Real Food by Nina Planck is an amazing book. A look at what we really should be eating and how we should be eating it. Nina Planck believes eating real food is what our bodies are meant to eat and it's the chemicals, GMO's (genetically modified foods), pesticides among other things that messes up our health and in turn our planet.
In the book, there's a great "Most contaminated" with pesticide residue produce list (scored of 1 is least contaminated and 100 is the most contaminated). The list comes straight from the Environmental Working Group:
Bell Peppers 66
Grapes (imported) 64
Sweet Corn 1
Sweet Peas 13
This is a great list to keep with you when you're shopping because if you can't afford the high price of organic produce, you should be choosing your organic and conventional produce wisely.