One of main the principles of a healthy diet is to eat a wide variety of foods each day. The will help ensure you eat a wider range of nutrients each day to meet your requirements and prevent the likelihood of too much one particular food.
Rather than worry too much about what you shouldn’t eat, try to base your diet on as wide a range as possible of vegetables and fruits. Try to eat as many different colours of vegetables and fruits each day as the beneficial nutrients found these foods generally vary by colour. The cancer project have produced a Nutrition Rainbow which shows a range of vegetables and fruits according to colour and the beneficial chemical compounds they contain. The Nutrition Rainbow is available online at: http://www.cancerproject.org/resources/pdfs/2009RainbowPoster.pdf