Do foods gain calories when cooked?

I’ve been reading around that different foods gain calories when cooked. For example, a boiled egg contains fewer calories than a fried one, but I just assumed that the added calories were from butter or oil that people used to cook the eggs. Say you’re using a 0 calorie cooking spray, does the egg still gain calories when cooked?

from Bodybuilding.com Forums - Nutrition https://ift.tt/2Cmqyq6