People who want to lose weight are better off running than lifting weights -- or even than doing both, researchers at Duke University say.
The researchers compared people who did aerobic exercise -- running, swimming and walking, for instance -- with those who did resistance training such as weightlifting and with people who did both kinds of exercise. Those who got up and moved burned the most fat, the researchers said in a recent Journal of Applied Physiology.
"Given that approximately two-thirds of adults in the United States are overweight due to excess body fat, we want to offer clear, evidence-based exercise recommendations that will truly help people lose weight and body fat," said Leslie Willis, an exercise physiologist at Duke Medicine and the study's lead author.
It is the largest randomized trial to look at how the three modes of exercise in overweight or obese adults without diabetes -- 119 people by the end of the study -- changed body composition.
The news might be disheartening to a whole trendy cohort of exercisers who have become enamored of resistance training, often in combination with aerobics. Resistance training does have benefits. Research has shown it improves glucose control, for one thing. And then there's the look of those six-pack abs.
Participants were randomly assigned to one of three groups: resistance training of three days a week, or about 180 minutes; aerobic training of about 12 miles a week, or about 133 minutes, or both.
The groups assigned to aerobic training and aerobic-plus-resistance training lost more weight than those who did just resistance training. The resistance training group gained weight due to an increase in lean body mass.
The combination group lost weight and fat mass, but did not significantly reduce body mass or fat mass compared with aerobic training alone. This group noticed the largest decrease in waist circumference.
"Balancing time commitments against health benefits, our study suggests that aerobic exercise is the best option for reducing fat mass and body mass," said Cris Slentz, a Duke exercise physiologist and study co-author. "It's not that resistance training isn't good for you; it's just not very good at burning fat."