I don't get it: How can you not see that eating food you don't need to eat is wasting food? If you throw away food, it has been made for nothing and goes to waste. If it hadn't been made, that would have saved resources, and nobody would be worse off.

If you eat food you don't need to eat, same thing: If it hadn't been made, that would have saved resources, and nobody would be worse off. Exactly the same end result: Food was made for no net beneficial end result; resources were wasted.

What's your definition of "waste", that they can be anything but the same thing?