Choose Thin Friends
Just looked at a C172N ground school manual.
With an empty weight of 1460# -- Check the sheet.
and full standard tanks and NO baggage
you and your passengers can weigh 600# with clothing.
With long range tanks, everybody has to go on a diet and get rid of 60#
I fell into that trap many years ago and flew once or twice with four seats filled and long range tanks and was maybe 100# overweight on takeoff.
V speed correction factor is 2% and of course climb and runway performance decreases.