It depends on your recruitment agency / company in Qatar. If they require you to undergo GAMCA medical exam and submit it prior to mobilization, then you will have to face some hurdles at the hands of GAMCA clerical staff. Else if you recruitment agency will get you protector passport stamp by themselves, then you don't need GAMCA medical certificate anywhere. Once in Qatar, you will be required to undergo medical exam that only includes blood screening for HIV / Hepatitis and X-ray for TB.

Loose 5-10% body weight to reduce fatty liver problem, you can also take supplements such as Co-Enzyme Q10 & Vit E that will naturally reduce the fatty part of liver and the symptoms both. Good luck!