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Why Calories Matter

Updated: Oct 21, 2021

Eat this. Do not eat that. That is very caloric. I can only eat low-calorie desserts.

We associate eating more calories with gaining weight and eating less with losing. But what is actually happening? In this blog I am going to do my best to explain the law of thermodynamics and why we change in regards to the number of calorie intake.

In order to understand how calories work, we first must find out what is calories.

Technically, a calorie is a unit for measuring energy. Or how much energy is needed to raise the temperature of one kg of water by 1 degree Celsius. Nutritionists like to call them kilocalories and use them to measure how much energy is stored in food molecule bonds and how much energy people burn by living.

In other words, we use calories to measure energy intake and energy expenditure.

Energy intake refers to all the food and drinks we ingest, measured in calories. Note that water does not contain any.

For example, one apple contains 52 calories. One pizza slice contains about 260 calories. A can of coke contains 150 calories. The amount of energy we are going to provide our body with if we ingest those foods.

Energy expenditure.

Calories are used to measure how much energy we use to perform activities, digest, and live. About 10 percent of the calories consumed are used for digestion. 20 percent are used for physical activity and 70 are used to support the normal function of organs and tissues.

I am going to spend a bit more time explaining better.

Those 70 percent refers to the basic metabolic rate or BMR. See, muscles and organs are metabolically active tissue. Meaning that even if you rest, your heart is still going to work and use calories, your organs are going to be working, so they will burn calories. If you imagine a worst-case scenario where someone is in a coma. Doctors are still going to feed that person with about 1600 to 2000 calories, just to keep the organs working.

When you add physical activity, you are going to increase the energy expenditure, again because muscles require energy or calories to be active. And this is on a daily basis.

Every single day we consume a certain number of calories and burn another. A constant cycle that stops only when we die.

Here comes:

The low of thermodynamics:

If calorie intake is greater than calorie expenditure – you gain weight. If calorie expenditure is greater than the calorie intake – you lose weight.

Now it can all be manipulated.

If you want to lose weight, you can choose to either intake fewer calories or expand more. If you want to gain weight. You can choose to either intake more or expand less.

Of course, our body is a complex system and there are factors such as food quality and, each body`s ability to utilize calories, age, medication, etc… However, it does work straightforward. It is low and in 99 % of the cases, if you just look at this as an equation, you can easily manipulate it.

It is worth mentioning that each food contains a different number of calories.

1 gram of protein contains 4 calories. 1 gram of carbohydrates contains 4 calories. 1 gram of fats is 9 calories. And the good old alcohol is 7 calories per gram. So next time you want to enjoy a whole bottle of wine, remember the calorie count. Joking of course. The goal is to make you aware. Not to judge your actions.

The calorie count is a very common activity these days. It is a requirement by most fitness professionals. There are apps that count the calorie intake for you and devices that measure the number of calories burnt. If you want to rely on them that is fine. They are great for providing baseline and average statistics so you can clearly see what you can manipulate or where are you at. I am just asking you to fully trust them or use them as a perfectly calibrated medical instrument, as they cannot be as accurate as they are stated.

My advice is to approach it slowly. Take one or ideally two weeks to track and write down each food you intake. Use some of the apps or simply ask Google for the calorie count on a specific food.

The reason for this is to gain knowledge of your baseline.

Let’s say you found out that every day you are averaging 2500 calories. One day it is 2300 another is 2600. Let’s assume that you want to lose weight. Look back at your food record and assess which foods can you eliminate from your diet. Imagine you had 3 times a piece of cake this week. That can average at around 300 calories per piece. Try to remove them for the next week or change them with fruits. That is going to remove in total 900 calories from the average for the week, or if you choose to change those pieces with fruits, you are going to decrease, let`s say with 450 calories. Well, congratulations. You just learned how to manipulate and use the low of thermodynamics to lose fats.

Another example. You want to gain weight. Track for two weeks. See that you are averaging at 2500 per day. Add a glass of milk twice per day or another small meal. That will add an additional 200 calories per day, which is going to average in more calories per weak

Do not make the mistake of drastically changing the calories. Manipulate slowly and let your body adapt. You cannot expect your body to lose a lot of weight and have no consequences for your health if you all of a sudden cut 1000 calories.

The low of thermodynamics is a useful tool but used incorrectly can be detrimental for the health of your body.


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