yeah anytime you are supporting your weight while not sitting is using up calories at an accelerated weight. every pound you gain you multiply that factor, so instead of a factor of 205 and then you weight 206 that one pound is tallied with every gallop per foot or stride so say a.......
run at 205 = 20,000,000 strides= 140,000,000
a run at 206 pounds= 20,000,000 strides= 212,000,000
thats nearly a DOUBLE stress load even though youve only gained one pound!