Get your thyroid problem corrected first it will help you a lot to reduce weight...Weight gain happens either due to addition of extra calories or due to failure to spend calories consumed...these extra calories deposited in our body as fat..for weight reduction you have to consume less calories and spend more...avoid junk foods,carbohydrates like rice etc,avoid oily foods...add proteins and fibre rich foods to your diet with green tea,green leafy vegetables, fruits...do regular exercise at least 2 hours a day...be in a regular fallow up with your physician they will do the needful.