Proteins Nutrition Facts

Protein is one of the basic building blocks of the human body, making up about 16 percent of our total body weight. Muscle, hair, skin, and connective tissue are mainly made up of protein. Additionally, protein plays a major role in all of the cells and most of the fluids in our bodies. Many of your important chemicals like enzymes, hormones, neurotransmitters, and even DNA are at least partially made up of protein. Although the human body is good at “recycling” protein, you use up protein constantly, so it is important to continually replace it.

Food Sources of Protein

Protein is found in both plant and animal sources of food. Animal sources, such as beef, poultry, pork, fish, and wild game are high in protein. So are sausages, bacon, and deli meats. Major plant sources include nuts and seeds, with lesser amounts in grains.

Vegetarian vs. Non-Vegetarian Protein Sources: What’s the Difference?

All proteins are made up of smaller units called amino acids. Our bodies can manufacture most of the needed amino acids, but nine of them must come from our diets. Animal proteins such as meat, eggs, and dairy products contain all the essential amino acids so they’re known as complete proteins.

Plant proteins are also made up of amino acids, but it’s rare for a plant protein to contain all the essential amino acids, so they’re referred to as incomplete proteins.

People who eat animal proteins don’t have to worry about whether or not they’re getting enough essential amino acids as long as they consume enough protein every day. Vegetarians who eat eggs or dairy products don’t have much to worry about either. Vegans, who only eat plant-based foods, may have to pay attention to their protein sources to make sure they get enough essential amino acids every day. This can be done by eating ant proteins such as soy, quinoa, or chia, which are complete proteins, or consuming complementary proteins every day.

What Are Complementary Proteins?

Complementary proteins are plant proteins that when combined provide all of the essential amino acids. For example, grains and legumes are complementary because grains are extremely low in an amino acid called lysine but they contain plenty of tryptophan, methionine, and cysteine. Legumes, on the other hand, are high in lysine but low in those other amino acids.

The grains and legumes complement each other and when you consume both, vegans can get all the amino acid they need. Nuts or seeds and legumes are also complementary proteins. These proteins don’t’ need to be consumed at the same meal, just some time during the same day.

Health Benefits of Protein

For the most part, eating protein-rich foods supplies the raw materials your body needs to maintain tissues, organs, and for all the functions mentioned earlier. Eating protein can also help you manage your weight because it takes longer to digest a protein-rich meal so you’ll feel full longer (just be sure to watch your calories, too).

Some protein foods have additional health benefits based on other things. Fish, such as salmon, tuna, herring, and trout, is high in protein and also omega-3 fatty acids that are essential for health. Legumes are high in protein and they’re high in fiber and contain phytochemicals that may have health benefits.

Risks of Protein Deficiency

Unlike fat and glucose, our body has little capacity to store protein. If we were to stop eating protein, our body would start to break down muscle for its needs. Protein deficiency is rare in developed countries, however it can happen if someone is not eating enough food every day.

Risk of Eating Too Much Protein

This is an important topic for people on diets that are higher in protein than usual. In a review of the research, the National Academy of Sciences reported that the only known danger from high-protein diets is for individuals with kidney disease. After careful study, they recommend that 10 percent to 35 percent of daily calories come from protein. They also point out that increased protein could be helpful in treating obesity. There is also accumulating evidence that extra protein may help prevent osteoporosis.

However, eating large amounts of protein can lead to dehydration, even in elite athletes. So if you follow a high protein diet, it’s important to drink extra water.

Extra protein can be broken down into glucose in a process called gluconeogenesis. On low-carb diets, this happens continually. One benefit of obtaining glucose from protein is that it is absorbed into the bloodstream very slowly, so it doesn’t cause a rapid blood sugar increase. However, some people with diabetes do find that too much protein causes an excessive blood sugar rise, and low-carbers sometimes find that as time goes on they do better with a moderate protein intake right than eating large amounts of protein.

How Much Protein Do You Need?

Protein needs depend on age, size, and activity level. The standard method used by nutritionists to estimate the minimum daily protein requirement is to multiply your body weight in kilograms by 0.8, or weight in pounds by 0.37. This is the number of grams of protein that should be the daily minimum.

