One out of every three Americans is obese.

These individuals are at greater risk for additional diseases, since  obesity leads to other health problems, such as diabetes.

Obesity related complications are associated with an abnormal fat metabolism in the muscle. 

As a result, accumulated fat by-products inside the muscle affect insulin resistance.

To avoid the build up of fat by-products, fat must either be oxidized (burn fat, as in exercise) or stored (as benign fat) in muscle.

A team of researchers has examined the effect of exercise on fat accumulation in a new study involving five obese women.

In one session the women overate and did not exercise; in a follow-on session they overate and did exercise.
The researchers found that:

The findings indicate that even one bout of exercise helps to reduce the fat by-products inside the muscle, which affects the insulin sensitivity. The findings also suggest that a single session of exercise steers muscle fat towards oxidation, thereby avoiding the accumulation of fat by-products.