Obesity, inactivity could outpace smoking in cancer death risk Obesity, inactivity could outpace smoking in cancer death risk Obesity and inactivity could someday account for more cancer deaths There's no guarantee that obesity and inactivity will surpass smoking Calculating cancer's link to obesity is difficult in part because of an counterbalanced by this steady rise in obesity trends beginning in the '70s," says Wender. The obesity rate has tripled since the early 1970s