Firstly, if you are sure that your weight is increasing only because you have increased your food intake, you should modify it. Reduce oily food, have 5-6 small meals in a day, have atleast 3 litres of water everyday to ensure regular bowel movement.
It is true that once you stop going to the gym, you tend to gain more weight than before. So i would suggest a brisk walk for an hour every alternate day, and after a week, every day.
If along with your weight gain, you have symptoms of easy tiredness
, less stamina and cold
sweat, then go in for a thyroid
profile to see if everything is fine.
All the best!