I don’t think it’s going to be so long to be better. In really bad conditions, improvement is likely to be large within days in my opinion. I already experienced it. Sometimes I’ve been keeping my diet good (not great) for several weeks and I felt much, much better within days then. But there was always some reason to start eating crap – birthdays, holidays etc. I think you’re going to feel BETTER after 2 days on diet and MUCH BETTER after 1 week. Much better in our case means not so bad 🙂 But then, after several weeks, whoah – it must be really great!