In just a few years, the term ultra-processed foods (AUT in French), or Ultra-Processed Foods (UPF), has moved from academic circles into the mainstream media.
In November 2025, the medical journal The Lancet devoted a series of three articles to the topic, co-authored by 43 international experts. Their conclusion was unequivocal: ultra-processed foods now represent a major public health issue, comparable to that of tobacco in previous decades.
What is an ultra-processed food?
The work published in The Lancet draws on the NOVA classification, which categorises foods not by their nutrient content — fat, sugar or salt — but by their degree of industrial processing.
An ultra-processed food is characterised by:
a complex industrial formulation,
the use of substances rarely found in home cooking, such as modified starches, glucose-fructose syrups, protein isolates and hydrogenated oils,
the frequent presence of so-called "cosmetic" additives: colourings, flavourings, emulsifiers, sweeteners and flavour enhancers.
Ultra-processed foods are not limited to fast food. They include:
breakfast cereals,
commercially produced biscuits and pastries,
protein or "health" bars,
soft drinks and diet drinks,
ready meals, frozen pizzas and nuggets,
some highly processed plant-based substitutes,
many products intended for children.
In France, these products account for around a third of calorie intake, and up to 60% in some countries, such as the United States.
What do scientific studies show?
The authors in The Lancet synthesised cohort studies and meta-analyses involving several hundred thousand people. The results are particularly robust.
More than 100 longitudinal studies show a clear association between high consumption of ultra-processed foods and poorer health.
More than 30 conditions are associated with high UPF consumption, including:
obesity and overweight,
type 2 diabetes,
cardiovascular disease,
certain cancers,
digestive disorders,
sleep disorders,
mental health conditions,
increased all-cause mortality.
Some key figures
Around 15% higher mortality risk among the highest consumers,
17% higher risk of cardiovascular disease,
12% higher risk of type 2 diabetes for every 10% increase in UPFs in the diet.
These effects cannot be explained solely by excess calorie intake. At equivalent energy intakes, a diet rich in ultra-processed foods damages health more rapidly than one based on minimally processed foods.
Why are ultra-processed foods a problem?
The medical journal The Lancet highlights a crucial point: the problem goes far beyond the trio of fat, sugar and salt. Several mechanisms, which probably act together, are involved.
1. Changes to food structure and the food matrix
Ultra-processed foods are often soft, easy to swallow and require little chewing.
Satiety is delayed, encouraging people to eat faster and in larger quantities.
2. Additives and contaminants
Certain emulsifiers, sweeteners, flavourings or contaminants from packaging may disrupt:
the gut microbiota,
the intestinal barrier,
hormonal and metabolic regulation.
3. Hyper-palatability and design that encourages overconsumption
UPFs are formulated to maximise sensory pleasure and the brain’s reward response through a combination of fat, sugar and salt, encouraging automatic and repeated consumption.
4. A constant presence in everyday life
Snacks, grazing, on-the-go products, sugary or diet drinks: ultra-processed foods now feature throughout the day and are gradually replacing simple foods such as fruit, nuts and home-cooked meals.
These products are therefore low in satiety, highly energy-dense and backed by powerful marketing, encouraging excessive consumption.
An individual problem… but above all a systemic one
Reducing the issue to individual responsibility is not enough. The growth of ultra-processed foods is primarily the result of an economic and industrial system :
concentration within the food industry,
cost optimisation through ultra-processed formulations,
extensive marketing, particularly aimed at children,
a strong presence in schools, hospitals, vending machines and delivery platforms,
public health policies focused solely on nutrients, overlooking the degree of processing.
The authors compare the current situation to the early stages of tobacco control: scientific evidence is mounting, but policy responses remain limited.
What does this mean in practice?
A key concept highlighted by recent studies is the metabolic memory of adipose tissue.
Even after significant weight loss, adipose tissue does not fully return to its initial state.
Researchers observe lasting changes in:
gene expression,
chromatin organisation,
epigenetic markers, such as DNA methylation.
This biological memory could explain:
the tendency to regain weight after dieting,
the difficulty of maintaining weight loss in the long term,
persistent metabolic disturbances, including inflammation and insulin resistance.
These findings do not call into question the effectiveness of lifestyle changes or treatments, but help us understand why the body sometimes resists weight loss and why some patients need more intensive, sustained support.
The brain: orchestrating appetite and satiety
The aim is not to eliminate ultra-processed foods entirely, which is often unrealistic, but to significantly reduce their place in the diet, particularly when they feature at several points throughout the day.
At a societal level:
Explicitly include the concept of ultra-processing in dietary recommendations.
Regulate advertising and marketing, particularly when aimed at children.
Improve the affordability of fresh and minimally processed foods.
Regulate the power of major food companies and conflicts of interest.
Train healthcare professionals and inform the public.
At an individual level:
Prioritise simple foods: fruit, vegetables, pulses, whole grains, eggs, plain dairy products, and minimally processed meat and fish.
Cook more often: it is frequently healthier and more economical than ready meals.
Be wary of products with a misleading health image: protein products, fitness drinks and ultra-processed foods with no added sugar.
Gradually reduce the UPFs consumed most often: soft drinks, biscuits, snacks and industrially produced pastries.
What is the message for healthcare professionals?
Several key points emerge for healthcare professionals:
Include the degree of processing in nutritional advice, looking beyond nutrients alone.
Understand that UPF consumption is not simply a matter of individual willpower.
Bear in mind that certain genetic profiles may be more vulnerable to this diet, with a greater impact on inflammation, metabolism and cardiometabolic risk.
Conclusion: a major, modifiable determinant of health
The evidence brought together by The Lancet confirms that ultra-processed foods are a major, modifiable determinant of health, going well beyond simply too much fat, sugar or salt.
Their impact involves both biological mechanisms — the microbiota, satiety and hormonal regulation — and a food environment designed to encourage consumption.
The response must be twofold:
ambitious public policies,
and support for individuals to move towards a diet centred on minimally processed foods and simple meals cooked from basic ingredients.
Scientific source: series The Lancet on ultra-processed foods.