To answer your questions:
1) Alcohol can result in an elevation in ALT. However, the AST is typically elevated more often. As to the amount, that would vary from patient to patient.
2) Obesity and weight gain is associated with NASH (non-alcoholic steatohepatitis) which can then lead to an elevation of the enzymes. A liver ultrasound is advised for further evaluation.
3) Although possible, I am not aware of a direct connection between elevated liver enzymes and cholesterol. It is well-known that many of the cholesterol-lowering medications can elevate the liver enzymes.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.
Thanks,
Kevin, M.D.