Protein can be found in muscle, bone, skin, hair, and virtually every other body part or tissue. It is the building block of enzymes, which power many chemical reactions, as well as haemoglobin, which transports oxygen in your blood. At least 10,000 different proteins contribute to your identity and keep you that way.
Protein is composed of over twenty basic building blocks known as amino acids. Because we cannot store amino acids, our bodies produce them in two ways: from scratch or by modifying others. The essential amino acids, which include histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine, must be obtained from food.
What Protein Do I Need?
The National Academy of Medicine recommends that adults get a minimum of 0.8 grams of protein for every kilogramme of body weight per day, or just over 7 grammes for every 20 pounds of body weight. 
For a 140-pound person, that means about 50 grammes of protein each day.
For a 200-pound person, that means about 70 grammes of protein each day.
The National Academy of Medicine also sets a wide range for acceptable protein intake—anywhere from 10% to 35% of calories each day. Aside from that, there is little solid evidence on the optimal amount of protein in the diet or the healthiest target for protein calories. In an analysis conducted at Harvard among more than 130,000 men and women who were followed for up to 32 years, the percentage of calories from total protein intake was not associated with overall mortality or specific causes of death. The source of protein, on the other hand, was critical.
What exactly are “complete” proteins, and how much do I require?
It is important to note that millions of people around the world, particularly children, do not get enough protein due to food insecurity. Protein deficiency and malnutrition can cause everything from growth failure and muscle mass loss to decreased immunity, heart and respiratory system weakness, and death.
However, deficiency is uncommon in healthy adults in the United States and most other developed countries due to an abundance of protein-rich plant and animal-based foods. In fact, many in the U.S. are consuming more than enough protein, especially from animal-based foods.
It’s All About the Protein “Package”
When we eat foods for protein, we also eat everything that comes alongside it: the different fats, fibre, sodium, and more. It’s this protein “package” that’s likely to make a difference for health.
The table below shows a sample of food “packages” sorted by protein content, alongside a range of components that come with it.