You can outrun a bad diet, but the average person won't. The average American diet is 3600 cals/day (https://www.businessinsider.com/daily-calories-americans-eat..., https://archive.is/IURse). The average person needs ~=2250 cals/day to maintain a healthy weight (https://www.webmd.com/diet/calories-chart, women need 1600-2400 averaging at 2000, men need 2000-3000 averaging at 2500). Jogging a sustained 5mph burns about 600 calories/hour (https://runrepeat.com/calories-burned-running#calories-burne...). Now it's just algebra, the average person takes in 1400 calories more than they need in a day, so while you could try to outrun that diet it keeps up a pace of 5mph for about 2.5 hours EVERY DAY. So the most accurate advice is "a person can out-train a bad diet but the vast majority of people won't" but the advice that's most likely to lead the most people to the goal they're actually pursuing is "you can't out-train a bad diet".