Research has shown that leptin is an important hormone with a hand in many metabolic processes. It undoubtedly has widespread effects that may influence diabetes as well as obesity. Recent work from Harvard researchers has tied leptin to a crucial pathway in fat metabolism in muscle. This pathway suggests a role for leptin in clearing fat out of cells and sheds light on the connection between diabetes and obesity. In the Jan. 17, 2002, issue of the journal Nature, a team led by Barbara Kahn, Harvard Medical School professor of medicine and chief of the Division of Endocrinology, Diabetes and Metabolism at Beth Israel Deaconess Medical Center, and Yasuhiko Minokoshi, visiting associate professor of medicine, established the new connection in the body’s metabolic machinery. In light of new knowledge about leptin’s role in fuel metabolism, it makes sense to consider the idea of targeting leptin’s actions to treat obesity. Obese people develop resistance to leptin, so the ability to target a downstream pathway and bypass leptin resistance may be more beneficial than treatment with leptin itself. The direct path of leptin action also establishes an important link to insulin resistance and diabetes.