Again, personally the best I've ever done is 3 days low carb and then a carb up - but I also was doing carb/fat rotation where I'd drop the calories from carb (rice or sweet potatoe) and replace the calories w/ some flax oil - so same total cal, but diff P/F/C ratios. Any more than 3 days and I would get turn into Linda Blair w/ my head spinning. Why don't you schedule carb ups every 4th day? What is the point of letting yourself go that long? And what is the purpose of lots of shitty sugar on your carb up days? I'm not sure what diet you are following , but I'd keep my carbs to good starches like yams, brown rice & oatmeal along w/ veggies on hi carb days and just veggies on low carb days - or just oatmeal & veggies on low carb days.
The point of dieting is to find something that is more of a lifestyle than a 30 day misery session. Your diet shouldnt' make your life miserable.