I suggest that if people genuinely have no idea how to be slimmer, they read "Why we eat too much" by Andrew Jenkinson which brilliantly summarises all up to date mainstream research on why obesity happens and how to tackle it.
And please don't fall for this mind trap that is offered to you, "poor thing, it is not your fault, you are a victim of circumstances, not your responsibility to change and no one is allowed to point out that it is". I wasted decades of my life in that trap - and there are clearly people on this thread still in that trap, who are desperately trying to shut me down because they don't like hearing obesity is something you can change if you want to. Too comfortable in the trap, and too desperate to have company in their with them to validate their victim status
For almost everyone who is obese, it is entirely your choice whether you still want to be obese this time next year, or not. If you are morbidly obese. It takes longer, but can still be done, or at least improved on.
Choose a healthy weight. It is a better life
And yes, I do also know what it is like to be obese for medical reasons, as I spent a year on strong steroids and the weight piled on. This is one of the few cases where it was genuinely not my fault, but that time has passed for me now, and I am getting the weight off.
For those who want a quick summary of the main points from Jenkinsons book, it is nothing radical. He points out that weight is more than calories in and calories out, as your body adapts to the calories available, and just uses fewer if you take in fewer, so your weight stays the same on less calories.
But cutting back on calories certainly helps! The main thing is cut out sugar and artificial sweetners ( which don't have calories, but do provoke the same insulin spike that sugar does- and insulin is the problem)
It is also crucial to eat plenty of green and leafy veg - again nothing radical!
Cut out margarine and vegetable oil, and highly processed food. Also avoid "grazing" and "snacking" as every tiny snack spikes your insulin again, whereas keeping eating to meal times lessons the number of insulin spikes in a day
So basically, cut out sugar and eat plenty of greens, which has been known for at least a century, although the science behind it not so much.
It is true that the dangers of margarine, processed food and vegetable oil have only been proved recently, as in the last decades, but they have been proved now, so there is no excuse.