Sugar has as much addictive potential as alcohol or cocaine.

Sugar may have drug-like effects in heavy users and obese people. But researchers are divided.

Why it's important

Because food can activate the pleasure center, as does alcohol or cocaine, the idea that sugar could be a drug has made its way. A 2008 study that became famous even showed that rats preferred sugar water to cocaine. However, according to two recent meta-analyses  sugar is not strictly comparable to a drug because its "addictive" potential is due to its good taste and not to its neurochemical effects as such (inducing a craving). According to these researchers, like all other palatable foods, sugar-rich foods stimulate the release of dopamine in the brain, so the addictive effect would not be specific to sugar.

Nevertheless, this  point of view is not shared by all researchers like Serge Ahmed (CNRS, Paris) for whom fructose can have effects similar to those of drugs . Not to mention the fact that "hard" drugs do not systematically provoke withdrawal and withdrawal symptoms, since the psychological environment also plays a very important role in the appearance of addictions. 

Ce que disent les études

A study published in the journal Diabetes confirms that the debate about the addictive potential of sugar is not over. According to its results, glucose and fructose, but especially the latter, would have drug-like effects in obese people. As a reminder, saccharose, the table sugar, is made up of a molecule of fructose and glucose. Fructose is found naturally in fruit (hence its name), while free glucose is rare in nature, but is present in processed products, often in the form of glucose-fructose syrup, also called isoglucose.

Researchers used MRI to observe the effects of glucose or fructose ingestion (during and after) on the brains of 14 thin and 24 obese adolescents. In all the adolescents, fructose (a sugar component) stimulated activation of the ventral striatum, also known as the motivation center. This effect was not observed with glucose. 

In slim adolescents, glucose and fructose activated the prefrontal cortex, which is involved in self-control but does not act on the part of the brain that manages appetite, located in the hypothalamus. At the same time, the level of ghrelin (the hunger hormone) decreased rapidly. On the other hand, in obese adolescents, glucose and fructose inhibited the prefrontal cortex and increased the activity of pleasure or reward centers. Also, ghrelin levels decreased more slowly, which was associated with activation of the thalamus, hypothalamus, and hippocampus. 

These results suggest that obese adolescents show abnormal metabolic and cerebral reactions after the ingestion of glucose and fructose. According to the authors, these abnormal reactions are due to their chronic over-consumption of glucose and fructose.  But is this sensitivity to sugar due to obesity as such or to over-consumption of sugar? 

Looking at the studies, we can see that many of them report that over-consumption of sugar is one of the major causes of the increase in obesity in the world, including a recent study carried out in 170 countries . A study published in 2016 reports that regular and abundant sugar consumption would gradually cause a decrease in dopamine receptors in a similar way to drug exposure. This would then cause withdrawal symptoms or depression. 

In a study published in October 2018 in the journal Appetite, researchers show that sweetened beverages, in addition to being harmful to health, can be addictive. In many countries, sweetened beverages are the most important source of added sugars in the diet.

25 young people aged 13 to 18 years old who consumed at least 3 sweetened beverages per day participated in this study. The adolescents, all overweight, were instructed to consume their usual sweetened beverages for 5 days and then to stop for the next 3 days.

During the abstinence period, adolescents reported several specific withdrawal symptoms: including headaches, increased cravings for smoking, decreased motivation to work, lack of satisfaction and ability to concentrate, strong cravings for sweetened beverages, and decreased general well-being. 

The omnipresence of these sweetened beverages and the strong advertising of these products to young people therefore poses a real public health problem. Since the 1950s, the consumption of sweetened beverages has increased fivefold among young people and adolescence is a period that is conducive to addiction. Moreover, obesity has increased the most among young people.

However, if it turns out that sugar has addictive potential, this is also the case with junk food and foods that are very rich in taste (rich in Maillard compounds, fat, salt, glutamate, etc.) and light drinks.

  Thank's you for reading this article.