Don't believe the hype: Despite what a recent article in Time reported, working out does lead to weight loss, and we've got the evidence to prove it.
At age 23, Brandy Blackburn of Charlottesville, Va., couldn't walk up a flight of stairs without getting winded. She couldn't fit into roller-coaster seats or go hiking or canoeing with friends. At 335 pounds, the new mother knew something had to change.
She started to diet and work out — just "hanging in" for 20 minutes on the treadmill at first. But eventually, through a combination of hard work at the gym and a healthy diet, Brandy lost 173 pounds. Now, two years later, she maintains her healthy weight with a combination of fitness classes, weight training and cardio.
"I've found that if you can lose weight by cutting calories, you can do it so much faster combining it with exercise," she says.
While Brandy's results are extraordinary, her experience with exercise and weight loss is not. That's why she and many others — including diet and fitness experts — knew that something wasn't right when a recent Time magazine story claimed that regular exercise makes it harder to lose weight.
Wait — what?
The article hinged on a 2009 study published by Timothy Church, M.D., and colleagues at Louisiana State University's Pennington Biomedical Research Center. In the study, overweight women were put into four groups — three were assigned varying amounts of exercise, and a control group that maintained its normal activity. None of the women were asked to change their diet.
The results were complicated: After six months, all groups had lost some weight — even those who didn't exercise. Still, those who did exercise lost more weight than those who didn't. The two groups that worked out 72 minutes a week and 136 minutes a week lost exactly the predicted amount. But here's where it gets tricky. Those who exercised the most — 194 minutes a week — somehow lost less than expected. The reason: They ate more to reward themselves.
Church thought the findings were intriguing, but warned that they "should not be interpreted as suggesting that lower doses of exercise are more effective in producing weight loss than higher doses." Unfortunately, that's exactly what some people did.
"The point we tried to make is that exercise does not give you carte blanche to eat whatever you want," Church says.
He points to another of the study's key findings: Women in the exercise groups lost about an inch around their waistlines, effectively lowering their risk for cardiovascular disease and diabetes.
What the research really says
Exercise is crucial to keeping weight off, and there's plenty of data to back that up. In 2009 researchers at the Harvard School of Public Health crunched some 40 years' worth of diet and exercise numbers and concluded that in studies lasting more than two years, a combo of diet and exercise leads to significantly greater weight loss than dieting alone. The National Weight Control Registry, which tracks more than 6,000 people who have maintained weight loss for a year or more, reported that 90% of them exercise for an hour per day, on average.
But what about the claim that exercise weakens your self-control — that jogging a lap around the track compromises your ability to say no to an extra slice of pizza afterward?
According to Mark Muraven, an associate professor of psychology at the University of Albany, every person has a set amount of self-control "resources" — sort of like credits. The more self-control you use now, the less you'll have later.
"However, for many people, exercising doesn't take much self-control, so it doesn't deplete resources," he says. "Even more significantly, I have found that self-control can be strengthened through practice. Even if you don't like to exercise but you make yourself do it, you can improve your overall self-control ability."
Add to that one more dubious exercise myth: that working out makes you lazier after you leave the gym because your body is trying to preserve precious calories. Church proves it false. "We actually had step counters on everyone during the exercise study, to see if people who started exercising got more sedentary the rest of the time," he says. "We know their activity level outside of exercise didn't change."
So, if exercise will help make you thin, won't sap your self-control or make you hopelessly lazy, and will also help lower your risk for all manner of diseases, what could possibly be keeping you out of the gym? Not, we hope, some magazine story.
