It is true that human beings can't exist without taking any nutrition, and the meaning of eating food has a lot of physiological elements, but it is also influenced deeply by the cultural environment where you live. When you eat food, you think many things, you have various feelings. And sometimes you are affected by the person with whom you have a meal and sometimes you are influenced by the culture and society. It is obvious that good scent or taste make people want food. Such actions are different from the physical and I can't live 4 physiological appetite.
Human society has a lot of cultural meanings or discourses of eating or tasting in food.
And you can divide food into many kinds of pair categories. And sometimes sight and touch senses decide our selection. That is how you select the food you eat, and the experiences and your memory divide food into two categories, good or bad. There are some things that human beings cannot feel like eating even if they include much nutrition. You whet our appetite only for the thing that it is considered that it is good to eat and taste in your culture.