What Ultraprocessed Foods Are Doing to Your Body

The science is no longer subtle. Decades of research now link ultraprocessed foods to liver disease, cancer, heart disease, brain changes, and early death — and the mechanisms are becoming clear.

"Ultraprocessed foods target the brain reward circuits that keep us coming back for more. They trigger overeating. They deprive us of any sense of fullness." - David Kessler, MD, Former Commissioner of the U.S. Food and Drug Administration

What Exactly Is an Ultraprocessed Food?

Not all processed food is the same. Cutting a vegetable is processing. Pasteurizing milk is

processing. Ultraprocessed foods (UPFs) are something categorically different: industrially manufactured products formulated with ingredients that have no equivalent in a home kitchen — synthetic emulsifiers, artificial flavor enhancers, colorants, preservatives, thickeners, and sweeteners engineered to maximize palatability, shelf life, and the impulse

to keep eating.

The NOVA classification system, developed by researchers at the University of São Paulo

and now used globally, defines UPFs as Group 4 — products that go beyond adding salt,

sugar, or fat, and instead use industrial processes and substances that alter the

fundamental character of food. Common examples: packaged snacks, sodas, instant

noodles, sweetened breakfast cereals, fast food, processed deli meats, frozen pizzas,

flavored yogurts, and most packaged bread.

In the United States, UPFs now account for approximately 57% of the calories adults

consume and 67% of the calories in children's diets. That number has risen steadily for

decades — and so has the disease burden that research now directly associates with it.

The Brain: Engineered to Override Your Willpower

David Kessler, MD — the former FDA Commissioner who led the agency's effort to

regulate tobacco — spent years investigating what the food industry had learned about

engineering overconsumption. His conclusion was unambiguous: ultraprocessed foods are

deliberately designed to hijack the brain's reward system in ways that override normal

appetite regulation.

The mechanism involves the brain's mesolimbic dopamine pathway — the same reward

circuitry involved in drug addiction. When sugar and fat are combined in the precise ratios

found in UPFs — ratios that almost never appear together in nature — the brain registers

an outsized reward signal. Research published in Cell Metabolism in 2018 found that

combinations of fat and carbohydrate produced supra-additive effects on brain reward

circuits, meaning the combination is more stimulating than either macronutrient alone.

A 2025 review in ScienceDirect confirmed that chronic overconsumption of UPFs alters

dopaminergic tone, disrupts prefrontal cortex control over impulse behavior, and activates

stress pathways — creating a neurobiological loop that reinforces continued eating even in

the absence of hunger. Researchers using the Yale Food Addiction Scale have found that

approximately 15 to 20% of adults meet the clinical criteria for food addiction based on

DSM-5 substance use disorder criteria, including diminished control over intake, cravings,

and continued use despite negative consequences.

An important nuance: a 2024 PET imaging study found that the dopamine response to

UPFs is highly variable between individuals and not simply explained by body weight

alone. The addiction model is still being refined. What is consistent across the research is

that UPFs disrupt normal satiety signaling — the gut hormones and neural feedback that

tell you when you have had enough — and that this disruption drives overconsumption

independently of conscious decision-making. This is exactly what Kessler described: foods

designed to deprive you of any sense of fullness.

The Liver: The Most Damaging Relationship in Modern Nutrition

Of all the organ systems affected by UPF consumption, the liver has some of the strongest and most consistent evidence. The research has now reached the scale of meta-analysis — pooling data across hundreds of thousands of participants — and the findings are striking.

A 2025 meta-analysis published in the Journal of Food Science — analyzing 17 studies

involving over 1,092,950 participants — found that UPF consumption significantly increased the risk of adverse liver outcomes overall (58% higher odds). Breaking it down by condition:

Liver condition	Increased risk with high UPF consumption	Source
Non-alcoholic fatty liver disease (NAFLD)	72% higher odds (OR = 1.72)	Journal of Food Science meta-analysis, 2025 - 17 studies, 1,092,950 participants
Liver fibrosis	31% higher odds (OR = 1.31)	Journal of Food Science meta-analysis, 2025
Liver cancer (hepatocellular carcinoma)	35% higher odds (OR = 1.35)	Journal of Food Science meta-analysis, 2025
NAFLD (dose-response)	6% higher risk per 10% increase in UPF intake	Frontiers in Nutrition systematic review, 2025 — 10 studies, 513,440 participants
NASH (non-alcoholic steatohepatitis)	89% higher odds among NAFLD patients	Ivancovsky-Wajcman et al., PubMed — cross-sectional with FibroMax assessment

The liver mechanisms are well characterized. When UPFs are consumed regularly,

fructose from high-fructose corn syrup overwhelms the liver's metabolic capacity, triggering

de novo lipogenesis — the conversion of sugar into fat stored directly in liver cells. This is

the starting point for NAFLD. Simultaneously, synthetic emulsifiers and food additives in

UPFs damage the gut's mucosal barrier, allowing lipopolysaccharide (LPS) from gut

bacteria to leak into the portal circulation and travel directly to the liver, where it activates

Kupffer cells and amplifies hepatic inflammation. Over time — without any obvious

symptoms — this progression moves from fatty liver to NASH to fibrosis to cirrhosis.

A 2025 study in Frontiers in Nutrition using NHANES data from 4,992 U.S. adults found

that those in the highest quartile of UPF consumption had significantly greater liver

steatosis scores compared to the lowest quartile — even after controlling for BMI, physical

activity, alcohol use, and other confounders. The liver damage from UPFs is not simply

explained by the weight gain they cause. The foods themselves — and the additives within

them — are independently harmful to liver tissue.

