Lifestyle: Nutrition

How to Calculate Your Protein Needs According to a Dietitian

How to Calculate Protein Needs How to Calculate Protein Needs

By Shannan Bergtholdt, MS Ed, RD

Every cell and tissue in our body requires protein. It is one of the three main nutrients along with carbohydrates and fat, and yet many of us are still unsure how much protein to eat.  

The amount of protein we need per day depends primarily on your weight and physical activity level. Protein needs can vary during periods of illness, pregnancy, lactation, and for older adults.  For the purposes of this article, we’ll focus solely on the protein needs of adults.   

Learning how to calculate your protein needs doesn’t need to be complicated. In fact, you can do it in two simple steps outlined below.  

Daily Protein Needs 

There are two ways to approach calculating your protein needs. One way is to determine protein as a percent of daily calories. Another way is to determine how many grams of protein are needed per day and then determine how they fit into daily calories.  

1. Percent Calories from Protein  

The Food and Nutrition Board of the Institute of Medicine (IOM) recommends that 10 to 35% of total daily calories should come from protein. These generalized percentages will work for a majority of active adults.  

Knowing a general percentage is helpful, but protein needs should be based on a person’s body weight, not a calorie amount. This is why the IOM also recommends that protein intake should be between 1.2 to 1.8 grams of protein per kilogram per day, depending on activity level. 

2. Grams of Protein per Day 

The current Recommended Dietary Allowance (RDA) is slightly different from the IOM, which is where it might get confusing when trying to figure out your protein needs. The RDA for protein is 0.8 to 1.0 grams per kilogram per day for adults. There is a growing consensus that the RDA might be adequate for sedentary adults to prevent protein deficiency but doesn’t reflect the amount of protein needed for daily physical activity or for optimal health. 

Protein Needs for Exercise 

A Joint Position Statement between the American College of Sports Medicine and the Academy of Nutrition and Dietetics states that a protein intake range of 1.2 to 2.0 grams per day is needed to support exercise, muscle repair, and growth.   

Higher protein levels of 2.4 grams per kilogram for healthy weight individuals, may be needed during periods of particularly high intensity training and for adults wanting muscle gain.   

Overweight adults have a lower recommended protein intake of 1.2 to 1.5 grams of protein per day. This amount should help preserve muscle and lean tissue as the individual loses weight. 

Calculate Your Protein Needs in 2 Steps 

Use your current body weight to find your daily protein needs in two steps.  

Step 1: Calculate Your Body Weight in Kilograms 

Take your body weight in pounds and divide by 2.2 to get your body weight in kilograms.   

Example 150 pounds ÷ 2.2 = 68.2 kilograms of body weight 

Step 2: Multiply Your Body Weight by Protein Range 

Multiply your body weight in kilograms by the appropriate protein range for your activity level.  

A summary of the recommended protein ranges are:  

  • Normal weight sedentary adults: 1.2 to 1.8 grams per day 

  • Normal weight active adults: 1.2 to 2.0 grams per day 

  • Normal weight active adults for muscle gain: 1.2 to 2.4 grams per day 

  • Overweight adults: 1.2 to 1.5 grams per day 

Example: The formula for a normal weight 150-pound adult would look like this.  

68.2 x 1.2 to 2.0 = 82 to 136 grams of protein per day 

Next Steps 

Once you’ve determined how many grams of protein you need per day, you can translate grams of protein into ounces on your plate. Protein is found in a variety of foods including lean meats, poultry, eggs, seafood, beans, nuts, seeds, lentils, and peas.  

Many animal-based protein foods offer as many as 7 grams of protein per 1-ounce serving. Take a look at the protein content of the foods in your pantry, you may find protein in unexpected items.  


References 
[1] Exercise and the Institute of Medicine Recommendations for Nutrition (Accessed Nov 30, 2022) https://journals.lww.com/acsm-csmr/Fulltext/2005/08000/Exercise_and_the_Institute_of_Medicine.3.aspx 
[2] Dietary Reference Intakes, Chapter 10 (Accessed Nov 30, 2022) https://nap.nationalacademies.org/read/10490/chapter/12 
[3] Is the Optimal Level of Protein Intake for Older Adults Greater Than the Recommended Dietary Allowance? (Accessed Nov 30, 2022) 
https://academic.oup.com/biomedgerontology/article/68/6/677/873141 
[4] American College of Sports Medicine Joint Position Statement. (Accessed Nov 30, 2022) https://journals.lww.com/acsm-msse/Fulltext/2016/03000/Nutrition_and_Athletic_Performance.25.aspx 
[5] Protein, amino acids and obesity treatment (Accessed Nov 30, 2022) 
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7455583/ 
[6] Dietary Guidelines for Americans 2020 (Accessed Nov 30, 2022) https://www.dietaryguidelines.gov/sites/default/files/2020-12/Dietary_Guidelines_for_Americans_2020-2025.pdf 
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