WORDS WHICH ARE BOTH COUNT AND NON-COUNT NOUNS

Some nouns can be both count nouns and non-count nouns with different meanings. This causes a lot of confusion. For example, the plural form of food is assumed to be foods, which is not the case as the word can be both a count and a non count noun. The following link will give you a clearer picture.

https://www.englishclub.com/ref/Nouns_that_are_Count_and_Noncount/