reactions intrinsically within brown fat cells. As we are mammals and use fat cells to store energy, our bodies are designed to eventually utilize that fuel to regulate our core body temperature in cold temps. Therefore, we produce heat on our own through thermogenesis, which burns calories, turns white fat into brown, and results in decreasing body weight.”

It doesn’t matter how much you expose yourself to cold if your calorie intake continues to be way higher than what’s optimal (read about the advantages of training outdoors). Nonetheless, I agree that up to a certain extent, cold weather can help metabolism burn more calories. There is a lot of science behind the weight loss effects of brown fat. I don’t focus too much on this because I train outdoors all-year-round anyway.

We have pretty rough and cold winters in Romania. Temperatures can vary throughout the day from -3 to -15 Celsius. I often find it uncomfortable and it feels like I can’t train at my full capacity and strength. But it works! I really recommend you train outdoors when it’s cold. You obviously burn calories but also increases metabolism. There are also other amazing studies on the effects of cold on physical and mental health.

During summer, you once again burn a lot of calories because of the hot temperatures and the extra heat caused by hard training. The cardiovascular system works at high capacity. The heart is pumping at high beat rates, the blood vessels expand, and blood is circulating rapidly. It transports nutrients and the abundance of oxygen I talked about, and it does it very efficiently. The pulmonary circulation has to adapt to the demand, as well. As a consequence of all this, you eliminate the carbon dioxide and sweat out the fat.

Spot Reduction Doesn’t Exist!

According to Wikipedia: “Spot reduction refers to the claim that fat in a certain area of the body can be targeted for reduction through the exercise of specific muscles in that desired area. For example, exercising the abdominal muscles in an effort to lose weight in or around one’s midsection.”

Stubborn belly fat doesn’t exist either. Overeating, incorrect nourishment, insufficient training, the lack of it, or just inappropriate exercising can lead to accumulating fat. Match in every single
box, and over time, it can lead to obesity. Genes play no role. There is an exchange that happens in nature. It is inappropriate to say, but you eat energy from the sun. You gain size unless you burn it all out, and it requires some years to get fat; it doesn’t happen overnight. Losing weight is a reversible process, but it takes time. We measure fats energy in calories or kilo-Joules.

When calories-in versus calories-out equals 0, then you are maintaining the current weight. Therefore, approach the fat loss phenomenon as a whole, understanding the biochemistry behind (3 Simple Steps to Burn Fat)

Control Appetite!

Less and cleaner food to shred

According to New West Physicians: No more, no less, just the right amount. Hunger-regulating neurons in the brain can help encourage white fat to turn brown. This is achieved when eating just the right amount of food to satisfy hunger. Eating too few calories prevent white fat from turning brown. Overeating creates more white fat and interferes with brown fat’s ability to burn calories.”

I rigorously practice everything written here. It is one of the primary reasons I got so lean. I genuinely believe that if you want to max out the results and get fit, then you have to check every single box. Go halfway and you will diminish your chances of looking really good at the end of the journey. Losing weight takes a lot of time and effort as science shows. Practically, I needed a little over a full year to get rid of around 14 kilograms.

I hope you found my article comprehensive and useful at the same time. If that is the case, a share would be something I’d really appreciate. I wish you success in your weight loss journey. Come and find me if you need extra help or if you want to share your experience!

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