A very common phrase: "We bought lots of groceries (food)." "We bought a huge cake, some candy, and fruit."
Normally, English speakers do not say "we buy lots of food."
Present perfect : We are "buying lots of food (at the moment)
Past tense : We bought lots of food
Future tense : We will buy lots of food
Never say Candies. It is Candy (plural and singular).
Never say foods. It is Food (plural and singular).
Hope this helps.