Rules concerning food are completely arbitrary:
Eat what works for you. When it stops working, do your research.
Keep your eyes on your own plate--nobody likes a food nanny.
Avoid spoiled food.
Remember that most "food rules" are made by manufacturers, advertisers, and those with an axe to grind (and they change every generation), and that your "eating healthy" may be seen as just the opposite by those with a different point of view. When someone says "I eat lots of fruit and whole grains; I avoid salt and fat" I think "I hope you have a robust liver, you're going to need it." But maybe you're a model fruitarian, who knows. I think often of the people of Roseto, who ate whatever they wanted washed down with wine, and avoided stress-induced disease as they did so. So don't stress over food, or anything else.