Ultra-processed foods (UPFs) make up more than half of what most people eat - but what actually counts as ultra-processed, and why does it matter for your gut and long-term health?

 

What Are Ultra-Processed Foods?

Ultra-processed foods are industrial formulations made mostly from refined ingredients, additives, and preservatives, often with little or no whole food left. Common examples include soft drinks, flavoured yoghurts, ready meals, protein bars, breakfast cereals, and processed meats.

If a label lists ingredients you wouldn’t normally use in your own kitchen - emulsifiers, colourings, flavourings, or stabilisers - it’s almost certainly an ultra-processed food.

The NOVA classification system groups foods by the degree of processing, from unprocessed (Group 1) to ultra-processed (Group 4). UPFs sit at the far end of that spectrum.

 

A Short History of Ultra-Processing

Food processing began as a way to preserve and stabilise nutrition, but the industrial revolution transformed it into mass production. Artificial sweeteners like saccharin appeared in 1879, and by the early 1900s hydrogenation made cheap, shelf-stable oils possible - the birth of trans fats.

Though trans fats were eventually banned for their role in heart disease, they marked the start of large-scale food industrialisation and a diet increasingly built from refined, additive-rich ingredients.

 

Why Are Ultra-Processed Foods a Problem?

1. Nutrient Dilution

UPFs are typically energy-dense but nutrient-poor; high in calories, refined carbohydrates, added sugars, and industrial fats, yet low in fibre, vitamins, minerals, and antioxidants. Even when calorie needs are met, the lack of micronutrients can affect metabolism, immunity, and cellular repair.

2. Additives and the Gut Microbiome

Many UPFs contain emulsifiers, stabilisers, and artificial sweeteners that aren’t found in home-cooked meals. Emerging research shows these additives can alter the gut microbiome, weaken the intestinal barrier, and promote low-grade inflammation. Reduced fibre intake further limits production of short-chain fatty acids (SCFAs) such as butyrate, essential for gut and immune health.

3. Appetite and Energy Balance

Because UPFs are soft, palatable, and quickly digested, they’re easier to over-consume. In one controlled study, people eating a diet high in UPFs consumed roughly 500 extra calories per day and gained fat mass, even when meals were matched for macronutrients.

4. Metabolic and Hormonal Effects

Frequent UPF consumption is associated with insulin resistance, inflammation, and higher risk of type 2 diabetes and cardiovascular disease. These effects appear to stem from rapid blood-sugar spikes, reduced satiety, and changes to the gut-brain axis that disrupt appetite and hormone balance.

 

Are All Processed Foods Bad for You?

No. Processing exists on a spectrum. Cooking, freezing, fermenting, and pasteurising are beneficial forms that improve safety and nutrition.

The goal isn’t to eliminate convenience foods but to recognise when processing becomes ultra-processing - when structure, fibre, and nutrient density are stripped away in favour of shelf life and hyper-palatability.

 

What Does Research Say About Health Risks?

Large population studies link high UPF intake to:

• Obesity and weight gain
• Type 2 diabetes and cardiovascular disease
• Gut dysbiosis and “leaky gut”
• Depression and anxiety
• Certain cancers, including colorectal cancer

A 2023 umbrella review covering nearly 10 million people found that those who ate the most UPFs had significantly higher risk of heart disease, metabolic syndrome, and all-cause mortality.

 

How Do Ultra-Processed Foods Affect the Gut?

When UPFs displace whole foods, the microbiome loses access to diverse fibres and polyphenols that feed beneficial bacteria. Additives such as emulsifiers and artificial sweeteners may increase intestinal permeability, allowing inflammatory molecules to enter the bloodstream. Over time this imbalance - called gut dysbiosis - can influence digestion, immunity, mood, and even sleep.

 

Can Ultra-Processed Foods Disrupt Hormones?

Yes. Refined sugars and fats can trigger rapid glucose and insulin spikes, while low nutrient density affects thyroid and sex-hormone balance. Packaging chemicals such as BPA and phthalates may also act as endocrine disruptors, further disturbing hormonal rhythms. These mechanisms help explain why diets high in UPFs correlate with poor sleep, mood changes, and metabolic fatigue.

 

How to Reduce Ultra-Processed Foods

You don’t need to cut everything out - aim for awareness and small, consistent swaps.

Practical tips:

• Choose foods close to their natural structure — whole grains, legumes, fruits, vegetables, nuts, and seeds.
• Cook at home more often; even simple meals reduce additive exposure.
• Read ingredient lists and favour short, recognisable ones.
• Keep an 80 / 20 balance: mostly whole foods, some flexibility for convenience.
• Remember Michael Pollan’s rule: “Eat food. Not too much. Mostly plants.”

 

What Role Does Gut Testing Play?

If you’re reducing ultra-processed foods, it helps to see how your gut microbiome responds.

• StrideBiome measures the balance and diversity of your gut bacteria and identifies how your diet influences key compounds like butyrate.
• StrideOne connects gut, blood, and DNA data to show how food choices affect inflammation, energy, and hormones.
• GS-01 Gut Support is a scientifically developed synbiotic to help restore microbial balance and support the same pathways affected by UPFs.

By combining testing with daily support, Stride makes gut health measurable, personal, and actionable.

 

The Bottom Line

Ultra-processed foods aren’t just empty calories - they reshape your metabolism, hormones, and gut health from within. Understanding what they are, why they matter, and how your own biology responds is the first step toward balance.

Every swap toward real, fibre-rich, minimally processed food strengthens your gut, your energy, and your long-term health.