PDF Summary:Ultra-Processed People, by Chris van Tulleken

Why is it so hard to stop eating your favorite chips? What are the implications of supermarkets containing aisle after aisle of sodas, frozen meals, and packaged snacks—and only tiny produce sections?

In Ultra-Processed People, professor and infectious disease doctor Chris van Tulleken argues that ultra-processed food—everything from breakfast cereals to fast food, candy, and lunch meats—is destroying our health and our planet. He claims that ultra-processed food isn’t really food at all; rather, it’s akin to an addictive substance that tricks us into eating more and more while simultaneously increasing our risk of developing a host of diseases. Plus, the way ultra-processed food is made harms the environment and contributes significantly to climate change.

Our guide explores van Tulleken’s arguments and his recommendations to counteract the effects of ultra-processed food. We’ll also provide context for his claims from the perspective of nutritional science, statistics, and other influential books on processed food, including The Omnivore’s Dilemma, In Defense of Food, and Fast Food Nation.

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This system comprises our stomach, liver, pancreas, small and large intestines, and other organs that transmit signals to and from the brain via various nerves, blood vessels, and hormones, constantly telling our bodies when, what, and how much to eat.

(Shortform note: The brain region involved in regulating hunger and fullness is called the hypothalamus. Its primary function is to keep your body in balance by managing many important bodily functions, including blood pressure, mood, sex drive, and sleep. This link between our systems for sleep and eating may explain the many studies demonstrating that getting too little sleep is associated with overeating and weight gain. One explanation for this could be that lack of sleep activates the hedonic aspect of eating, driving the desire for salty, sugary, and fatty snacks in particular. Conversely, a 2024 study found that diets high in UPF lead to an increased risk of sleep problems.)

Just as we have a system that governs food intake for purposes of energy and nutrition, we also have a hedonic system, part of which governs eating purely for pleasure. One theory about why we find UPF appealing is that it causes our pleasure system to override our weight regulation system. However, an increasingly likely explanation for why we can’t stop eating UPF is that it short-circuits our weight regulation system completely.

(Shortform note: Experts who fault the hedonic system for overeating say ultra-processed foods in particular trigger “hedonic hunger”—a primal drive to eat anything delectable even if we’re not hungry. They say that the urge to eat these foods is centered in the brain’s reward system, which is also involved in addiction.)

UPF Interferes With Our Internal System by Acting Like an Addictive Substance

Van Tulleken argues that UPF is an addictive substance that deceives our brain and body into eating more of it. In this section, we’ll first examine an experiment van Tulleken conducted on himself that demonstrates how addictive UPF can be. Next, we’ll look at four characteristics of UPF that trick us into overeating: softness, calorie density, added flavorings, and additives.

Van Tulleken’s Experiment on Himself Points to UPF’s Addictiveness

Van Tulleken conducted an experiment on himself to study the effects of UPF. He began by eating no UPF for a month, and then for the next month he ate a diet consisting of 80% UPF.

Van Tulleken describes how his primarily UPF diet made him anxious, exhausted, achy, and less productive. At the end of the four weeks, he’d gained 13 pounds. Tests showed that the hormones in his body that are involved in eating weren’t functioning properly:

• the hormone that signals fullness (leptin) hardly responded to a large meal,
• the hunger hormone (ghrelin) was extremely high just after he ate, and
• the hormone that signals fat storage (also leptin) increased fivefold.

In addition, MRI scans showed increased connectivity between the parts of his brain involved in desire and reward and the parts involved in hormonal control of food intake. The brain pathways didn’t change, but the information flowing through them did—and over time, those brain circuits themselves could change, too.

All of this suggested that van Tulleken’s eating was increasingly governed by subconscious signals telling him to eat more.

(Shortform note: Van Tulleken documented his experiment in video form for the BBC. The video shows that in addition to the other results, his BMI went up by two points, putting him into the overweight range, and his body fat went up by almost seven pounds. The hunger hormone in his blood increased by 30%, which explained why he felt hungrier and often kept eating even when he didn’t enjoy it.)

Besides van Tulleken’s experiment, there are many other indications that UPF is addictive, including:

• Brain imaging shows that UPF stimulates the brain’s reward system in the same way as addictive drugs.
• People consistently score UPF higher than real food on food addiction scales.
• UPF and addictive drugs are both modified from their natural state to allow for fast, easy delivery of the rewarding substance.
• A high UPF diet causes more deaths worldwide than tobacco.

