As a guide the lunch should provide you with one third of the daily nutrients required to keep you healthy.

The simplest illustration is the “eatwell plate”, showing what your daily intake should be made up of. You may already be familiar with it.
We have listed some of the really useful websites we have found on nutrition:
Healthy lunchbox - part of the Food and Drink Federation
Food Standards Agency – a month of lunchboxes
5 a Day – the official 5 a day website