Why is sugar addictive?

Picture your favorite foods, pizza, ice cream and cake.

Does it make you crave food? Why are sugary foods so hard to resist? How is sugar ingestion related to addiction?

Sugar is a general term used to describe a class of biomolecules called carbohydrates found in a wide variety of foods and drinks.  Sugars activate the brain’s reward system.

This reward system is a series of electrical and chemical pathways in the brain. Socializing, sex, and smoking cigarettes are other experiences that also activates the reward system. This reward system is/wascritical to ensure the survival of humans. This reward system likely evolved to seek out appropriate foods from our environment to maximize our chances of survival in the face of food scarcity. The scenario was common during the thousands of years as we evolved.

In today’s world, when food supply is ample, we continue to over-activate this delicate reward system resulting in a series of unfortunate events.

Which stimulates craving and increased tolerance to sugar and obesity.

The history of sugar consumption by humans!

How did sugar become such a big part of life?

Sugar is a favorite fuel of choice for our brain rightfully because it is easy to digest and quickly provides energy — remember how good we feel after eating ice cream.

Having said that, because of its addictive nature, excessive sugar consumption creates havoc in our life.

Nevertheless, like psychoactive drugs (cocaine, nicotine), sugar was only designed for people belonging to society’s top crust. In poverty and hunger driven society, celebrations were only confined within elite circles or during special occasions. People used to indulge in sugary delicacies as part of festivities.

Many years ago, sugar constituted a tiny part of our diet. Plants genetic studies suggested that sugarcane came from Southeast Asia and was inaccessible until middle age. Portuguese discovered that Brazil was a fertile land for its cultivation. It is surprising to fathom that earth has been painted red with human blood to possess this sweetwhite crystal.

Sugar War —  Government-General Vs the West India Company (WIC) was the prominent sugar fight. In 1645, one thousand Portuguese rebels unleashed a guerrilla attack on a Dutch sugar plantation defended by slaves working (Portuguese got hold of Brazil again).

Eventually, it was introduced to the Caribbean around 1647, West European appeared in the picture.  During Victorian time sugar, industry saw maximum prosperity. It’s worth mentioning that its consumption has changed tremendously in the last century. In 1900, the average person intake was 112 grams, which hasescalated to 227 grams in 2009. This is just an insane increase in its daily consumption.

Forget aboutsociety’s upper strata; now sugar has ended up as a product for mass usages. It is an inseparable part of the diet regimen of underprivileged people.

The profuse intrusion of hyper-palatable or ultra-processed or high sugar foods during the last century can be compared to alcoholic beverages or drugs in the 17th and 19th century [1]. All of them are addictive in nature. Biologically human metabolism cannot tolerate or digest foods rich in sugar. Nevertheless, in modern society, even the poorest individual can easily access sugar-dense foods. Its excessive consumption turns out to be potentially hazardous for our health.

There are two prominent reasons: a) food rich in high sugar content has drug-like addiction; b) its unregulated intake is directly related to the onset of metabolic syndrome-obesity.

What is the link between sugar addiction and the obesity epidemic?

Obesity has become one of the most significant health care burdens increasing the risk of several diseases, including diabetes, cardiovascular diseases, certain cancers, and COVID-19 infection, hence substantially reducing life expectancy. The obesity epidemic affects not only developed countries but also less developed ones. Here in the USA, one-third of the population is clinically obese (BMI>30).

Two primary reasons have been proposed to explain this growing rise in obesity: sedentary lifestyle and increased calorie intake.

Specific alteration in social-life has contributed significantly to these unhealthy changes.

Firstly, the switch from a hunter-gatherer way of life to the adoption of agriculture and animal domestication about 10,000 years ago.

Next, the Industrial Revolution allowed large corporations and restaurant chains to take over food production and supply, which resulted in a decrease in food prices and an overall increase in accessibility to foods.

Thirdly, our society’s modernization with the recent arrival of automobiles, television sets, and refrigerators has led to easy access to highly calorific foods and a sedentary lifestyle leading to the obesity epidemic. Thus, behavioural and lifestyle interventions are the primary approaches to treat obesity. Still,addictive dietary habits are challenging for most individuals.

