The main point of eating paleo is to eat only natural, whole foods that have not been processed or genetically modified in any way. Paleo also cuts out foods that can cause allergies and other similar issues, even though they are a whole food. For more information on this, check out Beginners Guide to the Paleo Diet. The paleo diet is based off of what humans living in the paleolithic era would have been able to eat. They were hunter/gatherer cavemen, and literally lived off of the land. They could only eat natural foods. So basically, if you could grow or hunt it, you can eat it.
So, what can you eat?
Meat & Poultry: all meat is fair game, as far as I have seen. Grass-fed meat is the best choice if you have the option.
Beef, pork, chicken, turkey, venison, bison, duck, etc.
Seafood: all fish and seafood are excellent as well. We try to buy wild caught rather than farm raised fish, but that is not always an option. Catching it ourselves is our favorite, though not always practical.
Shrimp, lobster, scallops, crab, salmon, tilapia, bass, flounder, swai, grouper, catfish, clams, oysters, etc.
Breakfast Meats: Sausage and bacon. Look for brands that do not contain any nitrates, nitrites, sugars, MSG, or chemicals. The ingredients list should only include meat, spices, and water, and you should know what everything is. If there are ingredients you haven’t heard of, it is likely not paleo. This is very hard to do, and I end up cheating here. I do not buy anything with nitrates/ites or chemicals in it, but I do buy bacon and sausage with sugar in it – as long as it is plain sugar and not corn syrup or another chemically altered sugar. Ideally I would be making all of our sausage from scratch with ground pork, but I haven’t gotten that far yet.
Vegetables: These are very important, and best if included in every meal.
Lettuce, romaine, spinach, cabbage, kale, bok choy, watercress, greens, peppers, tomatoes, onions, mushrooms, broccoli, green beans, zucchini, carrots, avocados, eggplant, squash, brussel sprouts, asparagus, sweet potato, sugar snap peas, snow peas, water chestnuts, turnips, beets, celery, etc.
Fruit: All fruit is paleo, but it is high in sugar, so limit how much you eat if you are trying to lose weight. Berries are lowest in sugar content.
Nuts: Nuts are very versatile and can be used to make many things. They are high in calories, so eat them in moderation.
Almonds, almond milk, almond butter, pistachios, coconut (unsweetened), coconut milk, cashews, etc.
Oils: Natural oils are great, healthy sources of fat.
Coconut oil, olive oil, bacon grease, avocado oil, sesame oil, etc.
Natural Sweeteners: Eat in moderation.
Pure maple syrup, honey (local & unpasteurized is best), agave nectar, molasses
Other: Flavorings. I use these in every meal! Instead of table salt, switch to sea salt and use it sparingly. Too much salt can lead to health problems.
spices, herbs, roots, garlic, lemon, lime, vinegar, pure extracts (such as vanilla), cocoa, etc. Fresh herbs and roots are in the produce section (ginger, horseradish, parsley, basil, etc.), while dried roots and herbs are in the baking aisle with the other spices. Be careful to check ingredient lists of anything packaged. Make sure seasoning mixes do not include anything besides spices, and extracts are pure. You don’t want any additives like sugar, corn syrup, or mono-sodium glutamate.
What Can’t You Eat?
Grains: No grains are allowed on the paleo diet.
Dairy: No dairy, though some people eat whole, all natural dairy like butter that has not been processed or pasteurized.
Legumes: Because these can cause food allergies, they are excluded. Peas or beans that come in a pod like snow peas and green beans are more pod than legume, so some (like me) say that they are okay. For more information on legumes, check out what Ultimate Paleo Guide has to say here.
peanuts, peas, beans, lentils, soybeans, etc. Anything made from these, then, is also not paleo.
Unnatural oils: All refined oils. Soybean oil, canola oil, vegetable oil, corn oil, etc.
Unnatural sweeteners: sugar, cane sugar, palm sugar, brown sugar, corn syrup, etc.
Avoid processed foods. If you need to buy something that comes in a package, always read the ingredients list before buying.
Give yourself time to adjust into eating paleo. It will take a while to figure out which stores carry the different items you will be eating regularly. A natural food store or a grocery that offers a bulk option may be the best place to go to buy nuts.
Nutritionator offers a great food list here.