UPFs and Hyper-Palatability Under the Microscope

Ultra-processed foods (UPFs) have become a lightning rod in nutrition science and consumer discourse, with critics arguing that they are deliberately engineered to override satiety signals and fuel overconsumption. In an IFT FIRST Hot Topics Studio session titled “Are Ultra-Processed Foods Engineered to Be Irresistible?”, Richard Mattes, distinguished professor and director of the Ingestive Behavior Research Center at Purdue University, joined moderator Lisa Sanders, owner and principal scientist at Cornerstone Nutrition, to unpack the evidence.

No Agreed-Upon Definition

“You would think this would be a simple question with a simple answer … but it’s anything but that,” Mattes said. Nova is the most widely cited classification system, but others exist, including those from the International Agency for Research on Cancer and the University of North Carolina. “Bottom line is there isn’t a good definition, and that was reinforced by the Dietary Guidelines Advisory Committee … their conclusion was because of a lack of definition, it is impossible to draw conclusions about the link to health outcomes.”

Evidence Gaps

When Sanders asked whether there was sufficient evidence to incorporate UPFs into dietary guidance, Mattes stressed the need for three tiers of science: epidemiology, randomized controlled trials, and mechanisms.

“There is an abundance of epidemiologic evidence linking consumption of UPFs with a whole array of health outcomes … diabetes, cardiovascular disease, obesity, you name it,” he said. “However … those associations are very, very small. This is not the gorilla in the room.”

He noted that UPF intake has remained stable even as obesity rates have climbed and that vegan and vegetarian diets—often considered healthful—derive about 40% of energy from UPFs. On clinical studies, he cited just one two-week trial with 20 people that showed a short-term rise in energy intake but suggested the effect would have disappeared in another week. His own group reviewed 16 proposed mechanisms linking UPFs to disease but found none with strong evidence.

Palatability vs. Hyper-Palatability

Sanders pressed Mattes on the notion that foods are engineered to be irresistible. “There is no universal definition of hyper-palatable. ‘Hyper’ is clearly a sensationalist term to raise fear and concern. There is no scientific definition of hyper, let alone hyper-palatable,” he said.

For Mattes, palatability is subjective: “Palatability is a characteristic of a person. It’s not a property of a food.” He pointed to coffee preferences, cultural differences, and age-related shifts in taste as evidence that appeal resides in the consumer, not the product.

Risks of Policy Without Science

Audience questions pushed the discussion further. On food addiction, Mattes said: “It’s not possible to have a true addiction to something that you are required to live [on]—energy and nutrients and so on.”

He warned that removing UPFs without clear evidence could have unintended effects. “Eliminating foods that have preservatives in them will lead to an increase in foodborne illness. … Often UPFs are less expensive for people who are food insecure. They actually derive a lot of nutrients of short supply from UPFs. There’s a very real possibility that eliminating these foods will lead to nutritional problems rather than solutions.”

Julie Hess’s review, he added, showed that foods classified as UPFs can still align with dietary guidelines for healthy diets.

A Call for Caution

Mattes closed by acknowledging the public health drive to act but urged patience: “Future science, if we get a definition and we do good science and it shows there are a subgroup of foods that are really causally related to poor diet, I’ll be as supportive of that as anybody else. But I don’t think the science is there and the potential dangers are too great, in my opinion, to go forward.”ft