How do you get over all the wasted food?

When I was growing up,, my parents didn't want to waste ANYTHING. If fruit was starting to turn we baked with it. We froze things if they were close to going bad. My mom always saved leftovers, and we had at least one dinner a week that was a fridge clean out of all the random things. We were encouraged to eat EVERYTHING on our plates at mealtime. It made me really reluctant to waste food and I'm having a hard time with my LO not eating everything at mealtime. I try to adjust the amount that I give him but it's constantly changing.