进食又称吃、食、吃饭，是动物为了保持体能和生命所进行之有序的摄入营养和能量的过程，是动物的一种本能。所有动物都必须进食其他生物才得以生存。《古诗十九首》中的诗句：“思君令人老，岁月忽已晚。弃捐勿复道，努力加餐饭。”《红楼梦》句：“凡歇落处，每用吃饭”；费尔巴哈说：“心中有情，首中有思，必先腹中有物”

进食由肚子饿所触发，通过一些生理及心理作用引起食欲，促使动物去找寻食物以进食。若进食失调便会造成许多疾病，如厌食症、暴食症、营养不良等。

不同动物的进食方式不一样，以人类来说，进食乃指将食物放入口内，然后加以咀嚼、吞咽的一系列过程。食草动物如牛、马进食植物，肉食动物如狮子、老虎进食其他动物，而包括人类和猪在内的杂食动物则两者皆吃。

Eating (also known as consuming) is the ingestion of food, typically to provide a heterotrophic organism with energy and to allow for growth. Animals and other heterotrophs must eat in order to survive — carnivores eat other animals, herbivores eat plants, omnivores consume a mixture of both plant and animal matter, and detritivores eat detritus. Fungi digest organic matter outside of their bodies as opposed to animals that digest their food inside their bodies. For humans, eating is an activity of daily living. Some individuals may limit their amount of nutritional intake. This may be a result of a lifestyle choice, due to hunger or famine, as part of a diet or as religious fasting.