(Shortform note: Critics of van Tulleken’s claim that UPF is addictive argue that for as long as there has been food, there have been food addictions. They point to sugar in particular as an example of a minimally processed ingredient that can result in addiction. Indeed, research increasingly shows that sugar may be as addictive as some illegal drugs; eating it releases dopamine and opioids in the body that lead to compulsive behavior. But the fact that sugar is addictive doesn’t undercut the claim that UPF is addictive. As van Tulleken notes, the large amount of added sugar in some UPF food may be one of the many factors contributing to its addictiveness.)

In addition, says van Tulleken, UPF has many characteristics that trick us into overeating.

UPF’s Softness Tricks Us Into Eating Faster

The chemical, physical, and heat processing UPF undergoes makes it much softer than whole foods. Softer food is easier to eat, so people eat UPF faster than other food. This means they end up eating more: Research shows that eating faster increases the risk of eating more, gaining weight, and having a metabolic disease.

Plus, our digestive system has evolved to break down the physical structure of whole foods—not to handle food so soft that it behaves in our bodies as if it’s already been chewed. The hormones that normally signal you’re full don’t know what to do with UPF. So not only is UPF’s softness causing us to eat more of it, but it’s also tricking us into not feeling full when we do.

(Shortform note: One reason UPF is so soft is that industrial processing destroys the natural fiber in foods. But fiber serves many important functions in the body. It slows digestion, reduces blood sugar spikes, delays the return of hunger after eating, and travels to the colon to nourish the microbes in the gut microbiome. As a result, people with high-UPF diets not only tend to eat more than people with diets high in unprocessed, fiber-rich foods, but they also appear to absorb significantly more calories when they eat.)

UPF’s Calorie Density Tricks Us Into Eating More

Whole foods like vegetables and meat have a high water content, but UPF needs to be dry so it doesn’t go bad. Because it lacks moisture, UPF is very dense in calories. This calorie density, when combined with softness, means that UFC will cause you to consume more calories, faster, than you would with unprocessed foods. Studies consistently show that foods with high calorie density promote eating and weight gain.

(Shortform note: In The Omnivore’s Dilemma, Pollan writes that humans have a biological preference for calorie-dense foods because our hunter-gatherer ancestors feasted whenever they could, to build fat reserves to last through future food shortages. UPF companies are taking advantage of this evolutionary preference to get us to buy and consume more.)

UPF’s Added Flavoring Tricks Us Into Thinking We’re Eating Something Nutritious

Van Tulleken says the added flavoring in UPF also tricks us into thinking we’re eating something nutritious, which may cause us to eat more. This happens because we associate certain flavors with nutritious foods, even though ultra-processing destroys the nutrients in whole foods.

When it comes to nutrition, there’s a big difference between whole foods and the components that make up whole foods. Research consistently demonstrates that eating whole foods protects against cancers, heart disease, dementia, and early death. Many studies show that nutrients like vitamins and minerals are only beneficial when consumed in whole foods containing them. When these same nutrients are consumed independently of whole foods, they’re not effective. In other words, multivitamins and supplements generally don’t work for healthy people (people without nutrient deficiencies). They don’t decrease the risk of disease or death.

(Shortform note: While experts agree that supplements are often ineffective for people without nutritional deficiencies, it’s also true that many people do have nutritional deficiencies and may benefit from certain supplements. More than two billion people worldwide are deficient in key vitamins and minerals, especially iron, iodine, zinc, and vitamin A. These deficiencies are especially prevalent in low-income countries and among pregnant and lactating women and young children. Doctors and scientists generally agree that the best way to address these deficiencies is through a healthy diet of whole foods; if that’s not possible, some supplements appear to be more effective than others. The more useful ones include vitamin B12, folic acid, vitamin D, and calcium.)

The process of manufacturing UPF destroys the thousands of molecules that comprise whole foods, removing vitamins, reducing fiber and polyphenols, and generally ridding the food of micronutrients. UPF manufacturers are required by law to add certain vitamins and minerals into their food so we don’t develop deficiencies. However, the few that they add back in don’t make up for all the micronutrients lost in the course of processing. Those lost micronutrients might be precisely the ones that make whole foods so good for you.

In addition to removing micronutrients from food, ultra-processing destroys flavor molecules, so manufacturers also add in flavoring. Van Tulleken explains that added flavorings in UPF affect both smell and taste. We link smells and tastes with our past experiences with food, so these senses can signal to us how nutritious a particular food is likely to be. This means that the added flavoring in UPF may convince our brains that what we’re eating is nutritious, even if it has been stripped of all its micronutrients. In short, added flavoring in UPF may be tricking our systems of smell and taste into thinking we’re eating something nutritious.

