It may not be fat. Have you been to a doctor or sports therapist to determine this?
Alot of people mistake 'water retention' for fat.
Water retention is when the body stores extra water in the body walls.
A diet high in sodium increase water retention. So if you are training hard as you possibly can already and it ain't shifting, then reduce your sodium intake.
Just look on packets of food products and see how sodium it has, eat less sodium (salts) and with your workout, it should decrease.

Peace!