Fat Loss 101 Part 1: Calories and Metabolism

Today you officially start Day 1. Good job!

You are now part of a community who is hungry to change their bodies for whatever goal they have.

Do you already have a goal? Maybe you are not doing The 1 Thing That People Fail to Do. Check it out first if you haven’t and come back here.

Done? Great!

So you have a plan but…

You do not know where to start with the nitty-gritty.

How does this all come together? 

Let’s take a little lecture. I’m going to try to make this as interesting as possible. Stick with me. The knowledge you are about to receive is something that is widely followed by all fitness advocates around the world. Some of them ask you to pay for it. I’m giving it to you for free.

Let’s define terms first:

A calorie is a unit of energy. In terms of your body, calories measure the amount of energy your body uses to function. Calories come from… you guessed it. Calories come from the food you eat. Calories keep you alive.

the guy with infinite calories to burn
This guy has infinite calories  to burn. Get it?


Now how do we know how much the body uses up exactly and how can we use this information to for our goals?

Enter two concepts: BMR and TDEE.

BMR is Basal Metabolic Rate. This is simply the number of calories you burn while resting. Of course, you still burn calories while you sleep. Your organs need to function 24/7: heart keeps beating, lungs help you breathe, your digestive tract digests food from last night’s buffet… You’re never at a standstill.

BMR is affected by many factors: age, sex, height, and weight. So your BMR will be different from another person’s BMR who is older or heavier or is an opposite sex.

human body factory
It never closes. When it does, you know what that means. *skull*


But as much as we want to sleep all day, we don’t. Sleep is important but life happens. So what happens now that we move and do things? What happens to the number of calories our body needs? You guessed it again: the calorie demands increase.

 This increase in calorie demand comprises our TDEE or Total Daily Energy Expenditure. The TDEE is the number of calories our body needs taking into account the daily activities that we do from standing up to your bed in the morning to laying on it again in the evening.

The TDEE includes all physical and mental exertion (yes, you burn calories while thinking) that you experience during a normal day. The TDEE has different levels depending on your daily activity type. Each level has a corresponding factor that you need to multiply to your BMR  so you can get your maintenance calories.


In order to know your maintenance calories (the calories you need to maintain your weight now), you need to get your BMR first and multiply by the factor corresponding to your daily activity.

Sedentary (desk job, almost zero exercise) – 1.2

Lightly active (desk job but moves around, 2-3x a week exercise) – 1.375

Moderately Active (always standing on the job, 3-5x a week exercise) – 1.55

Very Active (trainers, athletes, physically demanding jobs like laborers) – 1.725


The number that you get is the number of calories you need to sustain your daily activities and maintain your current weight.

For example, my BMR is 1400 calories. My activity level is 1.375 since I have a desk job but I train 3x a week. That’s (1400*1.375). My maintenance calories or TDEE is 1925 calories.

This simply means that if I eat 1925 calories every day and continue my daily activities, my current weight will stay the same as well. Cool?

Try this BMR calculator and get your TDEE after. You might be pleasantly surprised.

Calories in versus Calories Out

You now know that the BMR and TDEE of each person are unique. There may be similarities at some point but no human is ever the complete mirror image of another. Even twins have different BMRs and TDEEs.

Who are you between these two?
Who are you between these two?


The very first thing that I learned about the concept of nutrition of calories in versus calories out. It was simple but problematic:

  • If you want to lose fat, eat fewer calories than you can burn.
  • If you want to gain muscle, eat more calories than you can burn.

See, it is problematic because the tendency when you live by this concept is people now see any type of food as enemies (because they contain calories) and any type of physical activity is a fat burning, even sunbathing /facepalm. And the truth is: People either severely undereat or overeat. It’s one or the other.

The end result? Depressed people who are overtrained, burned out and worst of all, only lost 1-2 lbs. and gain it back double when they give up. Another bad result would be eating disorders like anorexia or bulimia where every calorie becomes an obsession that at the end of the day, you decide not to eat anything at all or eat everything and purge everything out by puking.

This is the reason why we now have a stigma about weight loss: It takes up too much effort and in the end, you gain it all back.

The Consequence of Not Eating While Dieting: Meet Cortisol

Your BMR pretty much controls the normal regulatory function of your body. This includes your metabolism and the production of hormones.

Any disturbance to the balance, the whole system collapses. The beauty of the human body is it’s quick to adapt. It will always try to maintain balance or homeostasis. But of course, there will be consequences.

Let this be put out there: Any type of dieting or exercise is a form of stress to our body. Read that two more times and move on.

When our body is stressed, it produces the hormone cortisol. It’s the stress hormone. This hormone wreaks havoc on our metabolism and slows it down in an effort to conserve what you are currently putting in (i.e. food) and the type of activity you are doing. Your body is trying to achieve balance while you are consciously making an effort to offset this balance. NOT GOOD!

Your body starts to convert the pinches of food you eat into fat so it can be used for long-term energy to sustain your biological processes. May it be veggies or rice, cortisol acts as a checkpoint as if to say…



When your body produces a lot of cortisol, you destroy your metabolism. Your hormones get crazy and at some point, your body starts to beg you to do something about it because it’s having a really hard time…

Ladies and gentlemen, meet your old friend: stress eating. Consciously knowing and acknowledging that you are stress eating though, is another story. That, my friends, is called a lack of discipline and this topic is for another post.

Anyway, it’s a domino effect. I don’t think you need more words to explain the end results of this cycle.

So what’s the point, Nick?

 The point of this blog post is to educate you on what goes on inside your body so you will know what to do on the outside.

The main takeaway: Know your BMR and TDEE so you can have a rough guideline of how much you should be eating in a day, regardless if you are a couch potato or an active athlete.

Knowing your BMR and TDEE  will help you sustain your activities and keep your body happy.


If you found this article helpful, please share. I’d really appreciate it!

Check out Part 2 here –> Fat Loss 101 Part 2: Why Cardio Is NOT The Way to Fat Loss





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