Physically true or not I also consciously ‘shrank’ my stomach. I aimed to go to bed slightly peckish, and over time reaching this point took less and less food.
There’s definitely something in that. I think it is part physical, but also part mental.
The human body is designed to store energy (in the form of fat) for those occasions when food is in short supply - which for all of human history (until the last 50 years or so) it has been for the overwhelming majority of the human race. Or put another way, most of us are genetically programmed to eat more than we need to when the opportunity arises. For the last 50 years that opportunity has been relatively ubiquitous rather than occasional.
The challenge for those wanting to lose weight is therefore ‘reprogramming’ yourself to need less food.