Today I want to talk about an important issue about sugar. In part 1, I discussed how the different molecules of sugar are metabolized within the body. Here in part 2, I want to touch on the effects of sugar on our neurotransmitters. In general, the addictive qualities of sugar.
This is a huge topic, and I’m not going to cover everything about the addictive qualities of sugar and ultra-processed food in general. However, this will give you a good start to understand why some of the things you eat are difficult to stop eating once you start!
Many different research experiments point to the fact that sugar can activate different regions of the brain, activating reward systems, affecting dopamine and opioid receptor binding, and affecting the release of neurochemicals like dopamine and acetylcholine (1).
Eating anything sweet will release the feel-good neurotransmitter dopamine, forging a link between eating sugary foods and enhanced mood and well-being; however temporary before the sugar high becomes a sugar low. The lows can leave you feeling depressed, listless and ‘down’, so a person will give themselves a ‘pick-me-up’, usually in the form of a sweet treat.
An interesting study published in the journal Biological Psychiatry in 2013 titled, “Dual roles of dopamine in food- and drug-seeking: the drive-reward paradox,” shows that dopamine produces both a drive for that feel-good factor and a physical need for further reward (6).
Responses similar to drugs
The reward from sugar appears to surpass that of even cocaine (2). In the study, 94% of rats who were allowed to choose between sugar water and cocaine chose the sugar. Even rats who were addicted to cocaine quickly switched their preference to sugar once it was offered as a choice. The rats were also more willing to work for sugar than for the cocaine, a ‘reward’ system which made them crave the sugar, even more, leading to addiction, and difficulty when sugar was withdrawn (3).
Research led by a neuroscientist named Joseph Schroeder of Connecticut College showed that sugary foods stimulate a person’s brain in exactly the same way that drugs such as morphine and cocaine do. They found that Oreo cookies activated significantly more neurons than cocaine or morphine (4).
A study of the highly addictive quality of high fructose corn syrup was led by Dr. Francesco Leri of University of Guelph Ontario, Canada. This study showed that consumption of high fructose corn syrup can cause behavioural reactions among laboratory rats which are similar to the effects of using addictive drugs (5).
In the same study, researchers showed that laboratory animals and humans have the same kind of vulnerability when it comes to developing a preference for high-sugar foods and for any other addictive substance.
The more animals in another experiment consumed sucrose, the more dependent they became. There were delayed acetylcholine satiation responses, causing the animals to drink even more sucrose than at the beginning of the experiment. The results were similar to that of drugs of abuse (7).
This means that for a person to experience that same feeling of “high”, they would need to consume more sugar or more drugs the next time around.
It’s been ingrained into us
Parents would bribe us with dessert if we ate all our food. We would get a sweet treat if we were ‘good’. No birthday seems complete without a cake, or cupcakes, to the point where many schools in the US started to ban them, and birthday celebrations in general, over alarm at the growing rate of obesity amongst young people, currently around 33%.
Holiday seasons, such as Halloween, Thanksgiving, Christmas, Valentine’s, and Easter, feature sweet foods from candy and desserts to sweet potato casserole, stuffing, pumpkin pie, cranberry sauce and other high-carb foods. North Americans take the best of nature’s bounty and douse it in HFCS, white sugar or brown sugar. Holidays are supposed to be a happy time, so these special foods are equated with feeling good and rewards.
That reward mentality spills over into daily life. If we work hard, we often reward ourselves with food, such as a snack, a take-out meal on the way home, ordering in, or dining out. Many of these foods have hidden sugar and/or artificial sweeteners.
Modern diets are much higher in sugar, High fructose corn syrup (HFCS), and foods that might seem to be healthy forms of sugar, such as honey, than our ancestors. The abnormally high stimulation of our tongue receptors due to our sugar-rich diets generates excessive reward signals in the brain. These excessive signals have the potential to override normal self-control mechanisms, and thus lead to overeating of sugar and from there to addiction.
Studies have proved that sugar can activate similar reward mechanisms similar to other addictive substances. However, sugar consumed on its own doesn’t necessarily contribute to weight gain and obesity. What does tend to result in significant increases in body weight are the combination of sugar and fat consumed in combination (8).
Registered Dietician Joy Kiddie explains the results of a recent 2018 study, explaining that when carbohydrates (such as sugar) and fat appear in the same food together, the results in a “supra-additive effect”, resulting in a much bigger feeling of reward being produced (9).
The study even found that people were willing to pay more for foods that combine both carbohydrates and fat together, than for foods containing only sugar or only fat.
