Benjamin Franklin quoted “Our necessities never equal our wants” and it’s well said. We always strive to solve this equation and we end up doing Need < Want.
The synonyms are always treated as one & same by looking at these two words but they are not the same in meaning.
Need for something is more to do with necessity and that it requires for survival without this one could not even imagine anything else. While want is a very broader term and it can be defined as when you are looking out for something which you can avoid if it’s not available.
In the case of Food, the Need is that we can feed ourselves for our survival but just to have too much of it when it’s not needed we cannot dump it without any need. This is how we can define need & want. Always ask for things when needed & not when you want them to have them.