Ultra-processed foods often taste great and fill you up fast, but they pack a lot of added sugar, salt, and saturated fat while offering little protein, fiber, or micronutrients. Manufacturers also routinely add mixes of food additives to improve flavor, texture, color, and shelf life. Think sodas, packaged cookies and cakes, sugary cereals, mass-produced bread, ready meals, flavored yogurts, processed meats, and fast food.
Occasional processed treats fit into an overall balanced diet — life would be less enjoyable without bacon, cookies, or the occasional burger. Processed foods can also be handy when time or money are tight. The problem starts when “sometimes” turns into “every day.”
Regularly eating large amounts of ultra-processed food has been linked to numerous diseases. To help you make smarter choices, here are the main culprits — ingredients experts recommend limiting or avoiding first.
1. Artificial food dyes tied to behavioral effects in children
Artificial dyes are synthetic colors added to foods to boost or restore appearance. In the EU and the UK they appear as E-numbers; in the US they show up as FD&C dyes approved by the FDA.
The biggest concerns focus on tartrazine (E102 / FD&C Yellow 5), Sunset Yellow (E110 / FD&C Yellow 6), and Allura Red (E129 / FD&C Red 40). Manufacturers add these to candies, sodas, desserts, and breakfast cereals, and also to sauces, cheeses, and meat substitutes to give them a more “meaty” hue.
Many studies link these dyes to behavioral effects in children — increased hyperactivity, attention problems, and mood swings — and in some kids they can worsen symptoms of ADHD. In the EU and UK product labels that contain these dyes must carry the warning: “may have an adverse effect on activity and attention in children.” Consumer pressure has pushed many British brands to phase these dyes out. They remain widely used in the US, though some schools and localities are starting to restrict them.
2. Nitrates and nitrites in processed meats linked to higher cancer risk
Nitrate and nitrite preservatives are commonly added to processed meats — bacon, sausages, hams, and deli meats — to extend shelf life, preserve a pink color, and create that characteristic flavor. Nitrate itself isn’t necessarily harmful, but bacteria during processing or in the mouth can convert it into nitrite.
Watch for sodium nitrite (E250), sodium nitrate (E251), potassium nitrite (E249), and potassium nitrate (E252). In the acidic environment of the stomach, nitrites can form nitrosamines — compounds linked to an increased risk of colorectal cancer.
In 2015 the International Agency for Research on Cancer (IARC) at WHO classified processed meat as carcinogenic. In the UK, scientists have already urged putting cancer-risk warnings on bacon and ham packaging.
In January 2026 two large French studies linked higher intakes of nitrates, nitrites, and other preservatives to increased risks of cancer and type 2 diabetes. The data come from NutriNet-Santé, a large French cohort that tracks diet and health in more than 100,000 adults.
In the cancer study, greater intake of sodium nitrite was associated with a higher prostate cancer risk. By age 60 the absolute risk — the share of people who develop the disease — rose from about 3.4% in the lower-intake group to about 4.2% in the higher-intake group. A similar pattern appeared for breast cancer: potassium nitrate intake was associated with an increase in absolute risk from roughly 4.8% to 5.9% by age 60.
Those individual increases look modest for one person, but even small rises in absolute risk across a population can mean a substantial number of extra cases.
The good news: these studies don’t call for completely cutting out ham, bacon, or sausages. Risk increases with higher and more frequent consumption of nitrite- and nitrate-containing products. People who ate them less often still ate these foods — just not regularly. So an occasional bacon sandwich isn’t a disaster.
3. Emulsifiers that can disrupt your gut microbiome
Emulsifiers are among the most common additives in processed foods. They help blend and stabilize ingredients that don’t normally mix, like oil and water, giving products a smooth texture and longer shelf life.
Among the long list of emulsifiers, carboxymethylcellulose and polysorbate-80 come up most often as concerning. You’ll find them in breads and baked goods, ready meals, frozen pizzas, burgers and nuggets, sauces, pastes, and sweets.
The main worry centers on the impact on the gut microbiome — the trillions of microbes living in the digestive tract that support health. Several studies show that carboxymethylcellulose and polysorbate-80 can disturb that delicate balance.
