Why ultra-processed foods are bad for you

Ultra-processed foods don't cause weight gain simply because they are high in calories. The mechanism is more insidious: they are engineered to be hyper-palatable and actively interfere with the body's natural satiety signals.

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  High energy density

  UPFs contain on average 2.15 kcal per gram — almost double that of fresh foods. The same volume of food delivers far more calories, without the corresponding feeling of fullness.

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  Excessive stimulation of pleasure centres

  The industrial combination of sugar, salt, fat, and flavourings activates the dopaminergic system in a manner similar to addictive substances. The result: eating continues even in the absence of real hunger.

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  Reduction of peptide YY

  UPFs lower levels of peptide YY, the gut hormone that signals fullness to the brain. People who eat a lot of ultra-processed foods receive fewer "stop" signals after meals.

Frequent consumption of ultra-processed foods is associated with an increase in inflammatory immune responses in the body — an effect that goes well beyond the simple nutritional profile of the product.

Some substances commonly found in UPFs — emulsifiers, thickeners, and microparticles such as titanium dioxide (E171) — can alter the gut microbiota and increase the permeability of the intestinal mucosa. This phenomenon, known as leaky gut, allows pathogenic bacteria and harmful substances to enter the bloodstream, triggering chronic systemic inflammation.

Chronic immune dysfunctions induced by UPFs are associated with a higher risk of developing autoimmune diseases:

The industrial ultra-processing method strips foods of dietary fibre and bioactive plant compounds (polyphenols, antioxidants) needed to nourish the "good" bacteria in the gut. In their place, added sugars, salt, artificial sweeteners, and additives abound, promoting an imbalance in the microbiota — known as dysbiosis.

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  Dysbiosis: less bacterial diversity, more risks

  An impoverished microbiota — with fewer beneficial bacterial species — is associated with insulin resistance, chronic inflammation, and greater vulnerability to infections and metabolic diseases. UPFs actively reduce this diversity.

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  Weakening of the protective mucous layer

  The abundance of emulsifiers and artificial sweeteners weakens the mucus layer lining the intestine, reducing the physical barrier between gut bacteria and the colon wall.

Observational studies show that people who consume large quantities of UPFs more frequently suffer from:

What makes UPFs particularly concerning is not a single negative effect, but the convergence of multiple mechanisms that reinforce one another.

In summary, UPFs act as a systemic risk factor that simultaneously promotes insulin resistance, oxidative stress, and low-grade chronic inflammation — three conditions that underlie almost all the most prevalent chronic non-communicable diseases in the Western world.

The scientific evidence is solid, but the practical message is not "eliminate everything". It is reduce the share of UPFs in your daily diet and replace them with simple alternatives, where available and accessible.

1. 1
   Identify your habitual UPFs

   Sweetened breakfast cereals, packaged snacks, sliced bread with additives, ready meals, flavoured drinks: these are the products that, consumed daily, make the difference. Not ice cream once a month.

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   Substitute one at a time

   No revolution needed. Rolled oats instead of sweet cereals. Plain Greek yogurt instead of flavoured yogurt with thickeners. Artisan bread instead of sliced bread with preservatives. Each substitution reduces the cumulative burden.

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   Increase fibre — it's the priority

   Legumes, vegetables, whole-grain cereals, whole fruit: fibre feeds the beneficial bacteria in the microbiota and directly counters many of the negative effects of UPFs. It doesn't require "eliminating" anything — only adding.

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   Use the app to identify hidden UPFs

   Many products that appear healthy ("protein" bars, "0%" yogurt, "fruit" juices) are actually NOVA 4. Scanning the barcode with E-Codes Reader instantly shows the NOVA classification and the additives present.

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   Don't aim for perfection

   The goal is not a "pure" diet. It's that the majority of what you eat each week is real food — and that ultra-processed foods remain the exception, not the foundation. Even a 20–30% improvement in diet quality produces measurable health effects in the medium term.