I've tried just about every diet on the planet, and the one I have found most effective is a fish and vegetable heavy Low carb diet. My body is really sensitive to carbs, I look at them and weight goes on.
Lots of veggies,
Lots of lean meats,
Lots of good fats (olive oil, avocado, nuts)
Lots of Eggs.
Lots of Cheese.
Because this diet does not limit fat, the food is extremely satisfying and once your body gets used to it and your insulin rates go down, it does a good job of suppressing your appetite so you don't need to worry about counting calories. To some extent you can eat whatever you want, just whatever you do don't cheat (no cheat days, no sneaking snacks etc).
Pretty much this is what is off limits
No Bread, crackers, pasta. buns, pizza Just about anything that has wheat
No corn, potatoes (fries, chips, baked, or mashed) , rice
No sweets (cookies cakes etc)
No breaded meats (chicken strips etc)
This is the stuff you need to watch our for (eat in moderation)
Sugary fruits (bananas, apples mangos, melon etc) Most berries are OK though
Sugary or starchy vegetables (sweet peas, beans, carrots, sweet onions, beets)
Milk (because of lactose)
This diet has worked for me, but it can be expensive (carbs are cheap, protein isn't), and you have to follow it religiously, because it can be pretty calorie dense, and it works on limiting how much of your food energy actually gets absorbed by your body (eating carbs makes my body absorb all calories much more efficiently, hence weight gain).
Best of luck,
J.