(uncountable) Protein is a natural substances in food such as meat, milk, and beans.
Dr. Lecter told me that if I ate more protein, it would help me get bigger and stronger.
He told me that foods like milk, eggs, fish, and beans have a lot of protein in them.
(countable) A protein is a molecule that all cells need to live. Plants, animals, and humans all need proteins. Proteins are made of many of the most important things we need to live.
When a person's body makes proteins that are the wrong shape, it can cause problems like Alzheimer's Disease.
