The soft-drink industry vowed to voluntarily curb selling sugary sodas and other high-calorie beverages in schools, a move that was taken under threat of litigation by critics who see the industry as a prime culprit in a national obesity crisis. The promise offered no guarantee that schools would go along with the restrictions, though many districts have taken such steps in recent years. Under the agreement reached by beverage distributors, the American Heart Association, and former President Bill Clinton's foundation, no full-sugar beverages would be sold in schools. Other beverages would be sold in serving sizes of no more than 120 calories. And in high schools, carbonated diet sodas would be available only along with alternatives, such as bottled water, sports drinks, and juices with no added sweeteners.