For me, no, not mechanically. I lost 39 lbs. in 2009-2010 with P90X and calorie counting over a period of about 9 months. When I finally got around to playing golf again, my swing was the same ol' horrendous POS it was when I was heavier. That said, I had a major increase in balance, stamina, and overall confidence about my appearance. Not only that, but I was getting less nicks and pains after rounds and was more fresh the next morning.
My swing itself didn't start to improve until I began to implement the proper technique. Still, despite this, the last thing I want to do right now is go back to my old body
There certainly was an adjustment period for me when I returned to the game after the long layoff, but it didn't take too long to get used to the body differences.
I encourage all seasonal golfers to take advantage of the endless winters we have to deal with by getting in the gym and kitchen and making the effort to improve their bodies. It's a good way to pass the time while waiting for spring to arrive.