Exercise more effective than strength training for weight loss
By Anna Sayburn
Aerobic exercise is better than weight training for losing weight and reducing body fat, a study has confirmed. Combining the two does not increase weight loss or reduce body fat more than aerobic exercise alone.
Aerobic exercise, combined with a low-calorie diet, has been the mainstay of treatment for obesity and overweight for decades.
Aerobic exercise means you're working hard enough to raise your heart rate and break a sweat. Fast walking is an example of aerobic exercise. Others include swimming, cycling, and jogging.
However, resistance training - using weights to strengthen your muscles - has become more popular, and is often incorporated in weight loss programmes. But we don’t know for sure that it is more helpful if you want to lose weight than doing aerobic exercise on its own.
This study involved 119 people who were overweight or obese, who did little or no exercise at the start of the programme. They were randomly divided into three groups, to take part in weekly programmes of aerobic or resistance exercise, or a combination of the two.
People in the aerobic group did the equivalent of 12 miles of exercise a week. People in the resistance group lifted weights three times a week, while people in the combined group exercised for 12 miles and lifted weights three times a week.
The programme ran for eight months. Researchers then compared people’s weight to their height, and measured their lean body mass, body fat, and diet, at the start and the end of the programme.
Both aerobic exercise and the combination of aerobic and resistance exercise reduced people’s weight by between 1 and 2 kg, and reduced their body fat.
Resistance exercise decreased percentage body fat, but not by as much as aerobic or combined exercise. People who did resistance exercise had, on average, a slight gain in weight (less than 1 kg). This was mostly due to an increase in lean body mass.
Combining aerobic exercise with resistance exercise worked well. People who did the two types of exercise lost weight, reduced their body fat, and increased their lean body mass. However, they didn’t lose more weight than people who did aerobic exercise alone, despite spending about twice as long each week on their exercise programme.
This was a randomised controlled trial, which is one of the best ways to compare how well treatments work. The results should be fairly reliable. It would be useful to see longer studies, as people often put weight on again after a weight loss programme has ended.
To lose weight in a healthy way, people need to eat a balanced diet with fewer calories, and to increase the amount they exercise. Aerobic exercise seems to work better than resistance exercise for weight loss. Resistance exercise is helpful in terms of increasing lean body mass, but aerobic exercise seems to be the most important overall.
L Willis, C Slentz, L Bateman, et al. Effects of aerobic and/or resistance training on body mass and fat mass in overweight or obese adults. Journal of Applied Physiology. 2012; 113: 1831-1837.