But if I eat more I'll get fat.

Fat is not a storage unit, it's a hormone producing organ. Fat cells can get larger. Most cells in our bodies have that capacity in fact. Your body has multiple mechanisms in place to maintain your optimal weight set point and if you provide it with more than it needs (which by the way is not the case in recovery because you are so severely energy depleted) then it can easily manage that without having to resort to increasing fat cell size.

When someone is energy balanced they are not keen to eat 6000-8000 calories a day and in laboratory settings where subjects are purposefully overfed even though they are at their optimal weight set point already and not energy deprived, it is difficult to get the force feeding to result in much weight gain and as soon as the study is over they return to their pre-study optimal weight.

Yes, you live in a society that is completely obsessed with the fear of fat and completely misunderstands how the body works as well.

There is no such thing as morbid obesity. There are individuals who are naturally and optimally above-average weight and they live normal and healthy lives. Our optimal weight is largely determined by our genetics.

There is a thing called inflammatory obesity and that is when the fat organ is no longer functioning correctly — like when any organ stops working then there are numerous chronic conditions that may occur. However food and exercise have nothing to do with the onset of that condition at all.

More likely culprits are a complex combination of: chronic stress, genetic predisposition, exposure to endocrine disruptors in our environments, low socioeconomic status (which is a phenomenal stressor), sleep deprivation and possibly decades-long cycles of going on and off diets.

For more detailed information regarding the misconeptions we have in our society about fat, please read:

Bingeing Is Not Bingeing

Fat: No More Fear, No More Contempt (the entire series is hopefully worth a scan, but particularly from Part V onwards).