I hope you see this. I have been in the medical profession for about 12 yrs. I want to give you my take on what the doctor said. I am somewhat in the same class. I am 6'0", 53 y/o, and 247#. Doctors do not take into account body type or muscle mass. I plan on losing down to around 190, but
... my real emphasis is going to be bodyfat percentage. I'm a big guy and I'm not about to sacrifice muscle mass; however; I would not have a problem being under 12% bodyfat. Don't worry about the weight, worry about how much fat you are carrying. Bodyfat around the mid-section is a cardiac killer. I've seen some guys who were quite active and in pretty good shape just drop dead.
Anyway, don't worry about your weight, but do get it off your middle. A slight calorie restriction combined with aerobic exercise three to four times a week will do the trick. Be sure to add weight training and adequate protein intake to that to preserve your muscle mass.