How Much Protein Do You Need?
Susan Bowerman, MS, RD, CSSD
In nutrition lingo, protein is a macronutrient. Macro, meaning “large” because compared to the amounts of vitamins or minerals we need to eat, we need relatively large amounts of protein in the diet. Protein is vital to virtually every cell in the body, and our bodies are constantly assembling, breaking down and using proteins. Therefore it’s critical that we eat enough protein to replace what’s being used.
How much protein do you need every day? How do you know how much you’re eating? There are established guidelines for how many grams of protein the average man, woman or child should be eating, and these recommendations are set at levels to meet the basic needs of most people.
But body sizes and body composition can vary a lot from person to person, which means that protein needs may vary a lot, too. It stands to reason, for example, that the amount of protein needed by a 150 pound, male bank teller who doesn’t get much exercise is going to be less than that needed by a 220 pound bodybuilder. So how can you figure out how much protein your particular body needs?
A fairly easy way to estimate individual protein needs is from your current body weight. It’s not a perfect method, because it doesn’t take into account how much muscle mass you have, but it does at least account for differences in body size. If you take your body weight in pounds and divide it in half, the number you get is about the minimum amount of protein, in grams, that you should eat each day. So a woman who weighs 140 pounds should aim for at least 70 grams of protein a day; a 200 pound man should shoot for at least 100. Those who are trying to build up muscle would want to take in about 50% more.
Most of us get about 2/3 of our protein from meat, fish, poultry, milk products and eggs. Vegetarians can meet their protein needs from high quality plant sources like soy and other beans, along with the protein supplied from other plant foods like nuts, whole grains and vegetables.
To estimate how much you’re eating, start with this: every three ounces of cooked meat, fish or poultry will give you about 20 grams of protein. From there, you can use food labels to determine how much you’re getting from foods like beans, nuts, grains, eggs and dairy products. You’ll be surprised at how quickly you can meet your target. If you need 100 grams of protein a day, a protein smoothie made with milk in the morning, a bowl of lentil soup at lunch and 6 ounces of fish at dinner will rack up about 75 grams right there. Factor in a carton of Greek yogurt for a snack and some brown rice with dinner and you’ll have no trouble hitting your target by the end of the day.