Yeh it's such a shame that so much food is wasted. Especially meat and dairy, essentially meaning that those animals went through all that suffering for absolutely nothing. However to counter your point, if people stopped buying food then the means of food production would grind to a halt. What incentive would farmers have to produce food? or for shops and supermarkets to buy it in. I think a more realistic approach is for everyone to start producing at least some of their own food. I've only got a small garden but still managed to grow quite a lot last year.