Macronutrients 201: How They Affect the Body

Article written by Colton Pettit, certified personal trainer.

When planning a proper diet, there are 3 primary factors you need to consider. These factors are known as Macronutrients (aka macros).

The three macros are:

→ Carbohydrates → Fats

→ Proteins.

Each of these macros is responsible for different processes in the body.

Because of this, the quantity and quality you should eat of each macronutrient will be different.

Let's dive into each one and how it affects your body and goals!

CARBOHYDRATES

Carbohydrates, aka "carbs," are the body's primary energy source.

When you consume carbs, the body breaks them down into glucose, which is then absorbed by your cells and used for energy.

If more carbs are consumed than an individual needs, they become stored in your muscles as glycogen.

This means that to have enough energy for your workout, your body will either use glucose in the bloodstream from recently consumed carbs or use glycogen from past carbs.

This is why the most important time to eat carbohydrates is between 1 to 2 hours before a workout.

That way, your body will have plenty of energy to push hard during your workout!

Examples of healthy carbohydrates:

• Whole grains (quinoa, brown rice, oats, whole wheat bread/pasta)

• Legumes (lentils, chickpeas, black beans)

• Fruits (berries, apples, bananas, oranges)

• Vegetables (sweet potatoes, carrots, leafy greens, bell peppers)

• Nuts & seeds (chia seeds, flaxseeds)

PROTEINS

Proteins are the building blocks of muscle.

Without them, your body would be incapable of building new muscle or holding onto the muscle you already have.

Protein is actually an overarching term used for 20 different types of amino acids, 9 of which are essential.

When consuming proteins, it’s important to ensure they contain all nine essential amino acids because the body cannot make them on its own. To make sure foods have all nine essential amino acids, make sure they are labeled as a “complete protein.”

Complete proteins include:

→ any meats (chicken, fish, beef, etc.)

→ dairy products (cottage cheese, milk, etc.)

→ most protein powders.

Examples of healthy protein sources:

→ Lean meats (chicken breast, turkey, lean beef)

→ Fish (salmon, tuna, cod)

→ Eggs

→ Dairy (Greek yogurt, cottage cheese)

You can get complete protein sources that are vegan as well, but they are much harder to find.

Simply be on the lookout for non-animal-based protein sources that are labeled as "complete proteins" or sources like these!

Vegan-friendly protein sources:

→ Plant-based proteins (tofu, tempeh, edamame)

→ Legumes (lentils, black beans, chickpeas)

→ Quinoa (a complete protein with all 9 essential amino acids)→ Vegan Protein Powders (pea, rice, hemp, or soy protein)

→ Nut Butter (almond, peanut, cashew—but in moderation due to higher fat content)

FATS

For a long time, doctors and nutritionists viewed fats as bad.

However, more research found that fats are essential for proper hormone function in both men and women.

When consuming fats, more than any other macronutrient, it’s important to pick sources from healthy whole foods.

Certain fats are necessary for the body to function, such as:

→ Omega 3

→ monounsaturated fats

→ polyunsaturated fats.

Great sources of healthy fats include:

→ salmon or mackerel

→ avocados

→ olive oil & avocado oil

→ nuts (almonds, walnuts, cashews)

→ eggs

→ dark chocolate (85% or higher cocoa)

NOTE: Not all fats have to come from these healthy sources!

Other types of fat can be very bad for your health like:

→ trans fats

→ saturated fats.

Small amounts of saturated fats are okay to consume.

But consuming them in moderation and trying to get at least 80% of fats from healthy sources will help keep your heart and body working properly.

HOW MUCH DO I NEED?

Now that you understand what each macronutrient does, the last thing you need to know is how much of each of them to have.

PROTEIN

Protein is the easiest to know.

To gain muscle, you should try to get 0.7-1g of protein per pound of body weight each day.

FAT

Fats are a little more difficult. For men, you should try to keep about 20% of your daily caloric consumption from fats.

Women require a little more fat to keep their hormones working properly, so they should keep about 25%- 30% of daily calories from fat.

CARBOHYDRATES

Carbohydrates are the only macronutrient your body can function without, so we will calculate them last.

Once we know how many fats and proteins we need, we will calculate how many calories we have left before we reach our daily total. All of our remaining calories will come from carbohydrates.

Following this model will allow you to get all of the nutrients you need!

EXAMPLE

Here’s an example macronutrient breakdown for a 2000-calorie diet using these guidelines.

Step 1: Determine Protein Needs

For this example, our client weighs 150 pounds and wants to build muscle.

They aim for 0.7–1g of protein per pound of body weight.

• Protein intake: 150 grams (using 1g per pound for simplicity)

• Calories from protein: 150 grams × 4 kilocalories per gram = 600 kcal

Step 2: Determine Fat Needs

For this example, let's assume the person is male and needs 20% of their calories from fat.

• Calories from fat: 2000 × 20% = 400 kcal

• Grams of fat: 400 kilocalories ÷ 9 kilocalories per gram = 44 grams of fat

(As mentioned above, females need 25%; they would aim for 500 kcal or ~56g of fat.)

Step 3: Determine Carbohydrate Needs

Now, we calculate how many calories remain for carbohydrates.

• Total calories used so far:

  • Protein: 600 kilocalories

  • Fat: 400 kilocalories

  • Remaining calories: 2000 - (600 + 400) = 1000 kilocalories

• Convert calories to grams of carbs:

  • 1000 kilocalories ÷ 4 kilocalories per gram = 250 grams of carbs

Final Macro Breakdown for a 2000-Calorie Diet (Male Example)

✅ Protein: 150g (600 kcal)

✅ Fats: 44g (400 kcal)

✅ Carbs: 250g (1000 kcal)

This breakdown provides a balanced muscle-building approach while maintaining proper fat intake!

CONCLUSION

Every macronutrient is important, and ensuring you get them from quality sources is just as important.

Getting enough carbs, fats, and proteins will energize you and give your body all the necessary ingredients to reach your goals.

Often, poor macronutrient ratios can be the reason people don’t reach their goals, but now you can know for sure that this won’t be the case for you!

LOOKING FOR MORE HELP?

Still a little confused about how to reach your goals with the help of macronutrients?

Chat with a Certified Personal Trainer today!