كل بايت ولا تاكل مقيل which actually means: eat yesterday's leftovers but not something you ate some of and kept some since early in the day for a later meal.
Recycling of food is to actually use those leftovers to prepare a totally different meal. Let me give you examples.
How many times have you grilled chicken and nobody ate it or let us say a large portion was left behind?
Ever thought of recycling that chunk of meat into something much more edible?
How about preparing, shawerma sandwiches with it? or a pasta mix, even something easier chicken soup with mushrooms or any other type of soup? Here we go? This is called recycling?
I remember my sister and myself once transformed grilled fish into mini fish koftas with parsley and lemon. It was yummy.
A fruit salad can end up as a smoothie.
So basically everything can be recycled in life, not only materials but also and especially food!