Happiness makes your belly grow bigger?

I am thinking about the corelation between happiness and the accumulation of fat on your belly. That does not necessarily mean being obese or does it?

From my own personal experience, when I am happy and feel free, I put on more weight and my belly grows bigger. But when I am stressed, regardless of how much I eat, I tend to remain slim.

Does that mean different internal parts of our body can in fact "feel" happy? Is it something to do with the "thinking cells"? Perhaps what we are is not entirely based on what our heads think; it also depends on what we and our body feels.