Take a sheet of paper and write at the top: "Things I could do instead of eating". Then list all the things you could do instead. For example you could:
Read a book
Watch videos on You Tube
Call a friend
Go for a walk
Just to name a few. Be sure to make is realistic things you would actually do. Now post that on the fridge or the 'forbidden cupboard". Next time you go for that snack, look at the list and pick something on it to do. Complete that task and see if the craving passes. The beauty of a craving is that it does have an end, and if we can hold power over it by deciding to do something else, we become stronger. Sure you might give in after whatever activity you picked to do, but everytime you choose to do something else you are learning to resist that craving and eventually you will be able to say NO.
It certainly can't hurt to give it a try.