VIDEO: Q&A: Why is sugar so addictive?

Periodically, Western Today is reaching out to Western Washington University faculty and staff to get their expertise on topics of interest to the community.

For today's question, we reached out to psychology professor Jeff Grimm to ask a question he's been researching for some time:

Western Today: Your research, among other things, points to the ability of sugar to be as great an addiction to humans as many hardcore drugs such as cocaine. What is it about our brains’ relationship to sugar that makes it so potentially addictive?

Jeff Grimm: “Sugar addiction” or, more generally, “food addiction” has become a fairly common term. This has been cheered by some but not by others. For example, self-proclaimed sugar or food addicts have expressed that they finally can better conceptualize their uncontrolled urges and behavior. Others, in particular some in the drug abuse research and treatment community, scoff at placing sugar along cocaine and heroin.

The truth is that both sides have reasonable arguments for and against the food addiction concept. Certainly, people develop food-related behaviors that are similar to drug addictions. Some key features include intense craving (urges), often in response to food-paired cues, impulsive consumption of food, and eating certain foods or amounts of foods despite negative health consequences. Some rat studies have also identified a physiological withdrawal state following excessive sugar consumption similar to withdrawal from heroin. On the other hand, the psychoactive effects of food do not parallel the intense high of many drugs of abuse nor the wide variety of other effects specific to some drug classes such as pain reduction (opiates) or anxiety and paranoia (psychostimulants such cocaine and the amphetamines).

It is difficult to ignore the commonalities between food and drug addiction, however. As noted above, a key feature of both is the intense craving, impulsive behavior, and intake/administration despite negative health consequences. Focusing on these core features, an answer to what is it about our brains’ relationship to sugar that makes it so potentially addictive is then that sugar (and likely highly palatable foods containing combinations of sugar, fat, and salt) and drugs of abuse affect the same brain circuitry that has been selected for through the course of evolution to impress upon an individual the importance of stimuli in the environment that will promote survival (food, water, social interaction, reproductive opportunity) and further, promote learning to facilitate future interaction of the individual with those stimuli.

For example, a rat comes across a chocolate chip and consumes it. The rat will likely keep returning to that location several times seeking another chip. The same would be observed with a drug—if the rat had the opportunity to drink a solution containing morphine they would likely return to that location seeking the morphine.

In either case, the “addictive substance” (chocolate chip or morphine) is not a stimulus the brain evolved to detect and direct behavior towards. Highly sweet (and fatty and salty too) foods and drugs affect this survival circuitry in a way markedly beyond what the circuitry evolved to come into contact with, as it evolved before concentrated sweets and drugs of abuse became commonplace. This has led some researchers to suggest that highly palatable foods and drugs of abuse “hijack” the normal pro-survival circuitry in the brain. A reasonable conclusion is then that the foods and drugs just do this to a different degree. They are both addictive, but along a spectrum of addiction.