I weight in about 230 right now, about 30 over ideal low weight (can not get below about 195) but I was interested in what 1.5 pounds feels like. My impression... not a while lot different. The wheels we a little easier to spin up for sprinting but honestly 1.5 pounds is not a huge big deal.
You are talking about about half of one percent weight difference. Of course you can't feel it!
Big guys really don't need to be weight weenies on the bike. They do, however need to stop eating an entire farm every day.