Conventional wisdom says that dieting is essential to weight loss and that exercise alone is generally insufficient for weight loss.
However, a new study looked at a related topic – preventing weight gain. This study compared three groups of obesity-prone rats. The control group was sedentary. The second group of rats exercised regularly in running wheels. The third group of rats was sedentary and on a calorie-restricted diet. All three groups ate the same kibbles though daily servings for the calorie-restricted group were 20% less than that for the group of runners.
Unsurprisingly, the control group turned out to be obese at the end of the study. The other two groups staved off obesity. However, the runners were metabolically healthier in terms of insulin sensitivity, cholesterol, burning more fat and they also seemed to have more metabolic activity within their brown fat. Interestingly, gut microbes in the runners were different from gut microbes in the calorie-restricted group, so exercise had a probiotic effect even though all groups had been fed the same kibbles.
This study suggests that exercise alone can deliver results that are far superior to dieting alone – at least for rats trying to avoid obesity. It seems reasonable to assume that this would be true for humans too, though it is obviously important to focus on both exercise and calorie intake while eating healthy food.