A "Zone" type of diet works (in theory) by balancing the fats, carbs and proteins IN EACH MEAL so that you don't get huge insulin spikes, so that the food is slower to digest, and that there is a constant supply of protein to the body. Therefore you really shouldn't eat a lot of carbs in ANY meal. And not all carbs are considered the same for this diet. EVERY meal should be 40:30:30 with plenty of fibrous veggies as your main carbs. If not, then you're not really doing a 40:30:30 diet in the original sense of the diet. I hope you also realize that you still need to limit total calories on this (or any) diet if you expect it to work long term?