A new study has claimed that sugar intake is not directly associated with nonalcoholic fatty liver disease, as it was earlier believed. Rather, high-calorie diets promote the progression of this serious form of liver disease. Researchers conducted a double-blind study of healthy, but centrally overweight men to compare the effects of high intakes of two types of sugar, glucose and fructose, in two conditions - weight-maintaining (moderate-calorie diet) and weight-gaining ( high-calorie diet). In the weight-maintaining period, men on neither diet developed any significant changes to the liver. However, in the weight-gaining period, both diets produced equivalent features of nonalcoholic fatty liver disease.