Empowered Health Course · Lesson 5 · 5:39
We've talked about the appetite center before — or maybe this is the first time, depending on where this module sits. I want to walk through the brain so you can see where these appetite centers are and how our genetics encodes them.
First, we have a homeostatic system located in the hypothalamus, where a set of neurons sense our energy intake. One group is called POMC and the other is called AgRP. If POMC gets enough hormonal communication, it senses that the body has enough energy and signals the rest of the brain that things are fine — you can attend to other things and don't need to seek out food. But if AgRP signals more strongly than POMC, it tells the brain it's time to find calories. That sets our motivation, learning, and attention in motion, and we start to seek food.
This works through the mesolimbic system, an emotional center that has to do with wanting — desire. We want caloric intake. We might prepare food, or, if nothing is ready, grab the easiest thing at hand — for me, probably goldfish crackers, or Oreos if they're around. The brain learns from this. In people with obesity, certain ultra-processed foods — high in sugar and fat — light up far more of these brain centers than they do in people prone to leanness. That leads to increased wanting and motivation for certain foods, which explains a lot about increased intake in those prone to gaining weight.
The third part is the executive system, more in the frontal lobe — sometimes called the "lazy executive." This is where the tools of behavior change come in: shifting habits in nutrition, movement, and sleep, and integrating them into the context of our lives. Inserting healthy habits and refraining from others is the holy grail — and one of the more challenging parts of living.
We also have other tools. Medications act on the mesolimbic and homeostatic systems, decreasing the wanting and reward pathway and giving our executive function more freedom. They can ease the path to best weight by lowering some of these barriers and making life feel more natural. When we've successfully treated the disease of obesity — which lives in the deep brain — life is easier; hunger isn't as loud.
I've often heard, "For the first time in my life, I felt full," or "For the first time, I left food on my plate." Then people understand why someone else might leave several bites of cake — not because they have more willpower, but because they got a powerful signal from the body that enough is enough. They're responding to a different biology, both in the body and in the brain's circuitry. So sometimes the right medication makes life a bit easier.
This transcript has been lightly edited from the video for readability. For the complete experience, please watch the video above.