According to this method, a person weighing 150 pounds should eat about 55 grams of protein per day, a 200-pound person should get 74 grams, and a 250-pound person should eat 92 grams.

An easier way to judge protein needs: ounce equivalents.

The USDA has general protein intake recommendations based on ‘ounce equivalents’ that may be easier to understand. These recommendations are made on age and sex and are good for people who are are moderately active:

  • Children 2 – 3 years old: 2 ounce equivalents per day
  • Children 4 – 8 years old: 4 ounce equivalents per day
  • Children 9 – 13 years old: 5 ounce equivalents per day
  • Girls 14 – 18 years old: 5 ounce equivalents per day
  • Boys 14 – 18 years old: 6 ounce equivalents per day
  • Women 19 – 30 years old: 5 1/2 ounce equivalents per day
  • Women 31 years and older: 5 ounce equivalents per day
  • Men 19 – 30 years old: 6 1/2 ounce equivalents per day
  • Men 31 – 50 years old: 6 ounce equivalents per day
  • Men 51 years and older: 5 1/2 ounce equivalents per day

What Counts as an Ounce Equivalent?

The amount of protein varies from food to food, so here’s a handy chart to help you know what equals one ounce equivalent of protein. These foods are the mainstays of the USDA’s ChooseMyPlate protein group:

  • 1 ounce of meat, poultry, fish or game
  • 1/4 cup cooked legumes
  • 1 egg
  • 1 tablespoon of peanut butter,
  • 1/2 ounce of nuts (out of the shell)
  • 1/2 ounce of seeds

Other foods such as milk, cheese, grains and even veggies contain smaller amounts of protein.

Do Athletes Need More Protein?

Yes. People engaging in endurance exercise (such as long distance running) or heavy resistive exercise (such as body building) can benefit from additional protein in their diets. The current recommendation is for these athletes to consume 1.2 to 1.7 grams of protein per day for each kilogram of body weight.

But what if you’re a casual athlete or just trying to build more muscle? You may need just a little more protein in your diet. Work with your doctor or dietitian to help figure out the right amount for you.

Do Pregnant Women Need More Protein?

Yes. The Institute of Medicine recommends that the minimum protein consumption for pregnant women be about 10 grams per day more than usual, though this is not as crucial in the first half of the pregnancy.

Shouldn’t Protein Intake Be a Percentage of Total Calories?

Quite a few programs and nutritionists quote percentage of calories, usually in the range of 10 percent to 20 percent, as a way to figure out how much protein a person needs to consume daily. This is a rough estimate of a person's minimum protein needs. It works because typically, larger and more active people need more calories, so the more calories they need, the more protein they will get.

Where this falls down is when people are eating diets that are lower in calories for any reason, conscious or not. People who are ill or losing weight, for example, do not need less protein just because they are eating fewer calories, so anyone on a weight loss diet should not go by the "percent of calories method" for calculating protein needs.

Incorporating Protein into Your Diet

Foods that are high in protein can be healthful or they can be loaded with calories, fat, sodium or even hidden added sugars. Here are a few tips to get enough protein into your day without ruining your diet:

  • Serve scrambled eggs and spinach for breakfast.
  • Choose turkey bacon or sausages that are lower in fat. Better yet, look for brands with reduced sodium.
  • Add seeds or chopped nuts to a green salad or on top of a veggie side dish
  • Snack on a handful of almonds and berries or a small to medium sized apple.
  • Buy lean cuts of meat and avoid heavy creamy sauces that can add a lot of extra calories. Serve your meat with lots of dark green and colorful veggies.
  • Eat more fish, but avoid breaded fish. Choose baked or poached fish instead.
  • Serve baked or roasted chicken instead of fried chicken.
  • Make a stir-fry with pieces of chicken and fresh veggies.
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Article Sources
  • Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients) (2005), Food and Nutrition Board, National Academy of Sciences.
  • Lemon, PWR. (1996). “Is increased dietary protein necessary or beneficial for individuals with a physically active lifestyle?” Nutrition Review 54:S169-S175.
  • Nutrition During Pregnancy: Part II. Institute of Medicine. (1990)
  • United States Department of Agriculture. “All About the Protein Foods Group.”