Aerobic training is the best mode of exercise for burning fat, according to a study by US-based healthcare group Duke Medical.

Researchers studied 234 overweight or obese adults with participants being randomly assigned to one of three exercise training groups: resistance training (three days per week of weight lifting, three sets per day, 8-12 repetitions per set); aerobic training (approximately 12 miles per week); or aerobic plus resistance training (three days a week, three set per day, 8-12 repetitions per set for resistance training, plus approximately 12 miles per week of aerobic exercise).

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 actually gained weight due to an increase in lean body mass.

Aerobic exercise was also a more efficient method of exercise for losing body fat. The aerobic exercise group spent an average of 133 minutes a week training and lost weight, while the resistance training group spent approximately 180 minutes exercising a week without shedding pounds.

The combination exercise group, while requiring double the time commitment, provided a mixed result. The regimen helped participants lose weight and fat mass, but did not significantly reduce body mass nor fat mass over aerobic training alone. This group did notice the largest decrease in waist circumference, which may be attributed to the amount of time participants spent exercising.

Resting metabolic rate, which determines how many calories are burned while at rest, was not directly measured.

The report, which is published in the latest edition of the Journal of Applied Physiology, is the largest randomized trial to analyze changes in body composition from the three modes of exercise in overweight or obese adults without diabetes.

Leslie Willis, an exercise physiologist at Duke Medicine and the study's lead author, said: "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."