The upper limit of normal for ALT activity has been recommended to be lowered to <30 U/L in men and <19 U/L in women. These changes have been suggested to be diagnostically useful in subjects with nonalcoholic fatty liver disease (NAFLD). Our aim was to investigate the prevalence and spectrum of NAFLD with regard to the new ALT guidelines in 233 women with class II/III obesity. We compared our prior reference range for ALT (ULN < 30 U/L in women) with the new standard. Our study demonstrates that only 86 patients O besity is a major health issue in the United States that is associated with increased morbidity and mortality. 1 The prevalence of obesity (body mass index [BMI] Ն 30 kg/m 2 ) in the United States is 31%, and the prevalence of morbid obesity (BMI Ն 40 kg/m 2 ) is even growing at a greater rate than obesity. 2 The degree of obesity is further subdivided into class I (BMI Ն 30-34.9 kg/m 2 ), class II (BMI 35-39.9 kg/m 2 ), and class III (BMI Ն40 kg/m 2 ). 3 Individuals with class II obesity that is associated with medical comorbidities or class III obesity alone are considered suitable candidates for gastric bypass surgery. 4