GPT and Insulin resistance: [9] In cases where AST/ALT ratio has been used instead of ALT, it has been found that this ratio is also correlated with metabolic syndrome and insulin resistance [10,11] AST/ALT ratio could be useful for distinguishing the etiology and severity of different liver damage as a value >2 may indicate advanced alcohol liver disease and on the other hand, AST/ALT <1 may imply fat liver accumulation and NAFLD.