Addicted to Food: When sugar and processed foods take over the brain

Some people depend on opioids or methamphetamine (or both), while far greater numbers of individuals in the United States and worldwide depend on sugar and highly processed foods to feel better or even normal. We’ve known about food addiction for some time; for example, in July 2007, Yale University brought together 40 experts on nutrition, obesity, and addiction to discuss the addictive potential of foods. Nora Volkow, M.D., director of the National Institute on Drug Abuse (NIDA), then and now discussed commonalities in brain reward mechanisms related to compulsive eating as well as drug abuse. This conference is now called the Yale Historic Conference on Food and Addiction.

I asked University of Michigan Professor Ashley Gearhardt, Ph.D., a pioneer and leader in the field of food addiction and co-editor (with me and others) of the 2024 edition of Food and Addiction: A Comprehensive Handbook, what she remembered about the conference. She said, “The Yale Conference on Food and Addiction was a huge step in setting the field up to be seen as a viable and important area of study. Since that time, there have been over 400 articles and multiple meta-analyses that find that applying an addiction perspective to excessive intake of highly rewarding foods is valid and clinically significant.”

We know that drugs of abuse compete in the brain for the same drug-reinforcement sites as pleasurable-hedonic or highly reinforcing foods. The global obesity epidemic (“globesity”) is a major cause of disability, illness, and premature deaths worldwide. For years, researchers have theorized that the overeating-obesity epidemic was primarily caused by a sedentary lifestyle, and, consequently, the main solution was to exercise more. Others have suggested that the problem is not the lazy patient and instead lies with the taste, palatability, variety, addictiveness, and ease of buying and consuming manufactured foods.

The physician founder of Kellogg’s Corn Flakes, Dr. John Harvey Kellogg, was a health food and granola advocate. Dr Kellogg did not add sugar to his cereals. However, the addition of sugars to Kellogg’s breakfast cereals after his death drove up consumption of the products. Similarly, when Robert Cade, M.D., at the University of Florida, invented an oral fluid to replace sweat and electrolytes lost in exercise or sports, sales were initially flat. The addition of sugar turned the Gator football team’s secret hydrating weapon into Gatorade.

Added sugar often increases sales of drinks and foods, as it makes products more likely associated with loss of control. Lay’s potato chips captured the truth when it introduced its slogan: “Betcha can’t eat just one.” The potato chips became an international business success.

What happens is that some processed foods stimulate their own consumption and, consequently, are eaten to excess. They are also major factors in the obesity epidemic. When people consume new and/or highly reinforcing foods, the brain’s dopaminergic system, involved in rewards, takes over.

It is also true that drugs of abuse generate more brain excitement and change when taken on an empty stomach. As well, overeating and a feeling of satiety reduce illicit drug reinforcement. Drug withdrawal and a craving for drugs can be decreased by sugar. Scientists studying sugar and high-fructose corn syrup have reported that they act like drugs of abuse in classic addiction-liability laboratory studies.

My past laboratory research has shown that amphetamine, cocaine, tobacco, and even secondhand smoke cause loss of weight and appetite during consumption. They also cause increased appetite and weight after a person becomes dependent on the substance or tries to withdraw from it.

Highly processed foods (HPF), or ultra-processed foods, are extremely popular. Unprocessed foods are foods such as fruits, vegetables, and unsalted nuts. HPFs may have many added ingredients, as well as artificial colors and flavors—sugar, salt, and oil. Some experts have reported that HPFs, such as cookies, cakes, and fast food, generate up to 58% of the calories consumed in the United States. The addictive potential of HPFs may be key to the high public health costs associated with a food environment dominated by cheap, accessible, and heavily marketed HPFs.

Some medications are prescribed to treat dependence on alcohol or opioids as well as overeating behaviors. This suggests that the same underlying addiction-related brain changes cause the disorders. For example, the medication Contrave is a combination of the antidepressant bupropion and the opiate-antagonist naltrexone. Well-designed studies have shown that treatment with the drug can cause weight loss of about 1-2 pounds a week, as long as the pharmacological intervention is used with lifestyle, exercise, and diet changes. Naltrexone is also approved by the FDA for treating alcohol use disorders (AUDs) and opioid use disorders (OUDs).

Bupropion is a dopamine-augmenting antidepressant approved by the FDA for cigarette smoking cessation. So, bupropion combined with naltrexone to treat obesity suggests some overeating and weight gain is due to an underlying addiction-like disorder.

Another example of a medication used in weight loss is the combination of phentermine and topiramate (Qsymia). Phentermine is a stimulant. Topiramate is used in treating alcohol use disorders and reducing the amount of alcohol consumed. In addition, topiramate is used in treating binge eating and substance use disorders, as well as seizure disorders. Before the development of GLP-1 medications such as Ozempic, the anti-addiction medications offered the best alternative to bariatric (weight loss) surgery.

By far, the most blockbuster news in obesity treatment is the invention of GLP-1 inhibitors (think Ozempic) for treating type-2 diabetes. The drugs induced remarkable weight losses in many patients, eventually leading pharmaceutical companies to sell the drugs without insurance coverage as obesity treatments.

The efficacy of these new medications supports the idea that obesity is caused by a biochemical difference rather than a self-control weakness. This discovery could lead to a change in the perception of obesity as a chronic illness with biological and environmental causes, which, in turn, could also reduce the stigma of being overweight.

GLP-1s are also being tested in behavioral addictions like gambling and, additionally, seem to reduce alcohol consumption. Ozempic, Wegovy, and other GLP-1s may interrupt the attachment and even desire to consume drugs—just like they reduce but do not eliminate eating. These medications interrupt loss of control and bingeing.

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At Michigan, Ashley Gearhardt is studying these fascinating weight loss medications. Using the Yale Food Addiction Scale (YFAS) she helped develop in 2009, she can select patients who exhibit addiction-like behavior with food.

Says Dr. Gearhardt, “I think of the YFAS as measuring a substance addiction with the substance being highly rewarding, as with processed foods. We are starting to work on this, but a new study came out that suggests GLP-1s may be an important treatment avenue for addictive, highly processed food intake.”

The 25-item Yale Food Addiction Scale is widely used by researchers, with some clinicians using shorter versions. There are also variants for children and teens.

For many addictions, such as to alcohol, opioids, or tobacco, users are weaned from the drug. In addition, symptoms of abstinence withdrawal are treated, as are cravings and relapses.

Food addictions require slow detoxification. Dr. Gearhardt recommends encouraging people to eat three meals per day with one or two snacks of minimally processed foods (such as fruits, vegetables, intact whole grains, legumes, unsweetened dairy, lean meats, and nuts). But she knows it can be hard to do by oneself. “We work with meal delivery companies that deliver convenient, tasty, minimally processed meals that can help people reboot. For example, we are collaborating with the company Fresh N’ Lean to help people who are depressed to eat more nourishing foods.”