Several years ago, Carlos Herrera Macias, 55, learned that he had type 2 diabetes. He already knew about that obesity-related disease—his mother had had it too. But his doctors soon delivered a second diagnosis that was unfamiliar to Macias. "They told me that something was wrong with my liver," he recalls.
Macias has fatty liver disease, a condition in which deposits of fat accumulate in the liver and eventually impair the organ's capacity to filter blood. In his case, the problem had progressed to a condition known as nonalcoholic steatohepatitis (NASH), which is characterized by liver inflammation and formation of scar tissue in the organ. People who are obese or who have diabetes are more likely to develop NASH than other people are.