Yes, see my post above. Basically the idea is that everyone has an internal feedback system which sends a signal telling you whether or not to eat more food. Just like eyesight, for the most part this system worked reasonably well in the ancestral environment. However the system isn't perfect, particularly when exposed to a modern diet. (By analogy, a lot of people have trouble reading without glasses.) John Walker refers to this system as a "food clock."

If your internal food clock does not work correctly, and you don't exercise conscious control over what you eat, then your weight will tend to drift upwards over time.

I find this hypothesis to be very plausible and consistent with the available evidence.

As far as the gut bacteria hypothesis goes, I am skeptical because if it were correct then obesity could be easily combatted with so-called "nutrtionism," i.e. by adding or subtracting a few key components from the diet but otherwise eating ad libitum. As of yet, nobody has found a nutritionistic solution to obesity.