I do believe that if you loose weight your breast size will go down as well. It really all depends on the amount of weight you need to loose and should loose as well. If you loose 20 pounds you could do down a cup size. It really depends on what size you want to be. Hope this helps.
yes your breast size will go dowm if you lose weigh because breast have a fat component, but you also consider that they will be more falls too.