Furthermore, the epidemic of obesity isn’t entirely explained by the increase in food access and a sedentary lifestyle. Recent studies show that sugar-rich foods are addictive and that ‘hedonic mechanisms’ (pleasure-seeking pathways) may be a significant driving factor in the pathogenesis of obesity. From an evolutionary perspective, ‘ hedonic mechanisms’ were critical for human survival. They led to fat reserves that were eventually used in emergency situations (drought etc.). However, this occurred in pre-historic times when humans had an insecure food supply and ample physical activity to counter increased caloric intake. Thus, our neurons are still programmed to eat more even though we have access to abundant food, contributing to the epidemic of obesity [2].

Why do we crave sugar?

High glycemic index foods change brain activity in two ways: a) activating sweet taste cells in the mouth and gut, b) accentuated glucose signalling in the brain, mostly in post-absorptive state-reward programming is commonly observed with drug (cocaine, nicotine) addiction. Sugary diets tend to mess up the neurobiological reward pathway. These foods can activate neural regions associated with rewards.

Non-human studies have indicated that sugar decreases dopamine D2 receptors [3]. Following which one feels compulsive to consume ultra-processed foods rich in sugar. Humans are more inclined towards the intake of sugary foods because they have similar effects to psychoactive drugs. We are very good at giving plenty of reasons to eat comfort foods like sugar. We tend to fall prey to high rewarding sensations nexus, associated with managing stress, anxiety, anger, pain, bad mood etc.

Nevertheless, this pattern is more evident in adolescent and obese women. The research suggested that sweet foods could alleviate depressive state-although it is a vicious cycle [1]. Ultra-processed foods trigger an abrupt shift in glucose and insulin levels similar to a psychoactive substance. This further stimulates the mesolimbic dopamine reward pathway, followed by a sudden increase in insulin level and a sharp decrease in blood glucose [2]. This series of physiological changes lead to sugar cravings and excessive consumption.

One in three Americans is at risk of diabetes. This data is very scary, and it has become increasingly important to fully understand the mechanism involved in sugar addiction.

It is challenging to understand sugar addiction. The biological pathways involved in this psychological behaviour are poorly understood—most of the research studies involved rats or mice. Very little information is available regarding human.

Nevertheless, pleasure-seeking behavior is the starting point for all addictions. Scientifically known as hedonic mechanisms [4]. Dopamine and acetylcholine release-as a result of consumption of pleasure-seeking foods is the most explored pathway. Even after thorough understanding, we are unable to exploit these pathways for the betterment of human health. Because the release of these neurotransmitters affects multiple biological signalling in our body.

We can be more precise about the vicious cycle of sugar addiction by understanding dopamine release and acetylcholine. Both of them are involved in the sugar reward program.

Rewards are made up of three terms: liking, learning and incentives. Dopamine (DA) release plays a vital role in appetite recognition (to eat or not to eat), whereas acetylcholine (ACh) release tells us our satiated with food. DA/ACh balance is critical not only for food consumption but for general health.

This balance is controlled by the Hippocampus (the core region in our brain, which is involved in learning or memory and in charge of eating). Perturbation in this ratio usually associated with sugar addiction’s withdrawal symptom is an integral part of sugar addiction’s vicious cycle. So how this all starts, if one is continuously consuming palatable food (the sugary ones), DA levels or its effects wanes out, leading to an increase in ACh level.

To summarize, the constant consumption of sugar sets you in a yummy rewards system.

Moreover, if one becomes suddenly aware of sugar intake and try practice restraining from it they tend to go in withdrawal, which is followed by “binge eating” – in this state person wants to go back to the same state when the drug or in our case sugar was in the system.

Then comes the “craving (can be psychological or physiological). Finally comes the “sensitization”: means one need a higher dose of sugar to carry on with life.  Before you become aware, you are already entrapped in the vicious nexus of sugar addiction.

Can you believe addictive drugs and palatable foods uses a common subset of the neural system? That means different external reinforcement leads to a similar reward system. Like DA, ACh has released identical to nicotine (number one addictive drug in the planet) consumption as with sugar one. Moreover, nicotine withdrawal increases ACh level and decreases DA. This evidence strongly confirms that not psychologically but at the biological level, excessive intake of sugar can be directly linked to drug abuse/addiction. This is a surprising revelation.

Are you a fat or sugar burner?

One of the biggest reasons one could not come out from the intricate nexus of sugar addiction is that we pay minimum attention to our primary energy intake source. For instance, if our primary energy source is a food rich in healthy fats, wholesome nutrients and fiber. The body does not go in extreme insulin spikes, which means blood sugar levels remain balanced-good energy level. Besides, fats with wholesome fiber keep you fuller and satiated for longer hours (4 to 6 hours). Infect during exercising fat reserves will be used as the primary source of energy.

