Do you remember having earnest childhood exhortations to 'eat up everything on your plate because there are plenty starving in Africa'? It seems that Gordon Brown does and took it to heart. We now have the political equivalent, a war on waste. Only with the current obesity panic it is don't buy it in the first place rather than eat it.
Food waste is an important problem. All those 'buy one get fifteen free' offers and use by dates that suggest that your Worcester Sauce will turn into nuclear waste at a particular time in a couple of years don't help either. However, to suggest that this is anything other than peripheral in a crisis that affects the supply and price of basic staple grain crops is to duck the important issues. The world food system is a bit more complicated than that.
How about the dysfunctions of a fully commercialised and heavily monopolistic capitalist food system? How about the monopoly over supply and retail exercised in the developed world by the big supermarkets? How about the continuing dispossession of highly productive small farmers? How about the displacement of local markets by global ones? How about cash cropping as a substitute for food production, of which biofuels is only the latest emanation? How about the erosion of sustainable rural communities? I could go on adding to the list and you can explore more here.
Malnutrition kills millions annually. Millions of poor people that is. Cutting down on that extra banana, which you bin when it goes manky, will only reduce the income of farmers rather than save the world.