Do you really need to worry about essential amino acids when you plan your daily meals?
Not really. Animal sources of protein such as meat, eggs, and dairy products are "complete proteins." That means that each protein found in an animal product contains each of the nine essential amino acids
Since most people get enough protein from their diet, protein deficiency is rare in developed countries.
In underdeveloped countries, protein deficiency is more common. Severe protein deficiency is called kwashiorkor. Children with kwashiorkor tend to have very thin arms and legs and large, distended bellies.
Lack of protein can cause growth failure, loss of muscle mass, a depressed immune system, lung problems, heart problems, and death.