I grew up in a family of four. Each one of us was obese, though my father, at times, approached being merely "overweight". Much of his weight issues were a beer belly, a memento of being an alcoholic. Though we didn't know it, each one of us had an eating disorder. Most of the time, the only "disorders" people see when it comes to food are those in which people don't eat enough or throw up what they eat.
A lot of people think that the only psychological problems related to a bad relationship with food are connected to trauma or abuse. I did not start to overeat due to trauma, but rather because it was normalized for me. I was thin as a kid up until 4th grade when my family's habitual overeating caught up with me and I got fat. Had that behavior not been "normal" within my family, I believe all that followed would have been different.
Once I became overweight, it became a much broader issue as I became defined by my body and other issues complicated the matter. After my weight marginalized me and I became heavily objectified as a result of my body size, food became part of a more sophisticated and byzantine psychological pattern. Once fatness defined my life and food became the only ally I could trust as well as a hated enemy, the routine overeating turned into full-blown disordered compulsive eating and bingeing. What started as mere patterning as a result of being the child of parents who overate routinely (due to their own issues, most certainly) turned into emotional reliance.
The patterning was started by my mother, who, as I have said before, fed us poorly (mounds of white bread, potatoes, whole milk, cheap fatty meat, salty canned vegetables and fruit in syrup) and too much and complained when we didn't eat what she prepared. For example, she would bitterly complain if she sat and peeled many potatoes and the bowl remained largely full by the end of the meal. It never occurred to her to simply prepare less. As a child, I had no awareness of what was happening nor the consequences of eating as my family did. Since I'm 47, there wasn't nearly as much propaganda or talk about food and body size in education at that time. Even if there had been, I'm not sure that it is the responsibility of a 10-year-old to figure out how to eat properly. At that time, there was just the food pyramid, in its primitive form.
By the time I had an inkling of what was going on, I was trapped in an intricate web of psychological dependence on food from which I could not extricate myself, particularly not without a good support system or the awareness and insight that comes from education and maturity. By the time it was made clear to me that I had a problem (i.e., being fat and therefore eating too much), I was too indoctrinated by routine, family culture, and biological inclination built by habitual overeating and too young and lacking in the psychological tools to climb out. This was how my disordered relationship with food grew.
A lot of people talk about how once you become an adult, you suddenly are "responsible" for what goes in your mouth and can no longer "blame" your parents. To me, this is like repeatedly breaking a child's legs until their bones are distorted and weak and telling them when they reach 18 that they are now supposed to be capable of running because they should be capable of finding whatever it takes to simply be different or "better". Forget the past damage and just overcome it all now that the calendar has turned to some magic number. It's just not that simple.
It has taken me many decades of my life to get to where I am now and I continue to pick at and untangle knots in the web I was trapped in. I still feel stuck to it in spots and occasionally feel sucked back in and trapped, but most of me is free most of the time. The one thing that I implore anyone who is trying to lose weight to do is to stop oversimplifying and talking in Yoda-isms ("there is no try, do"). There's a reason most people regain weight after they lose it and I absolutely believe it is this oversimplification and denial of the complex psychological issues that go into changing ones relationship with food. You can't do it forever with the mental tools of brute force, abuse, pat and trite mantras, a stick-to-it attitude, etc. Eventually, for most people, the psychology that got them fat in the first place will re-assert itself and they will regain.
Make it as complicated as it is and take the time to understand that it's just not so simple for most people. You didn't get messed up in a day, week, or even a year. You got messed up over a lifetime. It isn't a short-term problem and it can't be fixed with a short-term solution (and I count dieting culture as a part of "short-term").