While dieting to shed those extra pounds can be challenging, keeping the weight off can be a much tougher feat. But a new study in the September issue of Medicine & Science in Sports & Exercise by UAB Kinesiology Distinguished Professor Gary Hunter, Ph.D., says resistance training may be the key to maintaining weight loss long term.
About half of all American adults are classified as being overweight with a body mass index between 25 and 29 while more than one-third are obese with a BMI of 30 or above, according to the Centers for Disease Control and Prevention.
“Obesity is associated with heart disease, several different cancers and an increased risk of diabetes, just to name a few,” says Hunter. “The cost to the United States due to obesity and the comorbidity associated with obesity is in the billions of dollars. It’s a large problem across the world, but we are, unfortunately, leading the way in obesity rates.”
Hunter’s study, funded by a $2.5 million grant from the National Institutes of Health, compares the effects of aerobic exercise and resistance training on activity-related energy expenditure (AEE) and activity related time equivalent (ARTE) index after weight loss. The study is part of a larger investigation into the connections between dieting, exercise and weight loss.
For this study, Hunter and his team placed 140 premenopausal women on an 800-calorie diet. The team also assigned the women to one of three groups. One group exercised on a treadmill for 40 minutes three days a week. The second group did resistance training using weights for 40-minute sessions three days each week. The third group of dieters did no exercise. All three groups lost an average of 25 pounds. The dieting ended when they all reached a BMI of 25.
Before and after the diet, the researchers measured each woman for non-exercise activity thermogenesis (NEAT). The term NEAT describes the energy that individuals expend when they are doing something other than eating, sleeping or exercising.
“NEAT is the energy one might expend while fidgeting or walking up stairs or walking to your car or grocery shopping,” Hunter says.
NEAT typically decreases after weight loss, making it harder for people to burn calories and maintain their weight loss after a diet. Researchers say it is because the human body reacts to diets as if it were starving and therefore tries to survive by conserving energy by burning fewer calories.
Using computed tomography, the UAB researchers measured the visceral fat, the fat inside the peritoneal cavity, of each woman in the study. Visceral fat around the abdomen and internal organs like the stomach is associated with diseases such as type-2 diabetes, cardiovascular disease and even breast cancer.
In a previous paper, Hunter showed that exercise slowed weight regain and prevented the regain of visceral fat for one year. But in the present paper, Hunter found an added benefit of resistance training.
“We found that resistance training is very good at increasing NEAT,” says Hunter, “and it’s particularly good at improving the ease for doing things like climbing stairs or walking the dog. And so, because it’s easier, then you tend to do more of it, and this study showed that was the case, whereas the non-exercise group actually decreased their NEAT after the weight loss.
“If you’re planning on losing a lot of weight, resistance training is going to be particularly good for improving ease of movement and doing chores and whatever you need to do,” Hunter says. “Because of that, it will increase NEAT, which will be very beneficial in maintaining weight after going off of your diet.”