Exercise Cuts Risk Even Without Weight Loss
Landsberg notes that it is quite possible for obese people to be fit. That's because fitness is more than weight loss. It means losing the visceral fat around internal organs, improving insulin sensitivity, cutting blood pressure, and much more.
On the other hand, being obese isn't healthy.
But Stefan says some obese people are in particular need of an intensive lifestyle-change program. His team is now exploring the effects of such a program.
"At the moment, we see that the lifestyle intervention in general has effects on reducing liver fat more than total body fat," he says. "Many people stop the program because they are not happy with a body-weight decrease of just a few kilograms. But the liver fat goes down very much, and their metabolism increases very much. They must realize this has benefits. So it is important to tell people to stick with it, even if they don't lose much weight."
Interestingly, not everyone gets the same benefit from the same amount of exercise.
"The most important factor is not how much you exercise, but what the effect your exercise has in increasing your fitness," Stefan says. "It looks like at the same level of exercise, some people increase their fitness and others don't. It looks like there are fitness non-responders. And those non-responders don't have that good an effect of exercise on liver fat."
These "exercise non-responders" may need more exercise. Or they may require diabetes drugs to get their risk factors under control. Stefan and colleagues are testing these interventions in ongoing studies.
"We are seeing fitness as the most important factor, and then on top of that reduction of intake of carbs has a strong effect," he says. "So far, our recommendations are increased physical activity, four hours per week of moderate activity, and reduced carbs. We also recommend a reduced intake of saturated fat."
Reports on the Stefan and Wildman/Wylie-Rosett studies -- as well as an editorial by Landsberg -- appear in the Aug. 11/25 issue of Archives of Internal Medicine.