Right now, scientists are actively debating whether highly processed foods are addictive and whether this contributes to our continued failure to reduce obesity and diet-related disease around the globe. Two experts share their perspectives from different sides of the debate: Dr Ashley Gearhardt contends that these foods are addictive, while Dr Johannes Hebebrand argues that “food addiction” is not responsible for obesity rates.
Highly processed foods are addictive
Dr Ashley Gearhardt: In our society, there is widespread knowledge that excess consumption of highly processed foods—like chocolate, pizza, and pastries—contributes to excessive weight gain and poor health. Millions of people try to cut down on highly processed food intake every year, but few find lasting long-term success. People fail to change their diet even when they are facing severe negative health consequences, like amputations, blindness, and early death. As highly processed foods spread around the globe, we see rates of obesity and disease rise with them.
What is it about highly processed foods that causes such a public health threat? Why are people unable to quit even when they are highly motivated to do so? Evidence is growing that highly processed foods are capable of triggering addictive processes akin to addictive drugs like tobacco. Our brains are designed to find high-calorie foods rewarding to ensure we survive the periods of famine. Carbohydrates (like sugar) and fat are high in calories and trigger the release of feel-good chemicals in the brain. For much of human history, the best hit of sugar we could hope for was finding some fruit. Fat would come from hunting down an animal or finding some nuts. While our brains are still in the Stone Age, the food industry has become skilled in jacking up carbohydrates and fats to unheard of levels and combining them with scores of additives to create unnaturally rewarding foods. These highly processed foods trigger reward responses in the brain that far exceed the levels associated with naturally occurring foods.
Addictive drugs and highly processed foods are created using very similar processes. For example, humans refine and process a naturally occurring substance (like a tobacco leaf) and process it into a product (like cigarettes) that has unnaturally high levels of a rewarding substance (like nicotine) and then add scores of additives (like ammonia and menthol) to further enhance it. These addictive drugs hijack the same reward centers of the brain that are so powerfully activated by highly processed foods. In fact, highly processed foods and addictive drugs are often consumed for the same reason—to experience a sense of pleasure and to reduce negative emotions. Whether it is a highly processed food or a drug, a substance can become so highly rewarding that it can trigger compulsive behavior (i.e., the person can’t stop even if they really want to). This is good news for industries that profit from selling these substances, but bad news for the rest of us.
Highly processed foods are not addictive
Dr Johannes Hebebrand: The food industry thrives on selling its products. In an attempt to increase sales, thousands of novel food products are marketed annually. Foods need to be tasty and must in some way fulfill a market niche. A sufficiently large number of people need to be attracted to a specific food for it to stay on the shelves of a supermarket. Obviously, a cheap price guarantees a potentially large market. The operations of the food industry depend on cultural, social, economic, legal, regulatory, and political factors.
Should we use the term food addiction to explain overeating and obesity? Most people with obesity would definitely not view themselves as food addicts. Only a subgroup would answer affirmatively. Yes, they experience “grazing,” food cravings, and binge eating attacks, and cannot stop eating despite experiencing negative health implications and negative social consequences. They may report an eating behavior suggestive of tolerance and experience withdrawal symptoms.
But exactly to what are they addicted? There is no clear-cut evidence for one or more substances in food that elicit(s) a reward comparable to that achieved upon legal or illegal drug use. Try a limited amount of any drug—let’s say you deeply inhale cigarette smoke or drink a half a glass of wine. You will quickly experience an alteration in the way you experience yourself and your environment. This rapid onset, which if rewarding may represent the first initial step in the development of a drug addiction does not occur upon ingestion of food. People who view themselves as addicted to food will resort to many foods. They will not develop an addiction to a single food.
Why then do some people state that they are addicted to food? People with obesity require more food than others to maintain their body weight. They encounter difficulties in maintenance of a reduced body weight, which may be experienced as “food addiction.” Other people will experience a strong urge to overeat upon experiencing stress, anxiety or depression. Obesity usually runs in families with genetic factors accounting for the familial loading. In conclusion, the need or urge to overeat may subjectively be perceived as food addiction but in reality, depends on a range of genetic, physiological, social, and psychological reasons and not the intake of a particular substance.
The verdict? Further research required
Food industry practices contribute to overeating and obesity; however, disagreement remains in determining whether highly processed foods meet the criteria to be considered addictive. Future research will help inform this debate and guide next steps on the best ways to promote healthy eating.
Featured image by RitaE via Pixabay