We all need protein from our diet every day for optimal health and particularly for better endurance. This is true at all ages, for males and females, regardless of your sport. Larger body frames and those performing more extreme sports may need more protein. Growing children also need higher amounts of protein for development. But once optimal body size is attained and growth stabilizes, there is still a significant and continuous need for protein. We tend to think of protein needs as being higher in weight lifters and bodybuilders but endurance athletes have similar requirements, perhaps even greater.

What’s the best protein food? Eggs.

In addition to helping build muscles, protein is necessary for many other activities:

• Protein is necessary to make enzymes important for balancing fats, digestion, and hundreds of other metabolic functions.

• Protein is essential for maintaining neurotransmitters—the chemical messengers used for communication by the brain and nervous system, and especially the gut.

• Protein is a key element for building new cells in bones, organs, glands, and elsewhere all throughout the body—and for the rest of your life.

• Oxygen, fats, vitamins, hormones, and other compounds are regulated and transported throughout the body with the help of protein.

• Protein is necessary to make natural antibodies for the immune system.

• Protein contains key amino acids for health. For example, cysteine is necessary for the body to make its most powerful antioxidant, glutathione; glutamine is used as energy to fuel the intestine’s villi for nutrient absorption.

• Protein is important for the production of glucagon in relation to controlling insulin, blood sugar, and other key areas of metabolism.

Eggs are a near perfect protein food all wrapped up in one single cell. Eggs contain the most complete and highest protein rating of any food. Two eggs contain more than twelve grams of protein, just over half in the white and the rest in the yolk. In addition, eggs contain many essential nutrients, including significant amounts of vitamins A, D, E, B1, B2, B6, folic acid, and especially vitamin B12. Eggs also contain important minerals including calcium, magnesium, potassium, zinc, and iron. Choline and biotin, also important for energy and regulation of stress, are contained in large amounts in eggs. Most of these nutrients are found in the yolk.

Ounce per ounce, eggs are also your best protein food buy with hardly any waste. And, with so many ways of cooking them, eggs are delicious and quick to prepare. For most people, eggs can be part of a healthy food plan; I eat several whole eggs a day.

The fat in egg yolks is nearly a perfect balance, containing mostly monounsaturated fats and about 36 percent saturated fat. Additionally, egg yolks contain linoleic and linolenic acids—both essential fats for optimal health and fitness.

While most people love the taste of eggs, many are still concerned about eating them because of cholesterol. Perhaps the greatest misconception about cholesterol is that eating foods containing it significantly raises levels in the blood. In truth, most studies have shown that eating cholesterol does not alone substantially increase blood-cholesterol levels. Moreover, some studies show that not eating cholesterol can prompt your body to make more—and that eating eggs can actually improve your cholesterol numbers!

Other dietary factors can influence cholesterol more than eating cholesterol. Excess dietary carbohydrates can raise the more dangerous LDL cholesterol levels. This is due to excess triglycerides from carbohydrates producing more, smaller, denser LDL particles, which are even more likely to clog arteries.

Eating too much saturated fat can also raise LDL and total cholesterol levels. The worst offenders may be dairy foods such as butter, cream, cheese, and milk. Red meat such as beef, while it does contain saturated fat, can actually improve cholesterol levels. This is partly because, just as in eggs, about half the fat in beef is monounsaturated. Grass-fed beef has the best balance of fats compared to most beef, which is corn fed. In addition, much of the saturated fat in beef is stearic acid, a fatty acid that won’t raise cholesterol and may actually help reduce it. (The fat in cocoa butter also contains high amounts of stearic acid.)

After decades of medical research, studies have never linked egg consumption to heart disease. Stephen Kritchevsky, PhD, director of the J. Paul Sticht Center on Aging at Wake Forest University, states, “People should feel secure with the knowledge that the [medical] literature shows regular egg consumption does not have a measurable impact on heart disease risk for healthy adults. In fact, many countries with high egg consumption are notable for low rates of heart disease.”

Eggs are only as healthy as the hens that lay them, since the nutritional make-up of eggs, especially the fat, depends upon what the chickens eat. For this reason you should avoid run-of-the-mill grocery-store eggs that have been produced in chicken factories. Unfortunately this includes most eggs on the market. The healthiest eggs come from organic, free-range hens. Even better: buy eggs from a local farmer who lets chickens eat healthy, wild food and organic feed. Local free-range usually means that the hens are allowed to roam where they can eat bugs and vegetable matter, yielding more nutritious eggs. So-called omega-3 eggs come from chickens fed flax seeds. Often these hens are neither free-range nor certified organic and are still housed in very crowded hen factories.

The best protein supplement for use in smoothies and other recipes is egg white powder. It’s the most natural and least processed of all the protein powders. (If you use egg-white powder in a blender, you must include a small amount of fat otherwise it will create a large volume of foam—great for meringue but not for smoothies.)

Regular training requires great nutrition, with protein being a key part of your diet. Eggs provide a quick and easy way to make a meal that’s inexpensive and delicious, and will help fulfill your body’s protein needs.

A long-time fixture in triathlon, running and many other sports, Dr. Philip Maffetone coached many of the world’s best—including Mark Allen, Mike Pigg, and Colleen Cannon. He's the author or more than a dozen books on sports, fitness and health. His latest book is "The Big Book of Endurance Training and Racing," with a foreword by Mark Allen. His website is www.philmaffetone.com