What is protein? Do you really know? Stop for a moment, and think about it. Is it a nutrient found in the piece of fish you ate last night? An ingredient in the Greek yogurt you enjoy so much? A component of tofu that helps you meet a nutrient requirement? While I’ll give you brownie points for those answers, protein is quite complex. It is the foundation of life.

There are approximately 20,000 to 25,000 different types of protein in the human body, and our genes provide the blueprint for building each one.

Think of protein as a train. Each car on the train is an amino acid, and they’re linked together by peptide bonds. Under a microscope, the “train” or strand of protein looks a bit like spaghetti, and the twenty different amino acids that form it determine its 3-D shape and specific function.

Some proteins provide structure in the form of ligaments, fingernails and hair; others aid digestion (i.e., stomach enzymes). We’re familiar with the proteins that allow movement (muscles), and still others play a part in our ability to see; the lenses of our eyes are crystalline protein.

While our body can make many amino acids from scratch, there are nine amino acids – called “essential amino acids” – which need to come from our diet. Often called high-quality protein, eggs, dairy, meat and soy all contain the perfect proportion of essential to non-essential amino acids. Protein from grains, vegetables and beans are of lower quality, making it very important for strict vegans to get protein from a variety of sources.

Many of my clients, friends and colleagues are vegan, but I prefer incorporating fish, poultry, cheese, milk and eggs into my diet for two reasons. The first being taste. To me, nothing is better than fresh cod baked en papillote with rosemary, lemon, cherry tomatoes, olive oil and French sea salt. I enjoy a tender, juicy roast chicken with herbed butter; a silky, runny cheese drizzled with honey for dessert, and milk and eggs incorporated into my whole wheat pancakes. Second, these foods broadly diversify healthy eating. Granted, if you don’t eat animal sources of protein due to ethical reasons, I respect that, but there’s no reason to eliminate these foods from your diet in a quest to be “healthier.”

Whether you eat beef or beans, your body digests protein the same the same way: Stomach acids break down the protein into amino acids (remember the train), and your body absorbs the amino acids via the small intestines. Then, your body gets to work, building the protein it needs – whether it’s hormones or antibodies. And yes. At this very moment, your body is at work, creating, destroying and recreating the very protein you need to thrive.

When it comes to requirements, most Americans get enough protein; though the quality can be debatable. Your goal should be to consume three ounces daily of high quality protein from sources low in saturated fats.

What are YOU making for dinner tonight?