In one experiment both emulsifiers caused long-lasting changes in gut microbes and shifted the microbiome toward a more inflammation-prone state. Chronic inflammation links to higher risks of inflammatory bowel disease (IBD) and metabolic problems, which in turn raise the risk of type 2 diabetes and cardiovascular disease.
Another study tied those microbiome changes to significant weight gain and suggested that widespread use of these emulsifiers could be contributing to rising obesity and chronic inflammatory conditions.
That said, regulators and experts currently consider emulsifiers safe, and they often appear in foods that also provide needed nutrients. Also remember that foods from the “healthy” aisle can contain emulsifiers too: “multigrain” bread or “reduced-fat” yogurts may look healthy but can include several emulsifiers — so read ingredient lists.
4. Interesterified palm fats used to improve texture and shelf life
Interesterified palm oil is used in margarines and spreads, cookies, cakes, baked goods, chocolate, and some dairy alternatives. Interesterification chemically restructures fat molecules, which changes how the fat behaves: spreads become easier to spread, pastries get flakier, and products last longer.
Interesterified fats appeared as an alternative to industrial trans fats, which are clearly harmful to the heart. While interesterified fats are considered less dangerous than trans fats, long-term health effects aren’t fully settled.
The main concern is that the interesterification process can make saturated fats easier to absorb and metabolize. Studies of commercial palm-oil blends show higher blood lipid spikes after eating those fats compared with non-interesterified fats. Those lipid spikes add strain to the heart and blood vessels and are associated over time with increased cardiovascular risk.
Another problem is that interesterified fats are hard to spot on labels: manufacturers don’t always have to specify that a fat is interesterified, so an ingredient list might simply say “palm oil.” People can’t tell how much they’re eating, and scientists don’t yet have precise estimates of average intake.
“The safest strategy right now is to limit how often you eat heavily processed foods that use these engineered palm fats, especially if they appear regularly in your diet,” Tuvé advises.
5. High-fructose corn syrup — concentrated fructose linked to liver and metabolic problems
High-fructose corn syrup (HFCS) is an artificial sweetener made from corn starch and is very common in the US. You’ll find it in sodas, breakfast cereals, yogurts, candies, and even some savory items like bread, soups, and ketchup.
HFCS typically contains about 55% fructose. Unlike glucose, which the body uses directly, fructose is metabolized in the liver, and excess fructose is more readily turned into fat. That’s why large amounts of HFCS are considered particularly harmful.
Fructose occurs naturally in fruit, but in fruit it appears in much smaller amounts and arrives with fiber that slows absorption and blunts harmful effects.
A large body of research links high HFCS consumption to nonalcoholic fatty liver disease, insulin resistance, type 2 diabetes, obesity, and cardiovascular disease. HFCS can also disrupt the microbiome: lowering “beneficial” bacteria, increasing inflammation, and weakening the gut barrier — changes that can promote weight gain, blood-sugar problems, and gastrointestinal disorders.
The World Health Organization recommends that “free sugars” — all added sugars plus the sugars in honey, syrups, and fruit juices — make up less than 10% of daily energy intake.
On labels HFCS in the US usually appears as high-fructose corn syrup; in the UK and EU it often shows up as glucose-fructose syrup or fructose-glucose syrup.
How to make healthier choices
Here are practical tips to reduce risk without aiming for perfection:
- Check the nutrition panel: salt, sugar, fiber, and the type of fat give a quick sense of whether to choose a product.
- Read the ingredient list: if a product contains many ingredients you don’t use at home, it’s likely ultra-processed.
- Don’t fixate on a single additive: overall diet quality matters more — favor fresh or minimally processed foods when possible.
- Allow yourself favorite treats sometimes: total frequency and portion size matter more than complete avoidance.
Ultimately, the best approach is to learn how to recognize ultra-processed foods and reduce their role in your daily diet rather than aim for an unrealistic total ban. Reading labels and making conscious choices will cut harm while letting you keep the pleasures of food.
Based on material from BBC Science Focus
Photo: Openverse, Unsplash
