Judging by popular beliefs about obesity, we might think weight and eating, like drug use, are also controlled by dopamine, but this is only partly true.
We have a built-in “weight thermostat.” Our bodies store energy in the form of fat. When our fat cells are full, they secrete the hormone “leptin” and we feel less hungry.
Also, when we lack nutrients, our brain secretes “orexin” to make us feel hungry. When we eat and have plenty of circulating nutrients, the brain secretes “CRH” to make us feel full.
However, eating results in higher levels of dopamine as well. So the news isn’t completely clear when it comes to dopamine and obesity.
Genetic components of weight also include sensitivity to all these signals. We may have more or fewer receptors for the signals, or more or less sensitive receptors.
So weight regulation is more complex than drug addiction. We don’t “need” drugs and alcohol, so leaving them out of our lives is a more straightforward cure. But we do need to eat, so it’s not surprising to discover that regulation of eating is complicated.