I used to be overweight myself, and I know that it is very hard to lose weight, and not simple at all, so by all means I do not mean to be demeaning in this post, I only wish to help.
I had a surgery performed (unrelated to my weight) , and I could not eat any form of solid or even semi solid food, just liquids.
During this time I basically only drank soup.
But i did not limit myself, I drank until I was full, let it be a bowl, two, three or more it matter not.
I also strutted some vitamin supplements down my throat.
I did no extra exercise, in fact I moved even less seeing i needed to rest from surgery.
Slowly I transitioned to semi solids and eventually solid foods once more.
But my appetite was severely diminished and eventually,losing about 30kg, I was overweight no more.
Now, there are some studies that link blended foods as being more 'filling' than their exact solid counterpart, such as:
This might explain the effect it had on me.
But i fear that relapsing is very easy using such a method, and I'm not even sure soupmaxxing is effective, I only speak of personal experience.
Another option would be surgery, such as gastric bypass, gastric band, etc...
Which is risk full, and I'm certain you have already thought about that.
As a side note, i must say the one thing that struck me as most different when losing weight was simply how much less out of breath I am, I can actually run (for a small bit) without feeling as if my lungs have collapsed into black holes now.
I can only give you my best of wishes, godspeed!
TLDR: soup