Ultra-processed food: the brain, addiction and policy

My articles

Ultra-processed food, the human brain and the next generation of nutrition policy

By Dr. Asnat Raziel, bariatric surgeon specializing in obesity treatment, metabolic health and healthy longevity; Director of the Multidisciplinary Center for Obesity Treatment, Assia Medical, Assuta Ramat HaChayal, Tel Aviv

Ultra-processed food: from a conference in Atlanta to your dinner plate

Ultra-processed food was one of the hottest topics at ObesityWeek 2025, held in Atlanta in November 2025. A special session asked whether these foods are addictive and what they do to our health. In addition, the session discussed the political battle over labeling and regulation. The main message: the problem is not just the number of calories, but the entire food environment.

What is ultra-processed food, and how much of it do we eat?

Ultra-processed food (UPF) is industrial food that has gone through extensive processing. It is usually shelf-stable and contains ingredients you would not find in a home kitchen, along with artificial flavors and engineered textures. Familiar examples include snacks, sweetened drinks, sweetened breakfast cereals, processed meats and ready meals.

Earlier estimates put the figure at up to 70% of the American diet. Today, however, we have updated data. According to a report by the US Centers for Disease Control and Prevention from August 2025, ultra-processed food supplied 55.0% of the calories eaten by Americans aged one year and older. Among children and teens, the share reached 61.9%, and among those aged 19 and older it was 53.0%.

What happens to the body on a diet based on processed food

The classic evidence comes from a controlled study by the US National Institutes of Health from 2019. The researchers admitted 20 adults to a research unit and fed them an ultra-processed diet for two weeks and an unprocessed diet for two weeks. Both diets were matched for calories, sugar, fat, salt and fiber. Even so, on the processed diet, participants ate about 500 extra calories a day and gained an average of 0.9 kg.

A new study from Virginia Tech, published in November 2025, was also presented at the conference and in the literature. In it, 27 young people aged 18 to 25 ate a diet in which 81% of calories came from processed food for two weeks, and a diet with no such food for two weeks. Across the whole group, there was no difference in how much they ate at a buffet meal after each period. However, those aged 18 to 21 ate more after the processed diet and also tended to snack when they were not hungry. In other words, late adolescence may be a particularly sensitive period.

Ultra-processed food and the human brain

How does food affect the brain? A study from the Max Planck Institute explored this question with functional MRI. For eight weeks, normal-weight adults ate a daily snack high in fat and sugar, on top of their usual diet. The snack heightened the brain’s response to food and weakened the preference for low-fat food. These changes appeared with no change in weight. In other words, the food itself “trains” the reward system.

The mechanism is well known. The combination of sugar, fat and salt triggers the release of dopamine, a neurotransmitter linked to the feeling of reward. That pleasant feeling is short-lived, so hunger and cravings come back quickly. This is also part of the explanation for “food noise,” which I wrote about in my article Food noise: the chemistry of hunger.

The silent addiction

Food addiction does not appear as an official diagnosis in the DSM, the psychiatric diagnostic manual. Still, a review in the BMJ estimates that about 14% of adults and about 12% of children meet the criteria for addiction to ultra-processed food. The researchers argue that this is a substance addiction, not just a behavioral one. They compare the pattern to tobacco and alcohol addiction: intense cravings, loss of control and continued use despite harm.

It is important to distinguish food addiction from emotional eating or binge eating. Each of them has its own treatment. Read more about overcoming emotional eating and about the hunger that starts in the brain.

Policy: a struggle between science and industry

One of the key points at the conference was a clear gap. Legislation still focuses on single nutrients such as sugar or fat, rather than on the level of processing. “The problem starts with the definition,” said one of the speakers. “If you can’t define it, you can’t enforce it.”

Nevertheless, things are moving. In October 2025, California passed the first law of its kind in the United States. The law sets a legal definition of ultra-processed food and gradually removes the most problematic foods from school meals. In addition, in January 2026 the US government published the new Dietary Guidelines for Americans under the slogan “Eat real food.” These are the first national guidelines that explicitly recommend avoiding highly processed food.

At the same time, a series of papers in The Lancet from November 2025 pointed to the food industry as a major driver of the trend. According to the authors, lobbying, lawsuits and research funding hold back regulation. They therefore call for a coordinated global response, similar to the fight against smoking. You can read more about these trends in my article on fast food and obesity.

Nutrition education starts in childhood

Children learn their eating habits at home. In my view, the main message from the conference is that nothing replaces early nutrition education. Public policy should support this, and not only through taxes or restrictions. Instead, it should create an environment that allows a real choice of natural, healthy food.

What can you do at home starting today?

Cook mostly from simple, whole ingredients, even for quick meals.
Read the ingredient list: a long list with unfamiliar names is a warning sign.
Swap sweetened drinks for water.
Keep snacks out of sight, and fruit within easy reach.
Eat together, without screens, and at a slow pace.

I wrote about the link between habits at a young age and obesity later in life in my article on childhood obesity.

The future of ultra-processed food: definition, transparency and legislation

The nutrition policy of the next generation will require a combination of brain science, public education and bold legislation. First, we need a clear legal definition of ultra-processed food. Second, we need transparent front-of-package labeling. Finally, we need limits on advertising such food to children. Steps like these could turn the fight against obesity from each person’s private battle into a true national effort.

The bottom line on ultra-processed food

Ultra-processed food affects how much we eat, the brain’s reward system and our health over the years. The data show that teens and young adults are especially sensitive to this effect. Ultimately, real change requires both personal choice and an environment that supports it. I lay out a broader framework for healthy eating in my article on nutrition for healthy aging.

The information in this article is general and does not replace personal medical advice.