The paleo idea is to turn from a carb burning body to a fat burning body. If you limit your carbs to between 100 and 150 a day, your body is forced to access fat stores to convert into energy. The reason you get so hungry in between meals is your body used up all its carbs and is not yet a fat burning machine, so you get mega hungry, especially if you are working out. Try it! You will probably feel like crap the first few days while your body adjusts and then your hunger will decrease a lot!