1) When food is served at home, sometimes some of my family members can't finish the food that is served to them. So sometimes I finish the left over food to avoid israaf, but if I want to follow an islamic diet and avoid overeating then am I allowed to bury the food or give it to animals in my area?

2) Also if there are no animals around then burying it is not haraam right?

1) Yes, you can feed that food to animals. It is better than burying it.

2) Yes. It is OK

However, let us learn the culture of serving/ taking small quantity of food, and if we need, take more.