Increasing knowledge of human biochemistry provides new insights into how obesity (or even simple excess weight) damages health and reduces life span. Wired notes that "experts have realized for decades that large people die young, and the explanation long seemed obvious. Carrying around all those extra pounds must put a deadly strain on the heart and other organs. Obvious but wrong, it turns out." The harm caused by fat is in fact due to imbalances in chemical signals that damage organs over years and decades. Even a modest amount of excess fat greatly increases the risk of suffering all the most common age-related conditions.