On the contrary, precisely opposite effects are observed with diets rich in high glycemic index. Hyper palatable foods or ultra-processed food immediately spike insulin, following which sugar level drops immediately.

Insulin is an anabolic hormone that directs digested sugar into adipocytes (fat cells). This is a normal metabolic process, but the sudden increase in insulin drops blood sugar to the level that one feels more craving for sugar, besides feeling tired, hungry, agitated or irritated.

In the end, one eats more sugar to keep the optimum energy level, which leads to weight gain, loss of self-esteem. Therefore, the vicious cycle never ENDS. 

The evidence linking food addiction with commonly used addictive drugs

The word sugar addiction is not great to begin with; one would not like to identify them with this phrase.

In reality, excessive sugar consumption subjects you to diabetes, obesity and all sort of life-threatening diseases. Considering the potentially hazardous effect of sugar, it would not be over-exaggerated to compare sugar with drugs like cocaine or nicotine. This analogy has become very popular in the past few years, as most people experience sugar cravings as intense as cocaine.

Although it is a little absurd to compare drug and sugar because the latter is not behaviorally and psychologically toxic.

This explains that even if one drinks 100 ml of sugar syrup—it does not put you in any abnormal mental state (euphoria or excitement). Isn’t it hilarious you will get a ticket, or traffic police will arrest you if you are driving under the influence of cocaine?

Still, it does not bother them if you are going after eating dozens of doughnuts? Drinking half a gallon of sugar-sweet sodas is a socially acceptable norm, but not cocaine/nicotine.

Nevertheless, at the neurobiological level, considerable overlap was observed in neural substrates between sugar and drugs cravings. Both recruit the same network [1].

Both increases dopamine in a part of our brain. There is ample evidence that the neural substrate of sugar reward is more robust than cocaine.

Which further explains why most interventions were effective in treating cocaine-influenced behaviour, but very few of them were effective in treating sugar reward-driven behavior in mice and rats. This observation is really a revelation; neural substrates of high sucrose diet are more robust than cocaine. It means sugar neural substrates are sturdier to biological dysfunctions. Which makes sugar addiction more toxic and difficult to treat. It is also worth comparing nicotine and sugar, as they use the same receptor and pathway-i.e., it is so challenging to leave sugar.

It should not be a surprise to see why one gains weight suddenly when they stop smoking.

Same reward and craving cycle appears, and smokers tend to eat more. Therefore, it makes sense when sugar-fed rats given Chantix -a smoking cessation drug (nicotine agonist) led to drastic sugar consumption reduction.

Although these discoveries seem very encouraging in reducing sugar intake and eventually, the obesity epidemic. Scientists need comprehensive data about humans. There is no point in pushing drugs on people unnecessarily. Usage of similar neural circuits and robust substrates makes excessive sugar intake a never-ending cycle.

With sugar addiction, one has to deal with physical issues—an enormous psychological burden.

However, sugar is not bad for us. For instance, it is the primary fuel for our brain. Brain derives its energy from glucose, as it cannot store fuel. The vital point is moderation and mindfulness.

We are just trying to refrain you from eating that doughnut or soda with a burger for breakfast and lunch.

We trained ourselves to eat sugar the same way we can program our neurons to eat natural foods rather than processed foods with a higher glycemic index. 

Stop eating foods full of empty calories and low in nutrients—it is all about the right choices.

Read more: Ten smart ways to cut down on sugar

Written by Isha Sharma and Pankaj Kapahi, PhD

References:

1. Ahmed SH et al 2013. Sugar addiction:pushing the drug-sugar analogy to the limit. Curr Opin Clin Nutr Metab Care.16:434-9.

2. Eaton SB, Konner M 1985. Paleolithic nutrition. A consideration of its nature and current implications. N Engl J Med.312:283–9.

3. Dalai SS et al 2020. Low carbohydrate ketogenic therapy as a metabolic treatment for binge eating and ultraprocessed food addiction. Curr Opin Endocrinol Diabetes Obes. 27:275–282.

4. Weiss AD et al 2018. Sugar Addiction: From Evolution to Revolution. Front. Psychiatry.9:545.

1 reply on “Why is sugar addictive?”

  • Great knowledge. So many decades are crossed we don’t know all these facts thank you for all this information

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