Is it safe to eat only 600 calories a day?

Answer 1

No, not at all. Most human bodies need about 800 to 1,000 calories a day just to survive, at the minimum. (Breathing, heart beating, simple movements.) When people do active things, ranging from walking to playing in sports, the body requires more calories to have enough energy to do so. Eating too few calories deprives the body of nutrients and can harm many organ and systems in the body.