You are not alone with the pregnancy weight gain that does not come off. I kept mine until my son was 17!
One thing about "lessening your intake" is that you need to boost your nutrition at the same time. If your food is not very nutritious, eating half of it is not really a sustainable change.
I think your best bet in the PI is the wet markets. You should be able to find some inexpensive and healthy alternatives there. I don't really look at my food as a "diet." I am going for long term ideas that I can keep doing forever.
You have a great motivation regarding your Grandson. Keep the goal of visiting him at the top of your mind and you can do this. Try looking at this older post and see how long it will take you to get to where you want to be. Then put the blinders on and go for it. I will be glad to help you in any possible way if you comment on any of my posts, reach me in Discord, or fb or anywhere. I know you can do this if I did :)