Key source	Guo et al. Ultra-Processed Food Intake and Risk of Adverse Liver Outcomes: A Meta-Analysis. Journal of Food Science. 2025. DOI: 10.1111/1750-3841.70303 — 17 studies, 1,092,950 participants
Key source	Zhang J, Shu L, Chen X. Ultra-processed foods and NAFLD: updated systematic review and dose-response meta-analysis. Frontiers in Nutrition. 2025. DOI: 10.3389/fnut.2025.1631975
Key source	Song J et al. Association of ultra-processed foods consumption with increased liver steatosis in U.S. adults. Frontiers in Nutrition. 2025. DOI: 10.3389/fnut.2025.1536989

The Rest of the Body: 32 Health Parameters. One Food Category.

In 2024, a landmark umbrella review published in The BMJ synthesized 45 meta-analyses

covering nearly 10 million study participants. The conclusion was categorical: high UPF

consumption was directly associated with 32 different adverse health outcomes spanning

mortality, cancer, and mental, respiratory, cardiovascular, gastrointestinal, and metabolic

health. The evidence for several outcomes was rated "convincing" — the highest level of

certainty in epidemiological research.

Body system	Finding	Risk increase
Heart & cardiovascular	Death from cardiovascular disease	50% higher risk
Heart & cardiovascular	Death from heart disease specifically	66% higher risk
Metabolic	Obesity	55% higher risk
Metabolic	Type 2 diabetes	40% higher risk
Mental health	Anxiety	48% higher risk
Mental health	Depression	20% higher risk
Sleep	Sleep disorders	41% higher risk
Cancer	Colorectal cancer (men)	29% higher risk
All-cause	Early death from any cause	21% higher risk

*Source: Lane et al. Ultra-processed food exposure and adverse health outcomes: umbrella review of 45 meta-analyses, ~10 million participants. BMJ. 2024;384:e077310.

The Gut: Where the Damage Often Begins

A 2024 review in Nature Reviews Gastroenterology & Hepatology confirmed that UPFs and

their additives are directly associated with increased risk of inflammatory bowel disease,

colorectal cancer, and irritable bowel syndrome. The mechanisms center on how food additives alter the gut microbiome and damage the intestinal barrier.

Research shows that high UPF consumption is associated with higher levels of harmful

bacteria including Granulicatella and Bacteroidaceae, and lower levels of beneficial

short-chain fatty acid producers like Roseburia and Lachnospira. Emulsifiers like

carboxymethylcellulose and polysorbate-80 prevent the proliferation of beneficial bacteria,

increase gut permeability, and allow bacterial products to enter the bloodstream —

triggering the systemic inflammation that drives damage in the liver, heart, brain, and

beyond.

The Brain (Again): Memory, Cognition, and Dementia

A 2024 study covered by ScienceDaily found that people who eat more ultraprocessed

foods may have a higher risk of memory and thinking problems and stroke than those who

eat fewer. Higher UPF consumption was associated with structural differences in the brain

itself — changes that could form part of a feedback loop promoting continued overeating.

The connection between UPFs and dementia risk is an active and rapidly developing area

of research.

It Is Not Just What Is Added. It Is What Is Missing.

Stanford research dietitian Dalia Perelman put it precisely: "It's not just about what's added

to these foods; it's what's missing." UPFs are stripped of the fiber, polyphenols,

magnesium, and micronutrients that whole foods provide — the very compounds that

actively support anti-inflammatory pathways, feed beneficial gut bacteria, regulate blood

sugar, and protect liver cells. The damage is therefore dual: synthetic additives trigger

harm while the removal of whole-food nutrients strips the body of its natural repair

mechanisms.

Multiple studies have confirmed that the harmful associations of UPFs are not fully

explained by their sugar, salt, or fat content alone. A 2025 prospective cohort study of

39,544 Australian adults published in the European Journal of Preventive Cardiology found

that the association between UPF consumption and cardiovascular mortality remained

robust after controlling for overall diet quality and nutrient intake — suggesting that specific

characteristics of ultraprocessed foods, beyond their macronutrient composition, are

independently driving the harm.

The Root Cause Perspective

When clients come to root cause health coaching with unexplained fatigue, liver enzyme

abnormalities, weight they cannot shift, brain fog, digestive problems, or mood instability —

the first question is always: what is driving the underlying inflammation? UPFs are, for a

significant number of people, a primary answer. Not the only answer. But a foundational

one.

Former FDA Commissioner David Kessler was not speaking loosely when he said these

foods target reward circuits, trigger overeating, and deprive people of any sense of

fullness. That is a precise description of what the neuroscience and behavioral research

have found. And it matters — because it means the difficulty most people experience in

reducing UPF consumption is not a character flaw. It is a neurobiological response to foods

that were engineered to produce exactly that response.

The research is unambiguous about what ultraprocessed foods do to the liver, the gut, the

brain, and the cardiovascular system. What it also makes clear is that every incremental

reduction matters. A 2025 dose-response meta-analysis found that every 10% decrease in

UPF intake was associated with a 6% reduction in NAFLD risk.

The body is responsive. The damage is not inevitable. And for most people, the most powerful single dietary change they can make is simply to eat food that was actually made from food.

Need support?

Have questions about what ultraprocessed foods are doing to your body? Looking for nutritional guidance and support? Book a Discovery Call with Cami. Call or text (214) 558-0996 or click below to check the calendar and book online.

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*This article is for educational purposes only and does not constitute medical advice. Consult a qualified healthcare provider before making changes to your diet or health regimen.