A Multivitamin in a Shell
If you're looking for a food source that delivers a lot of nutrients in a low-calorie package, it's hard to beat eggs. One egg provides 13 important nutrients including protein, iron, choline and vitamin A - most of them in the yolk. Eggs are also a source of lutein and zeaxanthin, two substances essential for healthy eyes that can also help prevent age-related vision problems. You get all this, plus small amounts of calcium, potassium, phosphorus, and vitamin D, for only 75 calories.

The Power of Protein
One egg packs more than 6 grams of protein, which is 12 percent of the Recommended Daily Value. Protein helps us stay full longer, thus decreasing the desire to overeat, which is why eggs make an excellent breakfast choice, especially for those trying to lose weight. A 2005 study published in the Journal of American College Nutrition found that eggs consumed at the start of the day helped its subjects feel satisfied and less likely to snack between meals.

The protein found in eggs is also considered to be high quality and more easily absorbed by the body. Protein is essential for building and repairing muscle during weight training, and eating eggs after working out can encourage muscles to recover quicker.