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The Brain and Obesity. Part 1 – The Primal Brain

The Brain and Obesity. Part 1 – The Primal Brain

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The amazing brain.

The brain. So beautiful and complex. Often the root of our problems but also our solutions. Sometimes our greatest ally and other times a pain in the ass. And have you ever thought about who tells you that your brain is so amazing? It is your brain itself! So in all its magnificence, perhaps it’s a bit of a narcissist, or just confident? I will let you decide that one. 

What does the brain have to do with our weight?

The reality is our brain might have just about everything to do with our weight. Now, this is likely going to be a multi-part blog – maybe two parts. Or, three parts? My brain will ultimately decide. I want to share with you how I think about our brain’s involvement in managing our weight. I find this simplistic breakdown makes it easy to understand and can really offer an opportunity to know what the hell we are dealing with when we want to eat that cookie or piece of cake. There are similar explanations out there with more or less details, but I am, of course, biased since my brilliant brain came up with this analogy, and so it is, of course, the best analogy!   

I generally think of our brains as having two parts:

  1. The Primal Brain – you may have heard this called the limbic brain, the lizard brain, the ancient brain, etc. 
  2. The Modern Brain – our pre-frontal cortex. The part of our brain that allows for higher thought processes and cognitive functions.

These two parts remind me of my brother and I growing up. We were constantly fighting, and me being the older bigger brother, I constantly bullied and picked on my little brother….to help build character? Now my little brother is bigger than me. Instead of physically fighting, I prefer a much more diplomatic approach. Our entire childhood wasn’t me beating my brother up. We also had some great bonding moments, albeit few and far between. Our primal brain and modern brain have a similar relationship – most of the time, they are fighting, but other times they can work together to achieve incredible results! 

So let’s start with the primal brain!


As you probably guessed, our primal brain is an older part of our brain. In fact, it is the part of the brain we share with the animals! Essentially, the sole function of the primal brain is to keep you alive. NO MATTER WHAT. It recognizes and avoids danger, but it also keeps everything in homeostasis (a big science word for balanced).

So if you are cold, you are off-balance. Your primal brain tells you to go and put on a coat (or if you are feeling feisty and want to make fathers everywhere angry, it tells you to turn up the thermostat). Similarly, if you are hungry, the primal brain says go and find food! The colder and more hungry you become, the more powerful the signals from the primal brain will become. You know those times where you have eaten very little throughout the day, and you figuratively and, in my case, literally could eat a horse? Ya, your primal brain isn’t happy with you.

You might have also noticed you don’t often have an intense craving for a salad. Instead, it tends to be the fries, rice, chips, chocolate bar, or other highly palatable amazingness that you seek. Your primal brain ain’t no fool. It knows that a plate of fries is not only going to give it the calories it so desperately wants, but it will also taste effing AMAZING too! One thing to keep in mind is that the primal brain ALWAYS wins. You might think you have incredible willpower and tenacity, but if the primal brain wants something bad enough, it will make it happen. Biology ALWAYS wins.

Why do we crave calories?

Now hold on a second! If our primal brain is so focused on keeping us alive, why wouldn’t it crave healthy broccoli?!

Well, there are two reasons for this: 

  1. Your primal brain is a hedonist. It wants all the pleasure and none of the pain. When was the last time broccoli gave you a mouth orgasm? Fries, on the other hand… I mean, have you ever had fresh McDonald’s fries after an evening bender? I rest my case.
  2. Your primal brain is focused on the present. It couldn’t give two flying f*$ks if eating the plate of fries will cause a heart attack ten years from now. It is worried about keeping you alive RIGHT NOW. As far as it is concerned, you are starving and the zombie apocalypse must be happening, so we need to eat and consume as much as possible of whatever we can get our hands on.

Can you teach an old brain new tricks?

You can think of our primal brain like an old man set in his ways. Our primal brain was really developed for a world that existed some 30,000 years ago – where danger was lurking around every corner and food, shelter, clothing, and all the nice sh*t we take for granted today was much harder to come by. Now clearly, this old man has done some great work keeping us alive and supporting us in creating our advanced society. Still, he is unfortunately now yelling at the kids to get off his lawn and refusing to change/adapt to our ever-advancing society. 

I know. He sounds like a crusty pain in the ass, and we have only covered what I consider the biological part of the primal brain today. Just wait till we get to the dramatic and emotional part of the primal brain in part 2! And FYI, my brain has now decided this will be a 4 part blog series. You are welcome. 

Until next, my friends. Remember: biology ALWAYS wins!

Dr. Dan

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