This project is an open-source collaboration for individuals to find tasty, sustainable diets that will likely exist in off-world colonies. Try it out - you'll find it to be quite healthy (and yummy).
Open pull requests for recommendations and corrections whenever you have input - we're all learning this together.
Check out the list of off-Earth soil-grown plants.
Start a new directory or page with your diet rules and recommendations, but be sure to explain your reasoning and include source material.
There is only one general rule: Be Reasonable
Although there will be limitations on what plants and animals can grow in alien environments, there will also be marketplaces and trade routes carrying imported (earth-based) foods for sale. However, keep in mind that these foods are likely more rare and expensive, so be realistic and try to limit those extra foods in your diet. For example, it is highly unlikely red meat (raised animals) will be available in Ex-Terran Colonies, and therefore it should be extremely rare in a Martian diet.
NOTE: The organization of the diets and recipes will likely shuffle during the early stages of this repo, so please browse around - you might find some hidden kernels of delectableness.