If it was made by man then it's probably not good for you (exceptions: butter, coconut/olive oil). If you can't pronounce the name of an ingredient it's probably bad for you as well.
I recently decided that it's the best and surest way to explain my eating habits to other people. Using words like 'lipid hypothesis', 'good and bad cholesterol', 'insulin response' or even something as simple as 'paleo diet' just makes peoples' eyes glaze over.