The rule is everything has to either come from your yard, or has traveled for less than an a couple of hours. Nothing from the grocery store.
A strong emphasis will be placed on foraged food, hence the name. Farmers markets are probably the best way to meet the criteria.
(okay, olive oil, soy sauce, wine are exceptions to the rule)
Thinking outside the food box can be a challenge so to get some ideas there are a few forage related links posted.