Final answer:
Eggs are considered an almost perfect source of protein because they contain all nine essential amino acids. Other complete proteins include meat, fish, dairy products, and soy for those following a vegan diet, with the combination of various plant proteins fulfilling protein needs.
Step-by-step explanation:
The quality of a protein source is determined by its completeness; a complete protein contains all nine essential amino acids. A food considered to be an almost perfect source of protein would be eggs, as they contain complete protein. Other excellent sources of complete proteins include meat, fish, and dairy products. Moreover, vegan options like soy also offer complete proteins. Foods with incomplete proteins, such as grains, nuts, and beans, can be combined to provide all essential amino acids needed by the body.
For those who do not consume meat or dairy, a combination of plant proteins is necessary to ensure a complete amino acid profile. Regular consumption of various plant-based proteins like legumes, nuts, and seeds can meet protein requirements. Protein powders, like whey and soy, are processed options that provide high concentrations of protein.