I'm a bit of a yo-yo dieter myself, and the only thing i have ever had success with is a Keto diet. Basically not allowed to eat any sugar or carbs - ever. But you must eat 50% protein and 50% fat.
Essentially, this makes Bacon the healthiest possible food you can eat. So bacon and eggs for breakfast is ideal, as a pork scratchings as a healthy snack. Want a bowl full of double cream for desert? Go for it!
Eating the above diets (plus a few vegies,, lots of steaks and cheese etc) i can easily lose a couple of stone in a month. It's the future.
I'm on it now actually. I started 10 days ago, and as of this morning i'm 10lb's down.
The only reason i fall off it is due to work commitments and holidays really.