In most mammals, including humans, the perception and the appreciation of sweet taste (as opposed to other tastes: salty, bitter, spicy, etc.) is an innate capacity. It depends on receptors located on the tongue. The stimulation of these receptors by sweet-tasting foods or beverages generates a sensation that most of us find intensely pleasurable. Nothing wrong with that, except that experience shows that we tend to overindulge in yummy sugary-flavored recipes…
High-sugar meals trigger bouts of hyperglycemia (“sugar rushes”) that in turn trigger a strong insulin surge, followed by spells of reactive hypoglycemia, complete with sleepiness and slight depression. You then allow yourself a small treat, in order to boost your morale… thus entering a vicious circle as nefarious for your figure as for your metabolism. When your pancreas (the gland that produces insulin) is ceaselessly stimulated by sugary foods, it will in time lose its sensitivity to glucose. Then comes insulin resistance, which is the first step towards prediabetes and, later on, type 2 diabetes. This is how the excessive pursuit of gustative pleasure contributes, along with other factors, to the current obesity and prediabetes epidemic.
The overconsumption of sugary foods has long been compared to drug addiction, but until very recently, this parallel was based more on anecdotal evidence than on scientific grounds. Recent studies on rats have however revealed that rodents can develop a real addiction to refined carbohydrates, and alterations in the reward circuit similar to those displayed by drug addicts. But can a “sweet tooth” pave the way to a genuine addiction, in the medical sense of the word?
Addiction: a definition
Etymology reminds us that the word “addiction” comes from the Latin ad-dicere, “declare to.” Roman slaves were “declared to” their master and in the Middle Ages, insolvent debtors were called “addicted” and as such subject to “enforcement by committal” (aka imprisonment for debt). This more or less matches the modern meaning of addiction according to psychoanalyst Joyce McDougall, author of a global theory of addiction, for whom a person subject to addiction is a “slave to the sole means for her to escape mental pain.” Only the object of her addiction is able to help her endure her psychic pain and unbearable emotions.
Although it gives no definition of addiction per se, the Diagnostic and Statistical Manual of Mental Disorders DSM-IV-TR does define the criteria for “substance dependence”as“three or more of the following, occurring at any time in the same 12-month period:
– Tolerance, as defined by either of the following:
• A need for markedly increased amounts of the substance to achieve intoxication or desired effect;
• Markedly diminished effect with continued use of the same amount of the substance;
– Withdrawal, as manifested by either of the following:
• The characteristic withdrawal syndrome for the substance;
• Taking the same (or a closely related) substance to relieve or avoid withdrawal symptoms;
– Taking the substance often in larger amounts or over a longer period than was intended;
– Having a persistent desire or unsuccessful efforts to cut down or control substance use.[1]
Is sugar more addictive than cocaine?
In a study conducted by French Research Council (CNRS) in Bordeaux’s Serge Ahmed on rats, among the animals supplied with a choice between drinking sugared water and self-injecting cocaine, 94% chose sweetened water! And this predilection remained in 90% of rats already accustomed to cocaine for a long period of time. This means that intense sweetness can surpass cocaine reward, even in drug-sensitized and -addicted individuals and therefore that sugar might be potentially more addictive than cocaine.
One explanation: in most mammals, including rats and humans, sweet-taste receptors evolved in environments poor in sugars and are therefore hypersensitive. Indeed, sugar remained a luxury up to the end of the 19th century. A few decades later, it invaded our kitchens and our meals. That’s too short a span for our organism and our receptors to adapt. The over-stimulation of our sweet receptors by modern Western foods might generate “a supernormal reward signal in the brain, with the potential to override self-control mechanisms and thus to lead to addiction[2].”
Neurobiologically speaking, both sweet-tasting foods and drugs stimulate dopamine signaling in the ventral striatum, a brain signaling pathway involved in the reward system. Neuroimaging studies show adaptations in the brain of obese individuals that mimic those observed in drug addicts. And when rats used to a high-sugar diet were given naloxone (an opiate antagonist), they exhibited behavioral and neurochemical symptoms akin to those generated by opiate withdrawal: the overconsumption of sugar-sweetened recipes may induce a bona fide addiction. And this absolute preference for sweetness over cocaine, even in drug-addicted rats, leads one to wonder whether sugar might be not only a drug, but the most addictive of all drugs!
Sugar addiction probably develops in infancy and childhood along with the (bad) parental practice of using highly refined carbohydrate products such as sodas, sweets, chocolate bars, and ice cream to reward or comfort their offspring. Or, on the contrary, to deprive them from dessert when they are naughty!
All this means that repeatedly snacking on sugary foods amounts to feeding your “drug habit”, not to mention the need to use more and more sweeteners to sense “sugary” tastes… Therefore your best option is to gradually wean yourself off sweet flavors, including artificial sweeteners as those do help you curb your intake of simple carbohydrates, but won’t help you regain control of your sweet tooth.

[1] American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders – Fourth Edition (DSM-IV). American Psychiatric Association, Washington D.C., 1994.

[2] M. Lenoir, SH. Ahmed et al, “Intense sweetness surpasses cocaine reward”, PLoS One. 2007 Aug 1;2(8):e698.

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