Humans eat for more reasons than just nutrition. We eat because we are bored, lonely, scared, aroused, etc. Once you’ve got the derangement caused by insulin out of the picture … you may still have to deal with pathological eating. I could probably eat a lot of cream too. But the thing is I rarely eat past my off switch because having an off switch for me is such a novel thing I’m enjoying the experience.
Overeating because they eat the wrong food is certainly one explanation.
That is another. And both are facets of the problem.
Another way of looking at this is from the point of view of the energy status of the cell.
If people over produce insulin, that inhibits fats getting into their mitochondria to be converted into energy. Access to glucose is usually inhibited by insulin resistance as cells try to protect themselves from hyperinsulinaemia. This explains the paradox of a man swimming in energy (glucose and NEFA) and hungry and lethargic.
And that increasing insulin explains why leptin has to become deranged. It also explains why Adipose cells have to become deranged. Also why the pancreas has to become deranged. And why these are all force multipliers upon the derangement.
Example take adipose derangement. The pancreas makes more insulin when there is fat AND glucose present in circulation. It likely does that to signal adipose tissue to draw down energy and store it - adipose is supposed to remove fat from circulation when there is glucose available. As fat turns of the fat spigot, the pancreas calms down and makes less insulin.
Fat cells can become increasingly more insulin resistant as they become stuffed with energy … and as they become resistant to insulin they release more fat into circulation even when insulin is high, so now the pancreas has to make more insulin and the fat cells are like deaf people being yelled at. That is then a perfect recipe for a runaway control system.
Diabetic obesity is a series of runaway trains. All started by an overproduction of insulin, and each runaway train further piling on more demand for insulin. What causes the original insult is much debated, but one of the early possible causes is the environment in the womb.
This is insulin. It is a massive molecule containing over 150 amino acids
This is a glucose molecule
Glucose gets through the placental barrier, insulin doesn’t for obvious reasons. If the mother has a lot of glucose in circulation that she herself is able to make plenty of insulin to deal with, then she won’t be considered diabetic. However the fetal pancreas has to run at a higher rate to control the loads of glucose coming in. That is like a starter kit for insulin resistance for the child. That is pretty early on in the process.