> As those went away I gained weight, even though my diet has not changed much.

I'm not sure if this is your point, but if your "calories in" stayed the same, and "calories out" significantly decreased, it's expected that you would continually gain bodyfat until you reach a new equilibrium point. That seems to have been what's happened.

If the amount of exercise changes, your diet should optimally change with it - but perfectly managing your habits in this way is hard.