How Sugar Hijacks Your Brain (Neuroscience)

Posted by:Lindsay S. Nixon

Welcome to Day 2 of the Sugar Elimination Series :) 

Yesterday I shared with you that foods containing sugar trigger a special region in the brain (the nucleus accumbens) that is ground zero for all conventional addictions such as gambling and drug abuse. 

This response can even be viewed on brain scans, which is what you were looking at in yesterday’s blog post. Sugar lights up the nucleus accumbens like a Christmas tree. 

Today I’m going to geek out about brain science, explain how all this crazy hijacking happens, and show you that you’re not weak, you’re addicted (and food manufacturers are your enablers). 

“We are all exquisite reward detectors. It’s our evolutionary legacy.” - Anna Rose Childress, clinical neuroscientist at the University of Pennsylvania's Center for Studies of Addiction. 


Sugar sends a signal to the brain’s pleasure center (nucleus accumbens) which does two things: 

  1. Activates the reward pathways, causing a surge of dopamine (the feel-good hormone) and serotonin (which affects mood, feelings of well-being, and inhibitions) and
  2. Causes your prefrontal cortex to release hormones that persistently urge you remember this lovely experience so you’ll make it happen more often. 

Are you surprised to learn that once you eat sugar you’re no-longer completely in control when it comes to deciding whether or not you’ll eat that next bite? 

Digging in Deeper: Food (and sex) are “natural rewards.” In order for our species to survive, we need to eat and reproduce. Mother Nature made those things feel good to us so we would be more inclined to do them.

Then when we engage in those pleasurable activities, our mesolimbic pathway jumps to action to reinforce the pleasure experience and encourage repetition. 

To sum that all up: Sugar makes you feel happy, lowers your inhibitions, and nags you to do it again (!!)

Unfortunately, repeated consumption of sugar changes the availability of dopamine receptors in both the midbrain and frontal cortex. Specifically, consuming sugar increases the concentration of D1 (a type of excitatory receptor) but decreases D2 (another type of receptor), which is inhibitory. In other words, the more sugar you eat, the more you’ll need to achieve the same pleasure or “sugar high.” 👎😫 


When sugar activates the brain’s reward system, it isn’t activating one pleasure area but TWO: sweetness and the need for calories. (Hang on, I swear I’ll get to the good news). 

Recently, researchers discovered these two rewards traveled along different brain circuitry. While sweet taste is processed in the ventral striatum, nutrition (including calories) is processed in the dorsal striatum. Both are part of the brain’s reward system, but the dorsal striatum activates motor behavior where the ventral striatum does not.

What does this mean? Two things: #1 The biggest being that the supposedly motor part of the brain is not really completely motor (exciting news for neuroscientists, but admittedly not super helpful info for is) but #2 that the motor part can play a role in generating new behaviors that respond to rewards in the environment (THIS is the good news).

This means that we can use the dorsal striatum and motor behavior to help us help ourselves---WE CAN HACK THE HIJACK! 

Which is what I’m going to share with you tomorrow 👩‍🔬🔬

I’ll show you HOW you can “hack the hijack.” 

I hope by now you can see that you are not “weak” or lacking self-control. Your brain is literally being hijacked by sugar. 

Seeing how sugar activates TWO pleasure centers in the brain AND that it can literally control your body, brain, and behavior (more on this tomorrow) while also lowering inhibitions shocked me. 

YET, this knowledge also allowed me to make peace with myself for all the times I overate on desserts and/or found it incredibly difficult not to finish the whole ice cream, even if I was full. 

I hope by sharing this science with you, it will bring you some harmony, too. 🤗


P.S. (one more nerdy share) We prefer sweet over other tastes (like sour and bitter) because, evolutionarily, our mesolimbic pathway reinforced sweet foods. For example, when our ancestors were scavenging for berries, sour meant “not yet ripe,” bitter often meant “alert – poison!” and sweet meant “healthy source of fuel (carbohydrates).” It really, really, really isn’t “you” 🤓

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