There are green choices to be made EVERY DAY with regards to food.
It is not as black and white as you may think, take your average greasy spoon, cafe, dolling out all day breakfasts for £3, well even here there are choices you can make, swap you bacon for an extra egg, swap your sausage for extra mushrooms, and you will have lowered the environmental impact of that meal considerably.
So at the other extreme, it might be hard to find those organic free range mung beans that you have been searching for, but as long as you understand WHY you are looking for them them, you should be able to make a good second choice.
If your don't have time to shop at a number of independent green food retailers then go for Sainsbury's or Waitrose yes they are more expensive, but this represents the true cost of food.
Environmental Consultants Bristol
Environmental Consultants Exeter
Environmental Consultants London