Processed foods aren’t just bad, they can also be addictive.

Five years ago, a group of nutrition scientists studied what Americans eat and came to a surprising conclusion: More than half of the calories the average American consumes come from ultra-processed foods, which they defined as “industrial formulations” that include large amounts. of sugar, salt, oils, fats and other additives.

Highly processed foods continue to dominate the American diet despite being linked to obesity, heart disease, type 2 diabetes and other health problems. They’re cheap, convenient, and designed to be tasty. They are aggressively advertised by the food industry. But a growing number of scientists say that another reason these foods are so consumed is that, for many people, they are not just tempting but addictive, a theory that has caused controversy among researchers.

Recently, the American Journal of Clinical Nutrition explored the science behind food addiction and whether ultra-processed foods are contributing to overeating and obesity. The publication held a debate between two leading experts on the subject, Drs Ashley Gearhardt, associate professor in the department of psychology at the University of Michigan, and Johannes Hebebrand, head of the department of child and adolescent psychiatry, psychosomatics and psychotherapy at the University of Duisburg-Essen. , in Germany.

Gearhardt, a clinical psychologist, helped develop the Yale Food Addiction Scale, a survey used to determine whether a person shows signs of addictive behavior towards food. In a study of more than 500 participants, she and her colleagues found that certain foods were more likely to trigger “addictive” eating behaviors, such as cravings, loss of control, and an inability to reduce the amount, despite people suffering harmful consequences and a strong desire to stop eating them.

At the top of the list were pizza, chocolate, potato chips, cookie, ice cream, fries, and cheeseburger. Gearhardt found in his research that these highly processed foods have a lot in common with addictive substances like cigarettes and cocaine. Its ingredients are derived from plants and natural foods that are stripped of components that slow their absorption, such as fiber, water and protein. Then the most pleasurable ingredients are refined and processed into products that are quickly absorbed into the bloodstream, increasing their ability to “turn on” regions of the brain that regulate reward, emotion and motivation.

Salt, thickeners, artificial flavors and other additives in highly processed foods increase their appeal, enhancing properties such as texture and mouthfeel, just as cigarettes contain a number of additives designed to increase their addictive potential, Gearhardt said. Menthol helps mask the bitter taste of nicotine, for example, while another ingredient used in some cigarettes, cocoa, dilates the airways and increases nicotine absorption.

A common denominator among the most irresistible ultra-processed foods is that they contain high amounts of fat and refined carbohydrates, a powerful combination rarely seen in natural foods that humans have evolved to eat, such as fruits, vegetables, meats, nuts, honey, beans and seeds, Gearhardt said. Many foods found in nature are high in fat or carbohydrates, but usually not both.

“People don’t have an addictive behavioral reaction to natural foods that are good for their health, like strawberries,” said Gearhardt, who is also director of the Food and Addiction Science and Treatment lab in Michigan. “This subset of highly processed foods is designed very similarly to how we create other addictive substances. It’s the foods that can produce out-of-control and compulsive, problematic behaviors that resemble what we see with alcohol and cigarettes.”

In one study, Gearhardt found that when people stopped consuming highly processed foods, they experienced symptoms comparable to the withdrawal symptoms seen in drug users, such as irritability, fatigue, sadness, and cravings. Other researchers have found in brain imaging studies that people who frequently consume junk food can develop tolerance over time, causing them to demand ever greater amounts to obtain the same pleasure.

In his office, Gearhardt has encountered patients — some obese and some not — who struggle in vain to control their intake of highly processed foods. Some try to consume them in moderation, but find they lose control and eat to the point where they feel sick and upset. Many of her patients find they can’t give up these foods despite struggling with uncontrolled diabetes, excessive weight gain and other health issues.

Hebebrand, however, disputes the theory that any food is addictive. While chips and pizza may seem irresistible to some, he argues they don’t cause an altered mental state, the hallmark of addictive substances. Smoking a cigarette, drinking a glass of wine or taking a dose of heroin, for example, produce an immediate sensation in the brain that food does not, he explained.

“You can take any addictive drug, it’s always the same story: almost everyone will have an altered mental state after taking it,” Hebebrand said. “This indicates that the substance has affected the central nervous system. But we are all eating highly processed foods, and nobody experiences this altered mental state because there is no direct impact of a substance on the brain.”

For people struggling to limit their intake of highly processed foods, Gearhardt recommends keeping a journal to identify the ones that attract the most — the ones that cause intense cravings that you can’t stop eating once you start. Don’t buy these foods, and stock your fridge and pantry with healthier alternatives you like, she said.

“Habitually feeding your body the nutritious, low-processed products you enjoy can be important in helping you navigate this challenging food environment,” Gearhardt said.

Translated by Luiz Roberto M. Gonçalves.