Depends, if you're really talking about food.
I would say :
Food that are stale, are still food not to be wasted. (sound like my grandma...lol)
if you're talking about some useless that you own and seem wasteful to be thrown away.
I would say:
This is a big "white elephant" that I've kept for no reason.
圖片參考:
http://imgcld.yimg.com/8/n/HA00945776/o/701101020081113873435380.jpg