Calories, Macronutrients, and the Energy Balance Equation

23.08.2017 |

Episode #1 of the course Fat loss for fitness enthusiasts by Theo Brenner-Roach


Welcome to the course and to Lesson 1.

Today, we will look at the core concepts of nutrition and cover the basics you’ll need to know to get the most out of the course.



You always hear people talking about calories when it comes to nutrition and weight manipulation, but what are they and why are they so important?

Calories are units of energy, and every day, you need a certain number of calories in order to fuel your body and any activity you do.

On a basic level, you need calories to survive.

They provide your body with the energy it needs to allow your brain to think, your heart to pump, and your lungs to breathe. Without this energy, you would sadly perish and die.

You expend this energy constantly, whether you’re lying down, sitting up, walking, talking, or exercising. This energy not only allows your body to maintain homeostasis, but it also fuels any exercise you do.

How this energy relates to your weight and manipulation of your weight brings us to the energy balance equation.

The energy balance equation is the relationship between the energy you put into your body and the energy you expend through living and activity.

The energy balance is essentially a reiteration of the law of thermodynamics, which states that energy is constant and cannot be created or destroyed; instead, it must be transferred between entities.

In our case, this transferal shows as changes in stored energy in the body.

The energy balance equation shows that:

• You will gain weight if your energy input is greater than your energy output.

• You will lose weight if your energy input is less than your energy output.

• You will neither gain nor lose weight if your energy input is equal to your energy output.

This clearly highlights the importance of calories for weight control, but where do we get this energy from?



Macronutrients, often called “macros” are the 3 main sources of energy in your diet, and they each play a different role in your body.

Protein. Protein plays an important role in building, repairing, and regenerating your body tissue and cells. It helps in the preservation of muscle mass and immune function and aids in the production of essential hormones and enzymes. It’s particularly important if you exercise regularly.

Fat. Fat is vital for the absorption of fat-soluble vitamins, maintenance of cell membranes, and hormone production. It can also be used as energy by the body.

Carbohydrate. Carbohydrate can be metabolized by the body very quickly and is the preferred source of energy. It aids in the proper function of your heart, brain, kidneys, and muscles. It can also be stored in your muscles and liver for use later and is important for intestinal health and digestion.


How Much Energy Do They Provide?

Each macronutrient has an amount of energy (calories) it provides per gram:

Protein has 4 calories per gram.

Fat has 9 calories per gram.

Carbohydrate has 4 calories per gram.


How Much Do You Need of Each?

Each macronutrient is needed in different amounts in the body when exercising.

While calorie intake is important for overall changes in body weight, macronutrients play a vital role in body composition.

Protein. To encourage muscle growth, you need sufficient protein intake, and recommendations for daily protein intake are 0.7-1 g per lbs (1.5-2.2 g per kg) of bodyweight. Aim for the higher side when “cutting” and the lower side when “bulking.”

Fat. To allow the production of important hormones and to provide satiety, you need adequate fat intake. Fat is also one of the most calorie-dense nutrients and is best kept to around 30% of daily intake. This is enough to get the benefits while leaving enough room for protein and carbohydrates.

Carbohydrate. To fuel your day-to-day activities, your brain, and your workouts, you need enough carbohydrates. They will make up the remaining calories in your daily intake once protein and fat have been accounted for.


Summing Up

Your calorie intake directly impacts your weight and can be manipulated to either lose, maintain, or gain weight.

These calories come from macronutrients, which are the 3 main food groups and can influence body composition.


Recommended book

Understanding Nutrition by Eleanor Noss Whitney, Sharon Rady Rolfes


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