The rules of the Paleolithic Diet are simple: Only eat what was available to the early hunter-gatherers. Foods which are edible raw. All other foods should be avoided. In effect this is the factory specified diet.
Do Eat: Meats and Fish, Fruits, Vegetables, Nuts, and Berries.
Do Not Eat: Grains, Beans, Potatoes, Dairy, Sugar.
On this diet you don't count calories or carbs. You eat when you're hungry and stop when you're full. I snack all the time on nuts and fruit. Any food of any kind from the "Do Eat" list is OK. All foods from the "Do Not Eat" category are strictly forbidden--no exceptions! It takes some will power at first, but after a week or two the cravings for the old foods go away.