This combination of fat and sugar or carbohydrates together is one important aspect of the creation of what are called hyper-palatable foods. These foods are highly refined and processed, with combinations of sweet, fat, salt, and flavour enhancers together. They not only light up reward system pathways in a much more significant way than any one food alone, but they have been shown to cause significant addiction-related changes, such as tolerance and cue-reactivity (10).
I will go into more detail about these hyper-palatable foods in another post and discuss the concept of the Bliss point. Needless to say, food manufacturing companies are aware of the addictive nature of hyper-palatable foods and work hard to find the exact mix of sugar, fat, salt, and flavour enhancers that will stimulate our reward centers in such a way that will leave us wanting to eat more and more of their product.
This is why awareness is key. The more you can become aware of the effect of foods in your body and to your thoughts and actions, the more you can make better choices for yourself. The first step towards positive change is always awareness.
What to do?
If you think that sugar and hyper-palatable foods might be affecting your food choices in a negative way, there are simple ways you can adjust your choices and behaviour to improve your situation.
The first step I always suggest is to pay attention to how much sugar is in your beverages. So many drinks these days contain an extraordinary amount of added sugar, including soda, iced tea, vitamin water, sports drinks, energy drinks, specialty coffees, and more. Even fruit juice contains a large quantity of sugar, with the fibre removed, which results in that sugar being very rapidly absorbed into the bloodstream.
Look on the labels of anything you drink, and see how many grams of sugar is in one serving (and compare this to how much of the product you’re actually drinking!). Four grams of sugar is the equivalent of 1 teaspoon. So at the end of the day, add up how many grams of sugar you drank, and divide that by 4 to determine how many teaspoons you drank. You might be surprised!
If you would like more tips, suggestions, and guidance, I am offering a free ebook and mini-email course called Crack the Sugar Habit in 7 days. You will receive a very descriptive ebook, along with a brief email daily for 7 days with a bite-sized piece of information and a suggestion each day for what you can do to easily reduce your added sugar consumption, step-by-step. If you’re interested, sign up below! It’s totally free!
Sign up here for your free program:
Crack Your Sugar Habit in 7 Days
- Avena NM, Rada P, Hoebel BG. Evidence for sugar addiction: behavioural and neurochemical effects of intermittent, excessive sugar intake. Neurosci Biobehav Rev. 2008; 32(1):20-39. https://doi.org/10.1016/j.neubiorev.2007.04.019
- DiNicolantonio J, O’Keefe J, Wilson W. Sugar addiction: is it real? A narrative review. Br J Sports Med. 2018; 52(14):910-913. https://doi.org/10.1136/bjsports-2017-097971
- Lenoir M, Serre F, Cantin L, Ahmed S. Intense sweetness surpasses cocaine reward. PLOS One. 2007; 2(8):e698. https://doi.org/10.1371/journal.pone.0000698
- News Archive. Student-faculty research suggests Oreos can be compared to drugs of abuse in lab rats. 2013. Connecticut College. https://www.conncoll.edu/news/news-archive/2013/student-faculty-research-suggests-oreos-can-be-compared-to-drugs-of-abuse-in-lab-rats.html#.W1IDiC_MzOQ
- Levy AM, Marshall PR, Zhou Y, et al. Fructose:Glucose Ratios—A Study of Sugar Self-Administration and Associated Neural and Physiological Responses in the Rat. Nutrients. 2015; 7(5):3869-90.
- Wise R. Dual roles of dopamine in food- and drug-seeking: the drive-reward paradox. Biol Psychiatry. 2013; 73(9):819-826. https://dx.doi.org/10.1016%2Fj.biopsych.2012.09.001
- Rada P, Avena NM, Hoebel BG. Daily bingeing on sugar repeatedly releases dopamine in the accumbent shell. Neuroscience. 2005; 134(3): 737-44. https://doi.org/10.1016/j.neuroscience.2005.04.043
- Avena N, Rada P, Hoebel BG. Sugar and fat bingeing have notable differences in addictive-like behaviour. J Nutr. 2009; 139(3): 623-628. https://dx.doi.org/10.3945%2Fjn.108.097584
- Kiddie J. A new study explains why carbs and fat together are irresistible. 2018. http://www.bbdnutrition.com/2018/06/19/a-new-study-explains-why-carbs-and-fat-together-are-irresistible/
- Gearhardt A, Davis C, Kuschner R, Brownell K. The addiction potential of hyper palatable foods. Current Drug Abuse Reviews. 2011; 4(3):140-5. https://doi.org/10.2174/1874473711104030140