The problem with dieting is that the body already set the weight it WANTS to be, and it don't care if it is healthy or not, it is what ever it currently is. But it is willing to negotiate for LARGER.
What it is not willing to negotiate on is being SMALLER. I have done the lower calorie thing where I lose about2 lbs in week 1, 1-1/2 lbs in week 2, 1 lb in week 3, nothing in weak 4, spelling error on porpoise, and then started gaining weight without once going above diet caloric target intake.
The body adjusts, it goes into saving mode, it becomes more efficient, and it defeats your diet with ease. You can lower your intake more, and gradually continue losing 1 /2 to 1 lbs per week for a while, and that works if you are looking to shed 10 lbs or so. But by the time you have lost 15 lbs, your food intake required to lose weight now leaves you without the nutrients required to keep the body healthy. Continuing the diet is going to damage your health more than maintaining this new weight, but the body still has some room to be more efficient so you cannot maintain your new weight, and since you have weakened yourself, chances are you will get sick shortly.
Now the fun part. It is hard to cut back on food. It is harder still when you are not getting any benefit from the discomfort. Eventually, the vast majority of US are incapable of keeping up the caloric intake required to maintain the lost weight until the body admits that it likes this new weight. The body is angry with you, you deprived it, and now it wants assurances it is not going to be starved again, so instead of just gaining 5 lbs back, or the original 15, it wants 20 to 30 lbs, 5 to 15 lbs more, just as insurance against you attacking it again.
My first diet and exercise for losing weight was at 180 lbs. Then a year later when i was 200 lbs. Then again a few years later at 210 lbs. 220, and my last diet was at 230 lbs about 10 years ago.
Want to know what my weight is and has been for 10 years straight? 240 lbs. Yes, it varies, on a really bad week I have hit 250 and on a good week I might hit 231, but basically, my body has set itself to 240+/-5 lbs.
Oh, and I had liposuction at about 200 lbs, by the time the swelling went down I was looking fine at, 205 lbs. Now all the fat is inside where my organs are, I do not recommend that as a solution. Fat will always find a way.
Unless you are a fortunate person with extreme willpower and likely some exceptionally helpful live in family who can make sure you remember not to eat and do not constantly tempt you with food, dieting is not likely a good answer. Just suck it up and live with it.