View larger image | A lack of nutrients, among other factors, can trigger cells to dine on themselves. The process begins with inhibition of a key protein. Then a curved double-membraned structure begins to form. It grows into what’s called an autophagosome and envelops cell innards in need of digestion. After an autophagosome fuses with a bag of enzymes called a lysosome, the contents get broken down and expelled for future use. Credit: Nicolle Rager Fuller