How to Determine Protein Requirements

Your body needs protein to repair tissue and produce hormones and enzymes. However, you probably don't need as much protein as you think. Most Americans eat almost twice as much protein as they need, and athletes only need a little more protein than sedentary adults, according to MedlinePlus. Eating lots of protein doesn't help you build muscles - it just gets stored as fat. Eating too much protein can also strain your kidneys and increase calcium loss. You can calculate your protein requirements based on your weight.

Young adult male eating a meat meal (Image: Halfpoint/iStock/Getty Images)

Step 1

Multiply your weight by 0.45 to convert to kilograms. For example, if you weigh 150 pounds, you weigh about 68 kilograms.

Step 2

Multiply your weight in kilograms by 0.8 to determine how many grams of protein you need per day. For example, if you weigh 68 kilograms, you need about 54 grams of protein per day. Weight lifters need up to 1.8 grams per kilogram per day, while endurance athletes require up to 1.4 grams of protein per kilogram of body weight, notes the Iowa State University Extension.

Step 3

Multiply your daily caloric intake by 0.15 or 0.2 to estimate how many of your calories should come from protein. For example, if you eat 2,500 calories daily, you should get between 375 and 500 calories from protein.

Tip

If you tire easily, you may not get enough protein. Talk to your doctor if you aren't sure whether you're getting enough protein. Don't take protein supplements. Instead, get protein from lean meat, dairy and legumes.