This is one of those geezer posts the whippersnappers laugh at in the Over 50 forum, but for what it's worth:
Everybody knows lighter is better, in riders as well as bikes, but I've had a recent experience that really shows how important it is.
I'm 6'4" and weigh about 220 when I'm in pretty decent shape for a geezer. This summer, for several reasons, I didn't ride as much as I usually do and didn't take off the winter weight, and I gained about 30 pounds without really paying much attention (that's not as much on me as it would be on somebody who weights, say, 140, but it's still a lot).
Last month I was diagnosed with gallstones, and while I'm dealing with the insurance and scheduling surgery, I've had to watch my diet pretty carefully to avoid flare-ups. I feel fine other than the abdominal pain, which I can usually prevent, so I've been exercising pretty regularly, eating the way I always should and I've lost about 20 pounds. It's happened quickly enough that I've been aware of the change, and the difference is amazing. I felt pretty good before, but EVERYTHING is easier now, from getting out of bed to climbing stairs to riding. I notice it even walking to the coffee machine. My knee and leg pain have just about vanished, too.
None of this is news, but the difference is so great I thought I'd pass it along: Getting rid of a relatively few pounds (less than 10 percent of my body weight, in my case) is really worthwhile, especially if you've let some pounds creep up.