Nutritionists used to warn against eating eggs for health. Today, the opposite is true. Eggs are a good source of protein, with under 100 calories. One large hard-boiled egg has about 71 calories, with over 6 grams of protein and 5 grams of fat.

Here’s how the different parts compare:

Hard-boiled egg white:

Hard-boiled egg yolk:

“Eggs are considered the purest source of protein and the best bang for your buck, nutrition-wise,” says Emily Tills, MS, RDN, CDN, a registered dietitian nutritionist in Rochester, New York. “They have a wide mix of fat-soluble and water-soluble vitamins.”

Eggs contain several essential vitamins as well as certain minerals including calcium and iron. They’re one of the few food sources of vitamin D, one of those fat-soluble vitamins. Vitamin D requires fat to be absorbed, which the egg yolk provides. Egg protein also contains all essential amino acids.

The caveat? Cholesterol in the yolk. Although experts now believe dietary cholesterol has little effect on blood cholesterol, one hard-boiled egg contains 186 mg, or 71 percent of what the FDA recommends daily.

The science shows that otherwise healthy individuals can enjoy a couple of eggs each day while the American Heart Association suggests one egg (or two egg whites) daily.