They wound up with participants who either were or were not obese and, separately, were sedentary or active, completing aerobic exercise, weight training, or both types of exercise on a regular basis.
Then they compared exercise habits and obesity and noted an interesting pattern. The incidence of obesity, especially extreme obesity, was much lower among active people than the sedentary, whether their activity was aerobic or resistance-oriented.
But those men and women who reported completing both types of exercise — who jogged and lifted or walked and downward dogged, for instance — were about 50 percent less likely to be obese than inactive people and about 20 percent less likely than people who participated in aerobic exercise or weight training alone.
In other words, it appears that “doing either aerobic or muscle-strengthening exercise is good for a healthy weight, but doing both is better,” says Jason Bennie, a senior research fellow in physical activity epidemiology at the University of Southern Queensland, who led the new study.
This study relied on participants’ remembrances of exercise, though, which can be unreliable, and asked about them at only one point in people’s lives. So, it cannot show whether exercising now necessarily thwarts obesity in the future. It also cannot establish whether, in some cases, being obese prevented people from being active, meaning that their weight determined their workout routines and not the other way around.
Perhaps most important, it does not tell us how augmenting walks or other aerobic activities with weight training might help us to avoid obesity. Dr. Bennie and his colleagues speculate that aerobic and resistance exercise produce differing effects on our metabolisms, hormones, appetites and even the structures of our brains that, synergistically, remodel our bodies and minds in ways that reduce the likelihood we will gain weight.
More study is needed, of course. But in the meantime, those of us hoping to keep our weight under control might want to consider cycling or walking to the gym, where we might want to pick up some weights.