A couple of clients have talked with me about growing up having to eat everything on their plate when they were children and how this has stayed with them as adults.
They feel incredibly guilty leaving food on their plate when they're full and feel even more uncomfortable about throwing food in the bin because it is "wasteful".
I understand how strong our childhood connections with food can be and how as adults, we don't always consciously question our habits or look at how they developed, but the good news is you are not a child any more.
You are a grown adult, fully in charge of how, when, what & how much you choose to eat.
If it feels too hard to examine your relationship to food on your own, there are plenty of people who can help; ask your GP for a referral to a dietitian or counselor.
One way of avoiding the feeling of wasting food is to cook less for your meal or save the leftovers for the next days lunch. If you find you're not finishing your meals more than once or twice a week, it a sure sign you're still cooking too much.