I have PCOS (a hormone problem that causes weight gain) and currently as a size 10 have a 30FF chest.
I'm very curvy and am prone to putting on weight due to a medical reason and the heaviest I have ever been has been a bit overweight at a size 12, with a BMI of maybe 26 or so. This has been when I've been really upset and bingeing, eating a hideous diet and doing no exercise.
How are people size 16 and beyond?