The Science of Sugar Addiction

The Science of Sugar Addiction

By Dr. Amanda Wiggins, owner Clean Mixes 

I’m very proud to call myself the owner of Clean Mixes.  But in what feels like a different life, I was previously a Neuroscientist. 

As the saying goes, “once a Neuroscientist, always a Neuroscientist”.  I’m a total science geek at heart and I still keep an eye on the latest brain research.  The research area I’m most passionate about is how the food we eat affects the health of what is arguably our most important organ, our brain.

Science has come a long way since I completed my Bachelor with Honors degree at the University of Otago.  I completed my PhD in Melbourne and worked as a Neuroscientist at USCF in San Francisco too.

During those years, there was very little knowledge of the gut-brain connection, and no teaching on the connection between diet and brain health.

Fast forward to 2021 and we now know that our gut health and its micro-organisms are central to our overall health.  What we eat has a huge impact on brain function, affecting everything form alertness, cognition, memory, mood and even brain volume (i.e. the amount of brain tissue we have!!).

When it comes to sugar, every way you look at it, the news is bad.  On a population basis, people who consume higher amounts of sugar tend to have more problems with dental decay, metabolic issues, obesity, and diabetes.  These are the established facts.

If you thought that was bad, there is more to the story of sugar’s negative impact on health.  Did you know that high sugar consumption can lead to both immediate and long-term brain changes?  

There are serious questions about why, as a society, we now eat more sugar per capita than ever before.  The negative health implications are obvious.  So that begs the question, why can’t we just say no to the sweet stuff?

Neuroscience has part of the answer.  Brain imaging and biochemical studies now show conclusively; sugar is highly addictive.

In this blog, we’ll shed light on why it’s so hard to just say no to sugar and give you some tips about how to reduce your sugar intake in world where sugar-laden treats are readily available.

Sugar and Addiction

Research published in the American Journal of Clinical Nutrition compared the effects of eating a low GI meal versus a high GI meal.  The meals were matched for total calorie content.  Foods that are high GI convert faster to glucose in the blood stream, resulting in a more rapid rise in blood sugar, faster need for insulin, followed by a much lower blood glucose 3-5 hours after the meal. 

The researchers found that compared with eating a low GI meal, a high GI meal elicited stronger brain activity in regions involved in eating behaviour, reward, and craving[1]

In another study, researchers found that sweet foods can be more addictive than cocaine[2].  In this study, which was conducted on animals, intense sweetness provided a stronger reward than cocaine, even in those that were already sensitised and addicted to cocaine.

The researchers noted high sugar consumption has “the potential to override self-control mechanisms and thus to lead to addiction”.

A highly cited study in the journal Neuroscience & Biobehavioral Reviews[3] found that sugar meets the criteria for a substance of abuse and may be addictive to those who binge on it.

Mechanisms of Sugar Addiction

Studies on brain activity have provided evidence that sugar consumption stimulates the brain’s rewards system, leading to further sugar consumption.  This is the same process that underlies so called ‘tolerance’ associated with addiction.  Tolerance is when you need to consume more of the substance you’re addicted to, to get the same level of satisfaction from the ‘hit’.

The mechanisms underlying tolerance involve the neurotransmitter dopamine.  When pleasant behaviours or substances causes an excess release of dopamine, you feel a pleasurable “high” that you are inclined to re-experience, and so repeat the behaviour.

As you repeat that behaviour more and more, your brain adjusts to release less dopamine. The only way to feel the same “high” as before is to repeat the behaviour in increasing amounts and frequency.

Some of the neuronal changes associated with high sugar intake include changes in dopamine activity in the part of the brain that is strongly associated with addiction (the nucleus accumbens) and also changes in opioid receptors.  Indeed, there is a lot of scientific evidence that sugar and opioids (such as cocaine) affect the same brain systems[4].  

In one fascinating study[5], researchers used brain imaging to compare the brains of lean and obese teens after consuming sugary drinks.  The results were astounding in that the brains of obese teens responded differently to the brains of lean teens. 

The study found that after drinking sugary drinks, obese teens had impaired activity in their prefrontal cortex – this is the part of the brain we use for making conscious decisions.  That means their so called “executive” thinking was impaired.  They literally couldn’t think straight.

In addition, after drinking sugary drinks, obese teens felt hungrier, whereas the lean teenagers did not feel an increase in hunger. 

The obese teens also had much stronger activity in the ‘pleasure’ centres of their brains, compared to their lean counterparts.  Together, these brain changes told the obese teens to keep drinking more, whereas this did not occur in those teenagers who were lean.

So what does this all mean?

We live in a world where heavily sweetened foods are readily available.  The double whammy is that high sugar foods are often also low in overall nutritional value, being low in things like fibre and protein.

Neuroscience has now conclusively proven that consuming highly sweet foods is addictive – possibly more addictive than cocaine!  Even worse, for those that become obese, evidence suggests that your brain may be wired to keep the weight on by responding differently to sugary foods to encourage the person to keep eating more sugar.

That’s a very difficult cycle to break!  We certainly don’t have all the answers in terms of how to break the cycle of sugar addiction, but we do know that some behaviours are likely to be helpful for eating a balanced diet.  For example:

  • Plan your day and your week. If you are susceptible to sugar cravings, understand when they might strike.  Have healthier food on hand!  Check out our FREE Weekly Planner Download.
  • Do a pantry audit and THROW OUT high sugar foods that might derail your health or eating goals. See the results of our pantry audit for tips.
  • Food swaps! Swap high sugar, nutritionally poor foods/drinks for healthier alternatives.  Instead of lollies, have something that is still sweet, but gives you better nutrition, such as a piece of fruit or a bliss ball.
  • Get your whole family or household on board with your goals. Research has proven that we are more likely to achieve success in our goals if we have the support of those around us.