I'm a bit late to the party and please note that this observation is based on a sample size of one, so take that with a spoonful of salt, however:
I've tried a few things to lose weight and I'm now below 90kg. I started at 116kg about 6 or 7 years ago. I first lost 23kg by changing my diet to less carbohydrates and more veggies and salad (where I previously ate none). I was out of a job at that time.
This diet was assisted by a doctor and I was forbidden from doing much sports.
After I got a job and relaxed on my diet regime, I gained another 10kg. I stayed at around 103 kg for quite a bit. Perhaps a year ago, I started chewing my food better and thus ate much less food. I lost weight to the point of weighing about 96kg.
Then came another tough time with the kids and I tried keeping spirits up with carbohydrates, so I remained at 96 for another while.
In last two or three months I went down to 88.8. Again by just eating less.
During the last three years, I had a brutal bout of ulcerative colitis and spent two weeks in the hospital with a blocked colon where I couldn't keep down any food for about ten days.
I weighed about 82 kg when I left the hospital but due to my lack of strength, just about all the weight lost was muscle mass, not fat. I was back on my normal weight a few weeks later.
Now my theory is this: Even though I never wanted to believe it, eating less calories than you actually burn during the day plain does work. There are two caveats though:
Without actually measuring your level of activity and your muscle mass it is a bit hard to define what your daily needs actually are.
And second, and much more important, if you suffer from depression and stress, you are much, much more likely to have to wage a HUGE internal battle with yourself to actually keep to your diet. And when you almost inevitably fail to adhere to your diet on an especially hard day, you're WAY more likely to think yourself a failure and eat too much the next day as well or even give up on the diet altogether.
And since you already failed, in your mind, you'll fall back on the carbohydrates to boost your mental stability again.
I believe, much like with every addiction, that this is primarily a mental issue. Which makes it all the harder to overcome. It's not easy being in a mentally stable state when your overweight contributes to your depression.