Well, my mate Michael Pollan (who isn't really my mate but rather the author of Food Rules) gives us a new Mantra to stick by:
"Don't eat anything your great-grandmother wouldn't recognise as food."
By this he means, that you should imagine yourself and your Great-grandmother, strolling the aisles of the supermarket together. What do you think she would be able to pick off the shelf and pop straight into the trolley, without explanation? A Go-GURT Portable Yoghurt tube? I don't think so.
There are literally thousands of products on our shelves that our ancestors would not even realise were food.
Why shouldn't we eat this stuff? Besides the chemical additives? The corn and soy derivatives they contain? Or the plastics in which they are packaged (some of which are probably toxic)?
Well, these foods are designed to make us want to eat more of them. You want to eat more, so you have to buy more. They push our evolutionary buttons - our innate preferences for sugar, fat and fat (ever seen a child have to try chocolate more than once before they accept it? How about brussel sprouts then? See, we a programmed to like the 'bad' stuff!)
These tastes are difficult to find in nature, but cheap and easy to process into our foods. We are getting way too many of them than is good for us.
Apply the "Great-Grandma Rule"* and most of this processed badness will stay out of your trolley.
According to Pollan, the sub-rules of the Great-Grandma Rule are:
1. Avoid food products containing ingredients that no ordinary human would keep in the pantry
2. Avoid food products that contain high-fructose corn syrup
3. Avoid foods that have some form of sugar (or sweetener) listed among the top three ingredients
4. Avoid food products that contain more than five ingredients
5. Avoid food products containing ingredients that a third-grader cannot pronounce
The list goes on, but that is probably enough for now.
Go out and try this rule and let me know how it goes.
* NB: If your G-G was a terrible eater or cook, use someone else's for this task. Preferrably a Sicilian or French grandma.