Ultra-processed foods are linked to obesity, type 2 diabetes and cardiovascular disease – but what are they actually doing to the body? 

Ultra-processed foods now make up a substantial part of what many people eat every day. 

“Ultra-processed foods now make up a substantial part of what many people eat every day,” says Benjamin A. H. Jensen, Associate Professor at the University of Copenhagen. “We are increasingly realising that they may harm health in ways that go beyond calories, fat and sugar.” 

At the same time, the discussion around ultra-processed foods is accelerating. 

“The public debate is moving very fast, sometimes faster than the science,” he says. “We urgently need nuanced, data-driven discussions that can guide patients, clinicians and policy.” 

If the debate is moving faster than the science, the question becomes what the science is actually able to explain. 

Why Ultra-processed Foods are Difficult to Define 

“One major complexity is definition,” Jensen explains. “There is no universal agreement on what ‘ultra processed’ actually means, and different classification systems do not always place the same foods in the same category.” 

This makes it difficult to align findings across studies and draw consistent conclusions. 

“Disentangling processing from nutrient composition, additives, food structure and eating behaviour is complex,” he says. “All of these factors may contribute.” 

“Epidemiologists, clinicians, basic scientists, food technologists and regulators often look at the same products through very different lenses,” Jensen adds.

What Happens in the Body 

“Think of your gut microbiome as a software that is constantly being updated and reprogrammed by your diet,” says Benoit Chassaing, Research Director and Head of the Microbiome-Host Interactions unit at Institut Pasteur. “Ultra-processed foods are not just feeding us. They are programming our gut bacteria in ways we never expected.” 

“After two decades of intensive research, we have moved beyond simply describing the microbiome to actually understanding the mechanisms behind it,” he says. 

“Beyond the lack of fibre, which starves beneficial bacteria, we are closely examining additives once considered harmless, including emulsifiers, artificial sweeteners, food colourants and even nanoparticles,” Chassaing explains. “These ingredients are proving to be anything but inert.” 

His research examines how genetic and environmental factors can disrupt the intestinal microbiota and contribute to intestinal inflammation, and how diet shapes microbial composition and function in both health and disease. 

From Understanding to Application 

“We can now characterize how dietary factors and environmental stressors shape these microbial communities,” Chassaing says. “This understanding gives us a concrete biological readout of why certain foods promote health while others drive disease.” 

“We are at an incredibly exciting inflection point where decades of basic research are finally translating into clinical applications,” he says. 

Beyond “Good” and “Bad” 

“Our ambition was to build the programme for the upcoming DDEA event Navigating the Complexities of Ultra-processed Foods so that it moves beyond simple ‘UPFs are good or bad’ narratives,” says Jensen, who is part of the organising committee. “Instead, we ask mechanistic questions.” 

These mechanistic questions include how ultra-processed foods affect gut barrier integrity, microbiome composition and low-grade inflammation, and how this may translate into cardiometabolic risk over time. 

Where These Questions Come Together 

“Epidemiologists, clinicians, basic scientists, food technologists and regulators often look at the same products through very different lenses,” Jensen says. 

Bringing these perspectives together is one of the central challenges in the field. 

This is also the starting point for the DDEA event Navigating the Complexities of Ultra-processed Foods, where researchers, clinicians and industry professionals meet to examine these questions across disciplines. 

Across four sessions, participants will explore key questions such as how ultra-processed foods are defined, why foods are processed, and what current research suggests about health effects and underlying mechanisms. 

“I hope participants leave with a more critical and more nuanced understanding of ultra-processed foods,” Jensen says. “Aware of the strength of the evidence, but also of the uncertainties and gaps.” 

“If we can collectively refine the questions we ask in the next generation of studies,” he adds, “the symposium will have done its job.” 

Ultra-processed foods are widely discussed, but the mechanisms behind their effects are only beginning to be understood.

Event Details: Navigating the Complexities of Ultra-processed Foods 

Date: 4 May 2026, 10:15–17:00 
Location: Arla Foods Head Office, Sønderhøj 14, 8260 Viby J, Denmark 
Registration deadline: 12 April 2026, 23:59 

Explore the programme and see how these questions will be addressed: 
https://ddeacademy.dk/events/networking/navigating-the-complexities-of-ultra-processed-foods/