I am in the process of reading 'Protein Power.' On page 110 it says:

"You will also note that at the higher levels of carbohydrate per portion--where you will be in maintenance--a number of foods are listed as "unlimited." This means that reaching that carbohydrate level in a single serving would give you an amount too large for anyone to consume. In these cases, refer to the lower carbohydrate levels for that food to see how many grams a more realistically sized portion contains."