For example, van Tulleken notes that Pringles snack chips contain the flavor enhancers glutamate, guanylate, and inosinate—molecules that normally occur in easily digestible proteins such as cooked meats. When we eat Pringles, the added flavoring signals to our brain that we’re eating something akin to a home-cooked stew. Instead, all we get is starch and fats.

(Shortform note: Pringles fans may argue that while the snacks aren’t as nutritious as a stew, at least they contain potato. However, Pringles are only 42% “potato content,” and due to ultra-processing, they’re far less nutritious than a potato. Potatoes are a good source of potassium, vitamin C, folate, and vitamin B6, as well as many other micronutrients. Pringles contain none of those nutrients except vitamin C (in about half the amount found in potatoes). They’re also high in saturated fat and contain more calories than potatoes.)

Some scientists have theorized that we’re eating more in an attempt to make up for our increasing micronutrient deficiency. This may be why UPF diets can result in malnutrition and obesity simultaneously.

(Shortform note: Research shows that, although processing removes micronutrients from food and can’t possibly replace them all, some UPF is more nutritious than others. For example, soda is high in calories and contains no healthy nutrients, but a breakfast cereal that’s high in fiber, low in sugar, and fortified with nutrients that we might not otherwise get enough of, like folic acid, can be a nutritious choice.)

UPF’s Additives Damage Our Microbiome

Plus, additives in UPF may damage our microbiome, leading to overeating and other problems.

Our microbiome consists of all the microorganisms—such as bacteria, viruses, and immune cells—that live in our body, particularly in our gut. Van Tulleken calls the microbiome the body’s largest immune organ; it’s responsible for protecting us from harmful bacteria.

Manufacturers use thousands of additives in UPF, including emulsifiers, stabilizers, leavening agents, artificial sweeteners, and artificial flavors. Our gut microbiome turns some food into beneficial molecules, but food containing additives may harm the microbiome by leading to intestinal inflammation. This can result in overeating.

Even if additives don’t cause overeating, research suggests that they can alter the balance of bacteria in the gut. This imbalance can contribute to a variety of diseases, including rheumatoid arthritis, autoimmune diseases, and even cancer and mental illness.

(Shortform note: Van Tulleken only cites one study (on mice) linking additives to microbiome damage and overeating; critics note that human microbiomes are very different from the microbiomes of other animals. However, research linking microbiome damage to inflammation indicates that certain diets high in additives may cause chronic inflammation, which is associated with many serious diseases. Inflammation is your body’s immune response to a virus, bacteria, foreign toxin, or injury. Acute inflammation is a natural part of the healing process. Chronic inflammation occurs when your body continues sending inflammatory signals even when there’s no outside danger. Eating too much of certain UPF may increase chronic inflammation by causing a gut microbiome imbalance.)

Don’t Governments Regulate Food Additives?

Most people assume that any chemically altered substances and artificial ingredients in their food have been certified as safe by the government. Unfortunately, van Tulleken explains, that isn’t the case. In the US, for example, the Food and Drug Administration (FDA) allows food companies to “self-certify” their new additives, meaning that they aren’t required to submit any proof to the government that they’ve done testing on UPF’s safety.

How did this happen? In the 1950s, the US government became concerned about the many new industrially produced chemicals that companies were adding to food. The legislature passed a law requiring testing and formal approval by the FDA before an additive could be used in food. However, the law provided an exception for additives that were “generally recognized as safe (GRAS),” so that common ingredients like salt wouldn't have to go through the FDA's extensive approval process.

Many UPS manufacturers began using this exception as a loophole, and eventually, due to a backlog in GRAS applications, the FDA decided to allow companies to make their own determinations about whether their additives were safe. This means that UPF manufacturers don’t need to get government approval for new food additives. Not only that, but if a company does apply to the FDA for GRAS approval and the FDA expresses concerns about the safety of the additive, the company can simply withdraw its application and certify the additive's safety itself.

There are probably around 10,000 food additives in the US, but we don't even know for sure how many there are because companies that self-certify don't have to inform the FDA that they're doing so.

Addressing Problems With the Food Safety Regulation System

Many experts believe we need more regulation of UPF. Currently, very few US government policies address UPF at all. One study shows that in the approximately 40 years between 1983 and 2022, only 25 policies were proposed or passed at the state and federal level that would regulate UPF.

Comparing the FDA’s lax regulation of food with its strict regulation of drugs highlights the potential risks in the current system, given that we consume food at least three times a day, while medication use is typically more infrequent. Some nutritionists say the FDA and the US Department of Agriculture (USDA) must act urgently to make UPF safe because Americans’ unhealthy diet contributes to over 678,000 American deaths a year from chronic food-related illnesses.

