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This week, I wrote about a new proposed definition for ultra-processed foods, which prompted excellent follow-up questions from readers. Many wanted to better understand why these products are considered harmful in the first place. As Gerald from Washington put it: “What is it about these substances that’s so bad? If it’s certain chemicals that are the problem, why not just ban those?”
To explore these questions, I spoke with Dalia Perelman, a research dietitian and health educator at Stanford University School of Medicine. She pointed out five key characteristics that help explain why ultra-processed foods are linked to worse health outcomes:
1. These foods tend to contain high levels of sugar, sodium and saturated fats. “The nutrient profile of these foods is usually not very good,” Perelman said. That means consuming too much of them poses long-term health risks. Excess sugar consumption contributes to weight gain and raises the risk of diabetes, while high sodium intake is linked to elevated blood pressure, a major risk factor for heart attacks and strokes. Diets high in saturated fat can increase harmful forms of cholesterol, which is also associated with cardiovascular disease.
2. They replace healthier foods. “It’s not just what you are eating,” Perelman explained, “but what you’re not eating when you are eating these foods.” For example, someone who chooses packaged macaroni and cheese is forgoing pasta made from garbanzo beans or lentils, or even a simple dish of semolina pasta with vegetables. Those latter options provide more fiber, vitamins, minerals and beneficial plant compounds such as phytochemicals.
3. Ultra-processed foods are engineered to be hyper-palatable. By that, Perelman means that manufacturers carefully design their products to make it easy for people to start consuming them and hard to stop. “They mix the precise amount of salt and fat in a potato chip, and they work on a lot of techniques to make the taste just right,” she said. “So when they say, ‘I bet you can’t eat just one,’ they really mean it.”
That’s because these foods override the body’s normal signals that it has had enough to eat. As a result, people end up eating larger quantities of sugar, salt and fat than they intend to.
4. They pack a lot of calories into small portions. Perelman explained that these products are often created with textures that make them easy to eat quickly. They may be very crunchy or soft, and people can consume a large amount without much chewing. “We get a lot more calories per bite,” she said.
Interestingly, this property can be useful in certain settings. Foods that are high in calories and easy to consume are sometimes used to help treat severe malnutrition in low-income countries. Nut butters, for instance, can provide concentrated energy for children who are not getting enough food. But in the United States, where 40 percent of adults have obesity, foods that deliver large numbers of calories with little effort serve no benefit and can instead contribute to excess weight gain.
5. Many contain industrial chemicals whose long-term health effects are not fully understood. One simple way to spot ultra-processed foods is to read the ingredient label. If it lists a long series of additives — such as emulsifiers, stabilizers, artificial colors or flavor enhancers — the product is likely ultra-processed.
Many of these compounds enter the food supply through a regulatory pathway known as “generally recognized as safe,” or GRAS. Ingredients in this category have typically been used in food for a long time, so experts at the Food and Drug Administration do not require the same level of review for them as they would for new additives.
But as Perelman argued, “We’re using the chemicals in higher doses and in different combinations that have never been studied.” It is also possible that certain compounds have different effects depending on the population consuming them. Some chemicals may pose little risk to adults while affecting children, whose bodies are still developing.
This is why Perelman supports the new definition proposed by researchers in a Nature Medicine paper, as I covered this week. Instead of trying to catalogue every ingredient or chemical that makes a food ultra-processed, their approach would identify what doesn’t count as ultra-processed. Any food that contains ingredients outside that category would, by definition, be considered ultra-processed.
The logic here is straightforward: Rather than trying to chase each chemical individually, it would be more practical to define the foods that clearly fit into a healthier category and encourage people to eat more of those.
Some readers questioned the practicality of this guidance. “People choose ultra-processed foods because they’re cheaper, more accessible, shelf-stable and quick to prepare,” wrote Chelsea from D.C. “It’s easy to say people should cook more from scratch, but a single mom working two jobs isn’t strolling through farmers markets and simmering lentils.”
Perelman acknowledged that many people rely on ultra-processed foods out of necessity. Indeed, that single mother, she said, suffers from “time poverty” — a chronic shortage of time that is closely tied to food insecurity. Making fresh, minimally processed foods as accessible and affordable as ultra-processed alternatives is a tall order.
But for those who do have flexibility, she suggests that people ask themselves a simple question about what they eat: Is this going to help me maintain my health? In the case of ultra-processed foods, the answer is often no.
The post Why are ultra-processed foods so bad? Answering your questions. appeared first on Washington Post.
