Macronutrients: Calculating Your Proteins, Fats & Carbs

macronutrients-macros-fats-proteins-carbs-carbohydrate-squareLet’s figure out your macronutrients!  In our post Calories: How Many Do I Need? we outlined four steps to help you determine your Total Daily Energy Expenditure (TDEE).  Your TDEE is the total number of calories you need on a daily basis.  Knowing your TDEE is a great first step in taking control of your diet.  Now we want dig a bit deeper and explore how you can allocate the calories of your TDEE.

In this post we will first look at a few definitions and the roles of macronutrients in your diet.  Then, we will outline how to estimate your protein, fat and carbohydrate daily requirements.  We also provide a link to a simple tool that automates these calculations for you.

We hope that this post provides you with the knowledge and tools you need to make informed decisions about the composition of your diet.

Some Basic Macronutrient Knowledge

Macronutrients are the nutrients that provide us with the energy (measured in calories) needed by our bodies for growth, metabolism and other functions.  The prefix “macro” means large; macronutrients are needed in large quantities in contrast to micronutrients (vitamins and minerals).

Proteins, fats and carbohydrates make up the group of macronutrients.  Let us take a moment to briefly look at each of these macronutrients.

Carbohydrates: These are a major source of energy for our bodies and are stored in our muscles and liver for later use.  Foods that contain large amounts of carbohydrates include fruits, grains (rice, oats, barley, etc) and roots (potatoes, yams, carrots, etc).  Carbohydrates provide 4 Calories of energy per gram.

macronutrients-protein-meat-beans-nuts-poultry-fish-dairy-squareProteins:  Our bodies use proteins to grow tissue and muscle, repair organs and to create hormones and enzymes; proteins are also used for energy when carbohydrates are unavailable.  Foods that contain high levels of protein include poultry, fish, beans, diary, nuts and legumes. Proteins provide 4 Calories of energy per gram.

Fats:  In order to absorb vitamins, our bodies need fats.  Foods that contain a high percentage of fat include cooking oils, butter, nuts and cheese.  Of the three macronutrients, fats contain the highest number of calories per gram; fats provide 9 Calories of energy per gram.

The Institute of Medicine (IOM) in its report on dietary intake for energy recommends ranges for proteins, fats and carbohydrates.   The following table summarizes IOM’s recommended ranges for adults.  You should note that some diets do not abide by these ranges for various reasons. For example, there is evidence that diets containing higher levels of protein (higher than 35%) are more effective for weight-loss4.  Think of these ranges as a very rough estimate of what your macronutrient distribution should look like.

Macronutrients Ranges Table

Table 1. IOM’s Macronutrient Ranges Recommendations

Calculating Your Macronutrients

Now that we have introduced the basics of macronutrients, you can proceed with calculating your macronutrients using the following four (4) steps.

Step 1 – TDEE: Determine your Total Daily Energy Expenditure (TDEE).  Check out our post Calories: How Many Do I Need? if you need help determining your TDEE.

Step 2 – Proteins:  Estimate your required protein intake by choosing a percentage from the range in the table above (Table 1) and multiplying it by your TDEE.  Alternatively, determine how many grams of protein per pound of body weight you need based on your physical activity level.  The following chart from Bodybuilding.com recommends protein levels based on physical activity level/lifestyle.

Calculating Macronutrients - Protein Requirements

Table 2. Proteins requirement based on physical activity level

Example Calculation: An adult weighing 150 lbs who exercises recreationally, based on Table 2 above, would need 0.75 grams of protein per pound of body weight.

Daily Protein Intake (in grams) = 0.75 grams per lbs x 150 lbs = 112.5 grams of protein

Next, convert your protein intake from grams to Calories; to do this conversion, multiply your daily protein intake (in grams) by 4.

Example Calculation:  Using the result in the previous example

Daily Protein Intake (in Calories) = 112.5 grams of protein x 4 Calories per gram = 450 Calories from protein

macronutrients-macros-fats-oils-nuts-butter-squareStep 3 – Fats:  Decide what percentage of your diet will be fat; select a percentage between 15% and 35%.  Multiply this percentage by your TDEE to get your fat intake in Calories.  Convert this value from Calories to grams by dividing it by 9; 1 gram of fat provides 9 Calories.

Example Calculation: With a TDEE of 2,475 Calories and a desired fat composition of 20%

Daily Fat Intake (in Calories) = 20% x 2,475 Calories = 495 Calories from fat
Daily Fat Intake (in grams) = 495 Calories ÷ 9 Calories per gram = 55 grams of fat

Step 4 – Carbohydrates:  Subtract your fat and protein intake values (in Calories) from your TDEE to calculate your required carbohydrate intake.

Example Calculation: Using the values from the examples in steps 2 and 3:

Daily Carbohydrate Intake (in Calories) = TDEE – (Protein Intake + Fat Intake) = 2,475 Calories – (495 + 450) Calories = 1,530 Calories

 Convert the carbohydrate intake from Calories to grams by dividing by 4; carbohydrates provide 4 Calories per gram.

Daily Carbohydrate Intake (in grams) = 1,530 Calories ÷ 4 Calories per gram = 382.5 grams

Let a Machine Do the Math!

Now, that was fun! But if you’re uninterested in manually performing the calculations above, you can consider using the Free Dieting Macronutrient Calorie Counter.  This tool lets you use pre-defined ratios for or define your own.

This post provided you with a general idea of how to calculate your daily macronutrient requirements.  In later posts we will take an even deeper look into each macronutrient and discuss the various differences between the subcategories of each macronutrient.  For example, there are various types of fats–polyunsaturated, monounsaturated, trans and saturated fats–and our bodies treat each of these differently.

 

REFERENCES

1. Nutrition Source, Harvard School of Public Health: https://www.hsph.harvard.edu/nutritionsource/
2. https://www.hsph.harvard.edu/nutritionsource/carbohydrates/
3. https://fnic.nal.usda.gov/food-composition
4. Sacks FM, Bray GA, Carey VJ, et al. Comparison of weight-loss diets with different compositions of fat, protein, and carbohydrates. N Engl J Med. 2009;360:859-73
5.What Is the Minimum Percentage of Fat That Should Be Consumed by Adults? Retrieved 1/11/2016 from http://healthyeating.sfgate.com/minimum-percentage-fat-should-consumed-adults-2893.html

 

 

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