The calories in one egg depends on its size and how it is cooked, but a small raw or boiled egg can contain about 55 calories. However, a medium egg that is hard-boiled and without additives can have 70 calories.
Frying an egg can raise the number of calories to between 90 to 95 calories. Similarly, scrambled eggs that contain milk can be over 100 calories. Most of the calories associated with eggs come from the yolk. For example, a cooked large egg yolk has 55 calories while cooking the white from this same egg has 18 calories.
Eggs are a good source of protein, iron, vitamins and nutrients such as lutein and zeaxanthin, which are carotenoids that may be beneficial in lowering the risk of macular degeneration. Eggs also contain choline, which may be good for memory.