the word 食 can be verb and noun. when it's a verb, it means "to eat". Eg. 廢寢忘食 He worked so hard that he forgot to eat. But verbal speaking we use "吃" instead of "食". Eg. Let's grab a bite.我們去吃點什麼吧 when it's a noun, it means "food". Usually we said "食物". It refer to all kinds of food. the word 菜 is noun. It can mean " course" . Eg. We had three courses this lunch. 今天午餐我們吃了三道菜 It can mean "vegetables" Eg. There are different kinds of vegetables in market. 市場賣各式各樣的菜

食 is a character of verb and noun, but 菜 is noun sole. If 食 is used in noun by a character, the common noun incorporate 食物(food)、美食(delicious food) 、食材(material of cuisine). In terms of 菜, it is a path of 食物, because rice, bread, cake, dumpling is not 菜.

生活中我们用菜比较多，食是吃东西的意思，如:食不言，意思是吃东西的时候不要说话；食物，可以吃的东西

谢谢 again!

''What is the difference between X and Y?'' 請問X和Y有什麼不同？ By the way, "請問" means "ask a question politely". You can put it in front of the questions when you're talking to teachers, strangers, elderly people. When we talk to friends, we usually don't use "請問".