This question is similar to whether instant noodles are harmful. How to judge the value of a food to human beings depends on whether its ingredients meet human needs. Pizza is mainly made of flour with fruits, vegetables and meat on it. We provide carbohydrates, vitamins and protein respectively, but because pizza will also add dairy products with high fat content such as cheese, it may make us fat, which should be its shortcoming. But we can't ignore the carbohydrates, protein and vitamins provided by pizza. Everything should be treated dialectically.