Although van Tulleken recommends various forms of government regulation of UPF (described below), he doesn’t mention one of the most obvious: requiring stricter government oversight of UPF additives.

Some researchers say that the solution to the problems with the current food regulation system lies in giving the FDA more power and resources not only to approve new additives, but also to review the safety of existing additives and limit the GRAS exception.

What Are the Environmental Effects of Ultra-Processed Food?

In addition to directly harming human health, UPF also contributes to carbon emissions and environmental destruction on a massive scale.

Rather than growing many small crops for local communities, which is expensive, agribusiness focuses on four or five high-yield commodity crops, such as soy and palm oil. To make these crops profitable, companies either turn them into UPF or feed them to factory animals (and much of that meat is itself made into UPF). Investing heavily in a few commodity crops contributes to climate change in many ways, including:

1. Carbon emissions from the destruction of forests. Tropical forests, which are very good at cleaning carbon dioxide out of the atmosphere and storing it, are clear-cut and burned to grow commodity crops. This releases huge amounts of carbon dioxide into the atmosphere.

In regions like the Amazon, destroying the forest also results in less rain. (Rain in the central Amazon is caused by water evaporating from the ocean and falling on coastal forests; these forests then emit water vapor, which creates clouds that travel inland to create rain.) This lack of rain results in drought. Agribusiness in the central Amazon is not only shooting itself in the foot by altering the weather patterns that irrigate its crops, it’s also contributing to climate change: The southeastern Amazon is now a carbon source rather than a carbon sink.

(Shortform note: Forests, like oceans, are examples of carbon sinks, meaning they absorb more carbon dioxide than they release. The opposite of a carbon sink is a carbon source: a process that releases more carbon than it absorbs. All processes that use fossil fuels—such as burning gasoline, coal, or wood—are carbon sources. The Amazon rainforest historically absorbed over 1.5 billion tons of carbon a year, or 4% of all emissions from fossil fuels. Due to deforestation and fires to accommodate agriculture and cattle ranching, the Brazilian portion of the Amazon now emits 3.6 billion more tons of carbon than it sequesters.)

2. Greenhouse gas emissions from growing, processing, and transportation. Massive amounts of fossil fuels, in the form of everything from fertilizers to gasoline for farm equipment, are required to grow the crops. The machinery required for processing is also energy-intensive. And most UPFs contain ingredients from four or five continents that have to be shipped internationally many times over. These factors further contribute to emissions.

(Shortform note: In How the World Really Works, scientist Vaclav Smil points out that the amount of fossil fuels required to produce agrochemicals such as fungicides, insecticides, and fertilizers is far greater than the amount required to make and power farm machinery. This is because fertilizer is made with nitrogen, which is produced using fossil fuel. It takes 1.5 liters of diesel fuel to make one kilogram of nitrogenous fertilizer. Fertilizer, in turn, releases the greenhouse gas nitrous oxide.)

As a result, industrial food production is the leading cause of global biodiversity loss and the second largest contributor to global emissions.

(Shortform note: Studies show exactly what percentage of greenhouse gas emissions is caused by each food production-related activity. Of the approximately 26% of global emissions caused by food production, livestock and fisheries account for 31% of emissions, crop production accounts for 27%, land use (destruction of forests, grasslands, and other carbon sinks to create cropland or pasture) accounts for 24%, and supply chains account for 18%, of which transport is the highest contributor, at 6%.)

UPF manufacturers also harm the environment through plastic pollution. Coca-Cola, PepsiCo, and Nestlé are the top three plastic polluters in the world. About 90% of all plastic waste ever produced has not been recycled. It’s either burned, disposed of in landfills, or littering our public lands and oceans.

(Shortform note: In How the World Really Works, Smil makes it clear that plastic waste is only one aspect of the environmental harm caused by plastics: The process of manufacturing plastics in the first place also produces large quantities of carbon emissions. This is because most plastics are made by heating petroleum (a refined fossil fuel) at very high temperatures, which requires a lot of energy. UPF companies’ heavy reliance on plastic packaging for their foods and beverages therefore negatively affects both our climate and, through plastic waste that degrades into microplastics, the health of wildlife, people, and local economies.)

How Can We Counteract the Negative Effects of Ultra-Processed Food?

UPF is harmful and ubiquitous, but we have the power to counteract its negative effects. In this section, we first examine van Tulleken’s contention that governments should regulate UPF—not by banning it, but by taking other measures to limit its consumption. Next, we discuss his suggestion that we eat less UPF or stop eating it altogether.

Government Regulation of UPF

Van Tulleken advocates three primary methods for regulating UPF: prohibiting government policymakers from taking money from the food industry, labeling UPF products accurately, and restricting UPF marketing.

