I started the Ideal Protein diet a few months ago but I have already gotten my dress. (Didn't know about the diet when I ordered the dress). I've already lost 32 pounds and dropped almost 2 sizes. I'm not overly concerned because the bridal shop said that they could take my dress in up to 3 sizes. I don't have to wear the dress until October for my bridals (I bought early because it was being discontinued).
I was thinking of going in now to get an early fitting just to be sure that I don't lose too much weight. The last thing I want is for them to not be able to take it in enough. I don't mind having to go in for several fittings because I knew that would be the case when I started the diet. Am I crazy for wanting to go in this early?
Re: Alterations
Given the fact that you are actively trying to lose weight, it's best if you keep your dress with you and try it on about every other week.
Everyone loses weight in different places, so start measuring yourself (with a tape measure!) so you can start to track if you tend to lose more inches in the hip/waist/bust or consistent throughout.
I speak from experience. I lost a total of 13 inches from the time of purchasing my dress to the wedding day. Taking my measurements was a lifesaver in knowing that my dress would fit.
Just remember that if you lose so much weight that the dress can no longer be taken in, you most likely spend a great deal of money on having the dress completely taken apart and restructured and put back together. That is a lot more work then just taking it in.
I think it is great that you are losing the weight that you want but just don't go too overboard. I know from experience that when you start losing weight it feels so good that all you want to do is lose even more and you don't take the time to take a good look in the mirror and start loving the way you look...you are just too focused on the number on the scale.