In case you are, or know someone who, struggles with obesity, and have noticed that durable weight loss is a lot more difficult than most people realize, and are looking for vindication, look no farther than …
Here is an article which very briefly mentions how in obese people, fat cells stop doing their jobs, which means among other things that the person suffers from inflammation and insulin resistance. Which two factors, of course, would make it far more difficult to lose and/or stop gaining weight.
There might be a chicken and egg thing going on here. In other words, did the person become obese in part because their existing fat cells stopped regulating insulin properly, and stubbornly refused to hand over the energy they were storing? Creating a death spiral where, the fatter the person got, the hungrier and more fatigued they felt? In other words, is obesity partly a biochemical problem, and is it perhaps true that the more biochemical, the less of a character issue it is?
If you want to learn more about the biochemistry of obesity, check out the book Good Calories, Bad Calories by Gary Taubes.