It should still fit decently. You might need to get a waist or chest reduction done, but that is an extreme case.
In my case, when I was 220lb, I wore a 52 long and the waist had to be massively tailored so it would fit properly. After I came off the sauce and stopped training, I shrunk down to 180lb. I now wear a 42 long. So 50lb loss = about 10 inch loss on the chest measurement. My bodyfat is pretty much the same.
