Obesity results in decreased fatty acid oxidation rates in muscle tissue. Weight loss alone does not correct impaired muscle fatty acid oxidation. But exercise training begins to increase muscle fatty acid oxidation in as little as 10 days.
Those beginning an exercise program can expect better weight loss results over the long term than those relying on diet alone. Increasing muscle fat oxidation is extremely important for sustained weight loss. But exercise is critical for overall health, and should not be viewed as simply a weight loss tool.