What is your food rule?

In the New York Times, Michael Pollan writes:

Will you send me a food rule you try to live by? Something perhaps passed down by your parents or grandparents? Or something you’ve come up with to tell your children – or yourself?

I will post your suggestions on my Web site and plan to include the best in a collection of food rules I’m now compiling. Thanks in advance for your contribution.

Here is my food rule:

Buy foods as if they were priced correctly.

Just for example, if energy were priced correctly, from a long-term environmental perspective, much local food would be comparatively less expensive and much highly processed and packaged nationally marketed food would be more expensive. If petroleum-based nitrogen fertilizer were more expensive, and if hog and poultry producers were responsible for external costs, then there would be fewer factory farms and more farms would raise multiple animal products and crops in a more holistic nutrient management system. If advertising did not favor silly and less-nutritious branded products, basic healthy commodity foods would be trendy.