I lost 50 lbs in the last 6 months. I was diagnosed with diabetes and went on a low carb, high fat diet. I'm 6'4" and went from 235 to 185 and I noticed a huge difference with climbing and overall speed plus endurance is better. I'm still not very fast, but now I can't imagine riding 50 lbs heavier. Now if I can just get a lighter bike...but that's another thread.