Meal Planning? Visualising food?

I’ve been coming up with a few ideas based around getting people to buy less food. One is simply meal planning – getting people to plan their meals and snacks in detail. The idea being that people would only buy the exact amount of food that they will eat – leaving no waste. This could be turned into some sort of product which could either be portable (enabling users to take it shopping with them) or a kitchen based device with the possibility to print out shopping lists.
I’ve also been thinking about some way of getting users to visualise the amount of food they are buying and how much they actually use. Maybe even something as simple as a product that takes up space in the cupboards/fridge possibly with reminders about the amount of energy that has gone into food that isn’t being used.
Just a few ideas that I’ve been thinking about before I commit to a single one and take it into phase 2.