Why is protein an important part of the fitness puzzle?

May 24, 2014

Q: I know that including protein in my diet is important for getting results from my workouts, but can you shed a little more light on what protein is, why it's important and what are the best sources to get results?

A: One of the most important things you can do to build a lean, muscular and healthy body is include a variety of quality proteins in your diet. Here’s why.

What is protein?
Protein is the key component in building, repairing and maintaining lean muscle, and it is the best way to get essential nutrients called amino acids needed by the body. There are 20 amino acids needed, and the body is capable of producing 11 of them, but to get the other nine, you must eat a balanced diet with a variety of different foods containing quality proteins.

Why is it important?

In addition to building bigger muscles, protein also helps promote healthy skin. As you get older, you begin to lose valuable collagen, so your skin begins to lose its elasticity and wrinkles begin to appear, but eating enough protein can help solve this problem. Certain proteins contain amino acids such as L-Lysine and L-Proline that can boost collagen stores, keeping your skin firm and tight.

Protein can also help you control your hunger and lose weight. A recent study published in the American Journal of Clinical Nutrition concluded that a 15 percent increase in dietary protein could result in a significant amount of weight loss and can curb hunger. Participants of the study naturally consumed fewer calories and lost weight, and reported feeling satisfied and less hungry. Several other studies have come to similar conclusions, leading experts to believe that protein promotes more stable insulin levels and sends signals to the brain telling it the body is full.

Lean proteins promote muscle growth and suppress appetite, causing weight loss, better cholesterol, lower blood pressure and a healthier heart. They can also help regulate blood sugar levels, reducing insulin spikes and preventing obesity and metabolic syndrome.

What foods contain quality protein?

Quality protein can be found in lean animal meat such as chicken, turkey, beef and eggs, but some people choose to supplement with protein powders made from whey and casein to get enough protein in their diet.

Fish is what I like to call a two-for-one special because it contains two key components needed to build muscle and burn fat - protein and omega 3 fats. Fish such as tuna, tilapia and salmon contain high amounts of protein as well as important amino acids needed for the growth and repair of muscles.

Beef has often been misunderstood and considered unhealthy, because most people eat the worst cuts containing large amounts of saturated fats, but few people realize lean steak can be an excellent source of protein. Flank steak, top round and sirloin can provide 25 grams of high-quality protein per 4 oz. serving as well as vitamin B12 for cell repair, brain function and blood health.

Eggs are considered an excellent protein source because they contain nine essential amino acids, making them a great choice for muscle repair and growth. They're also one of the few foods that contain naturally occurring vitamin D and have been linked to the prevention of breast cancer in women.

Whey protein is a byproduct of making cheese from milk. It is usually found in supplements and premade drinks. It provides an abundant source of amino acids as well as being low in cholesterol, sugar, sodium and carbs, making it a great value and a popular meal replacement. Whey protein is particularly valuable as a pre- and post-workout meal because of its ability to be quickly absorbed by the body and enter the bloodstream.

Casein is also made from milk, but it is different from whey protein because it's slowly digested, releasing a steady stream of amino acids. This means that it is a muscle-sparing protein that can be used to slow muscle breakdown and preserve lean tissue. Since the average person sleeps approximately eight hours, casein can be the perfect pre-bedtime meal. To add casein to your diet, you can simply drink a glass of milk, but an 8 oz. serving will only have about 6 grams, so it makes much more sense to buy a casein supplement that will contain roughly 20 grams per serving.

  • Chris Antonio is a personal trainer and former world-class weightlifter. He has been lifting for more than 20 years and has trained a wide variety of clients ranging from All-American athletes to the average person trying to get into shape. To send a question to the Ask the Trainer column, email Chris at or check out