For decades, conventional wisdom (and Jane Fonda) said cardio was the best exercise for weight loss. Then strength training muscled its way into the spotlight as the must-do move for revving your metabolism and losing weight in your sleep, prompting many exercise enthusiasts to join #TeamNoCardio. So a few years ago, Duke University researchers took to the lab and conducted the largest study of its kind to compare the two and get an answer once and for all.
After 8 months of tracking 119 overweight and previously sedentary volunteers while they performed resistance training, aerobic exercise, or a combination of the two, the clear winner was aerobic exercise. By a lot. The cardio group lost about 4 pounds while their resistance training peers gained two. Yes, the weight gain was attributed to added lean mass.
However, that muscle mass didn’t lead to any meaningful fat loss over the course of the study. In fact, the aerobics-only group shed more than 3.5 pounds of fat while the lifters didn’t lose a single pound despite the fact that they actually exercised 47 more minutes each week than the cardio group. Not surprisingly, the cardio-plus-resistance group improved their body composition best—losing the most fat while adding some lean mass. But they also spent twice as much time in the gym.