It’s an age-old question among those who are out to fight fat: Which is more important for a healthy weight, diet or excerise?
It’s also the subject of a debate taking place at Toronto’s Mt. Sinai hospital this week between two leading obesity researchers, Dr. Yoni Freedhoff (team diet) and Dr. Robert Ross (team exercise).
“In medical school, we are taught diet and exercise go together,” said Dr. Sandy Van, a newly educated doctor of family medicine with a focus on obesity.
But exercise alone, without dietary changes, is “not an effective tool” for weight loss, Van said.
She worries people who start exercising will get discouraged and give up when the scale doesn’t budge.
“Exercise is excellent,” she said. “It is something we need our patients to do because there are so many benefits.”
But weight loss requires you to consume fewer calories than you burn.
“As important as exercise is for good health, the effort it would take to outrun your fork to lose weight is vastly underestimated,” said Arya Sharma, chair of obesity research at University of Alberta, in an email to Metro. “Just think about how many hours in the gym you would need to burn off 1,500 calories. Now consider how many seconds it would take you to eat or drink them back.”
According to Harvard Medical School, it would take an 185-pound person more than three hours of brisk walking to burn off a 1,400-calorie Big Mac meal.
Most medical organizations say the standard treatment for obesity is losing five to 10 per cent of body weight. And it’s true if you achieve that, you reduce many of the risks.
But losing weight is fiendishly difficult. Keeping it off is even harder. As Dr. Van said, “The body defends its highest weight.”
That’s where Dr. Robert Ross’s research comes in. He argues the dangers of obesity can be reduced even if the numbers on the scale never are; by prescribing an all-around healthy lifestyle that includes a balanced diet and, especially, exercise.
In many people with obesity, fat is packed around essential internal organs such as the heart, pancreas and liver. It’s called visceral fat, and having too much dramatically increases the risk of all sorts of problems, from abnormal blood sugar to heart disease to high cholesterol.
A 2009 review by Dr. Ross and his colleague Dr. Alison J. Bradshaw identified 11 randomized studies that showed exercise helps redistribute fat away from the danger zone around the abdominal organs, even if overall body weight doesn’t change very much.
Ross’s studies have also found exercise helps increase the body’s sensitivity to insulin.
That means, basically, that exercise helps an obese person’s metabolism be more like a healthy person’s, and makes them less likely to develop diabetes and all the health problems that come with it.
The best part? The metabolic benefits start to show after just one workout.