OP I am bigger than you. I used to be in the same hopeless position but lately I have "cracked" it.
The answer is, count calories. Yeah, that oldfashioned, outdated, outmoded and thoroughly debunked thing!
If you are morbidly obese you can have about 1800 a day, that is what I have, and you log them online at MFP.
1800 is achievable if you choose the right foods.
If you like to eat 3 x a day, make that 500 calories per meal and that leaves 300 for cheats, drinks and snacks. No food is off the menu. Just log it.
500 buys you a BIG salad, with some protein on top like chicken breast, ham, boiled eggs, tuna etc. You just have to be really careful about the dressing. Lemon juice is OK, or balsamic, though to be honest a tablespoon of salad cream is only about 15 calories.
With 500 you can even have a ready-meal like spagbol. Just a regular one, not a diet one necessarily. I found the best thing to do is to cook a ready meal such as lasagne, spagbol etc and serve half of it on a bed of broccoli or sprouts, and that does two meals, each one about 400 calories.
If you want to go crazy and have, say, fish and chips that is 1500 calories so you can have just a cup a soup for your other two meals = 1800.
I think we have overcomplicated dieting. I have lost 55lb counting calories. I never feel hungry or deprived. In fact, it's fun working out new things you can spend that 1800 calories on!