Governments Should Be Prohibited From Taking Money From the Food Industry

The food industry heavily influences government policies. Various “nutritional” foundations exist for the primary purpose of shaping food policy—and they’re funded by an array of UPF companies. Much of the research critical of the link between UPF and health problems is funded by or affiliated with companies that produce UPF.

Yet the data is clear, says van Tulleken, that when an industry funds science, the results are biased in favor of the industry. He argues that the UPF industry should be divorced from scientific research into the effects of UPF, and that government policy shouldn’t be funded—directly or indirectly—by the food industry.

(Shortform note: Van Tulleken repeatedly points out how UPF manufacturers can prejudice research and policy in their favor, yet he also acknowledges the challenges inherent in decoupling government and the food industry. This is partly because research—particularly large-scale studies on humans—is expensive, and transnational UPF companies have significantly more money available to fund these studies than many of the other relevant players. This is often the case with scientific research. According to the Organisation for Economic Co-operation and Development (OECD), more than 60% of research and development in scientific and technical fields is conducted by industry, with 20% performed by universities and 10% by government.)

Governments Should Label UPF Products Accurately

Van Tulleken argues that labeling would help the public make informed choices about what they’re buying. He points to Chile, where three-quarters of adults are overweight or obese. There, the government implemented a policy requiring labeling on food products high in calories, sugar, sodium, and saturated fat. The labeling resulted in fewer food purchases.

(Shortform note: As of 2024, 10 countries (including eight Latin American countries, Canada, and Israel) have implemented or are in the process of implementing mandatory front-of-package warning labels for certain unhealthy foods. The labels must warn about excess levels of sugar, saturated fat, and sodium; in some countries, they also must warn about excess calories and trans fats. One issue with this approach, however, is that focusing on “bad” ingredients overlooks UPF that doesn’t have an excess of these ingredients but still causes health problems as a result of the processing itself—products such as various sugar-free, fat-free candies, cookies, and salad dressings. Nonetheless, there is usually a high correlation between these ingredients and UPF.)

Governments Should Restrict Marketing of UPF

Marketing is a huge portion of the budget for most UPF. UPF companies often aggressively market their products to low-income communities, sometimes with disastrous results.

For example, in the 1970s, Nestlé targeted poor mothers in developing countries by sending saleswomen dressed as “nurses” into their communities to promote the supposed nutritional benefits of baby formula over breastfeeding. Yet Nestlé knew, or should have known, that many of these communities did not have access to clean water, forcing caregivers to mix the formula or wash the bottles with contaminated water. Nestlé’s practices were linked to thousands of infant deaths.

Van Tulleken argues that to prevent this type of predatory marketing, governments should implement rules for how companies market all UPF.

(Shortform note: In Fast Food Nation, journalist Eric Schlosser describes another way UPF companies aggressively market their products to susceptible consumers: by marketing to kids. Thanks to companies like McDonald’s, which started the practice with its Happy Meals and the Ronald McDonald mascot, by the 2000s there was an entire subset of the advertising industry devoted to fostering brand loyalty in children. UPF companies use bright colors, cartoon characters, toy and movie tie-ins, and even deals with school districts to aggressively promote and sell fast food and other unhealthy UPF to kids. Many countries now restrict marketing of junk food to kids, an approach that’s proven largely successful.)

Choosing Not to Eat UPF

It’s difficult for individual consumers to effect change on a systemic level simply by shopping differently, especially since many people in low-income communities don’t have access to non-UPF foods.

However, if you want to effect change on an individual level and have access to minimally processed foods, van Tulleken suggests experimenting with eating less UPF or cutting it out entirely. He advises going on an 80% UPF diet for a few days, armed with the knowledge you now have about how UPF affects our health. Pay attention to how you feel and whether certain foods feel more addictive to you. (If you think you’re addicted to UPF, get help from a doctor or talk to someone about it.) You may want to adopt a diet where you eat some UPF but avoid whatever makes you feel bad or causes you to overeat. You may want to stop eating UPF altogether.

(Shortform note: Michael Pollan agrees that the best way to reclaim our health from our current industrialized diet is to stop eating UPF. His In Defense of Food provides additional detail about not only what we shouldn’t eat, but also what we should eat instead. Pollan says we should avoid food with more than five ingredients, food containing high-fructose corn syrup, packaged food with health claims on the label, and industrialized meats and produce. He says we should eat real food, which he defines as whole food or food containing ingredients your great-grandmother would recognize. He argues that we should eat mostly green plants, avoiding meat except in small amounts. Finally, we should eat a variety of fruits and vegetables for their diverse nutrients.)