We all know freshly prepared, nutritionally balanced meals are best for us and processed foods should ideally be restricted to the occasional treat. Yet experts warn us ultra-processed foods or UPFs are a growing health hazard. The term, introduced in 2009 by a group of Brazilian researchers, describes the most industrially compromised foodstuffs. But what exactly are they – and what's so bad about them? 

Click or scroll through our gallery to discover what UPFs are, and the foods experts say we should avoid the most.

We've based our ranking on the health credentials of each food, taking guidance from a registered nutritionist.

These ingredients are manufactured for low cost and convenience and deployed in complex formulations to make 'hyperpalatable' snacks and meals. "This processing completely changes the structure of food," says registered nutritionist Dr Lucy Williams. "We need food to actually work for us; it drives our biology so it needs to fuel us, rather than just satisfy our appetite." UPFs displace healthier foods from our diet, filling us up (and encouraging us to overeat) without delivering our essential nutrients. Now, a growing body of studies suggest diets high in UPFs are causing significant harm to public health. 

Unless you're willing to radically redesign your life it's incredibly hard to cut out UPFs entirely. Industrially manufactured foods are engineered around our busy lives and tight budgets, so it's not surprising we've become addicted. What we can do is shop more mindfully. "My rule of thumb is look at the label," says Dr Williams. "If you don't recognise an ingredient as one you'd put in your kitchen cupboard, do you really want to be eating it?"

Now click or scroll through our gallery to discover 23 of the most common ultra-processed foods, counting down to the most dangerous of all.

Many UPF researchers warn us to suspect foods that carry a health claim, a marketing move that generally enhances a product's profitability. When you check the ingredients in 'healthier' syrups, for example, you'll spot a barrage of artificial sweeteners which, as we'll hear further up our ranking, are bad news for our essential gut health. You'll also find some seriously complex thickeners; sodium carboxymethyl cellulose, anyone?

More familiar may be xanthan gum, a ubiquitous thickener produced as a kind of slime by bacteria that a researcher at the University of Michigan found impacts our gut microbiome. With these syrups, sometimes marketed as 'keto-friendly', showing up in barista coffees, desserts, ice creams and more, it pays to ask questions about your low-sugar treat. Just remember that 'zero sugar' isn't a green light, nutritionally speaking.

What could be tastier than a roast dinner or a hearty plate of Swedish meatballs smothered in gravy? Well, UPFs are sneaking into your granules – with flavour enhancers, modified starches and emulsifiers such as soya lecithin introduced to recreate the silky finish of a rich, homemade sauce. "If you take fat out you have to put an emulsifier in to give back that lovely mouthfeel," says Dr Williams. "But there's really good research to show those gloopy ingredients impact our gut microbiome."

While instant gravy mixes are convenient when your slow-cooked meat dish or nut loaf needs a moistening sauce, there are alternatives that can lower your exposure to UPFs. Umami-rich stocks made from soaked porcini mushrooms, kombu or indeed meat juices can be thickened with unmodified starches such as cornflour without compromising health.

Besides a high quantity of sugar and other refined ingredients, this toast topper almost always contains palm oil, an ingredient that's gained a bad reputation for the deforestation caused by palm plantations. There's another reason to avoid its processed form, though. "When freshly pressed, it’s an almost luminous crimson, highly aromatic, spicy and flavourful, and full of antioxidants like palm tocotrienol," says Dr Chris Van Tulleken, a UPF expert and author of Ultra Processed People. Doesn't sound like the chocolate spread you eat?

That's because the palm oil we encounter in UPFs has been through some huge changes: 'refined, bleached and deodorised', as Dr Van Tulleken puts it. But it doesn't have to be that way. Some commercial chocolate-flavoured nut butters just combine nuts, agave syrup and a little oil with cocoa powder. Or you could make your own chocolate spread at home with a mix of dairy butter, cocoa and a little sugar.

It may surprise you, but these healthy-sounding dessert alternatives aren't always the wholesome choice they appear. Expect to find modified starches, thickening agents, artificial sweeteners, gelling agents and emulsifiers, especially in the low-fat options where manufacturers have worked hard to replicate the mouthfeel of full-fat dairy. So why are UPF yogurts so common, and why are they advertised as a healthy choice? 

"In the 1980s there was a surge in chronic diseases like cancers and heart disease which was assumed, without evidence, to be caused by fat," says Dr Williams. Manufacturers keen to give a traditional ingredient a modern makeover did a great job convincing us that low-fat choices are more compatible with a healthy, active lifestyle. "Buy plain yogurt and add your own fruit," is Dr Williams' advice.

It's no wonder people fell in love with packet soups; an instant meal reconstituted straight from a powder is a kind of magic. Unfortunately, it's the kind that requires disodium 5'-ribonucleotides (a kind of salt made from two E numbers) and glucose syrup. A packet 'vegetable' soup can contain as little as 1g of fibre in a 250g serving, while giving us the impression of being a healthy choice. 

If instant soups are a big part of your life, take a look at the labels. Their low cost and high convenience is inviting a whole lot of ultra-processed ingredients into your diet. Ditch them in favour of fresh alternatives from the chiller cabinet, or consider instant miso sachets for a nutritious lunch courtesy of your kettle.

This kids' favourite, often advertised as being made exclusively from 100% breast meat, isn't always what it seems. Known technically as a 'comminuted meat product', which means it's reformed from tiny fragments, the soft bites commonly hover around 50% actual meat content. Worryingly, a US study found levels of actual lean muscle are often much lower. The fried, bleached wheat coating is high in refined vegetable oil, another ultra-processed ingredient.

The refined and degraded seed oils in nuggets – and many UPFs – are a particular problem. "Omega 3 is a great anti-inflammatory," says Dr Williams. "But oils in ultra-processed foods tend to be very low in omega 3 and high in omega 6. Again, it's a displacement thing: you're losing the oil you really need in your diet and getting too much of a different one."

You know you're in trouble with a jar of mayonnaise when starch appears higher up the ingredients list than egg. But then, creating a spoonable thick emulsion without the classic constituents of oil and yolk is a conundrum. Food technicians have cracked it by using gums and starches to magically make water and a few flavourings feel oily in your mouth. 

You could consider this condiment a classic example of a UPF. A homemade mayo uses four ingredients. A leading low-fat brand? Seventeen. If you're on a mission to reduce the fat in your diet, you might consider saving mayo for the occasional treat. Choosing a low-fat option will inevitably bring a long list of industrially adapted ingredients into your meal.

Protein makes a great basis for a snack, but the challenge to cram it into a tasty and convenient bar sees many manufacturers employing a cocktail of components a world away from their whole food origins. Turning soy or pea protein (and a host of additives that may include lecithin, starches and even bovine collagen hydrolysate) into an appealing snack isn't easy; these bars are often high in sugar and fat and relatively low in fibre.

If protein bars are powering you through your workouts, it's worth considering the impact on your health. With recent studies showing that UPFs may increase the risk of depression and type 2 diabetes, refuelling with these snacks may be impacting your reasons for exercising in the first place. A simpler protein snack – maybe a handful of raw nuts, a hard-boiled egg or plain yogurt – will help you hit your macros without serving up a long list of additives.

"I'd avoid 99% of fast foods," says Dr Williams. "Many have trans fats: fats or oil that have been synthetically altered." Banned in some parts of the world, but only restricted by voluntary agreement in others (including the UK), trans fats are linked to higher risk of stroke and heart disease thanks to their impact on unhelpful cholesterol. So why are fried foods such a problem? 

Trans fats are sometimes created deliberately through 'hydrogenation' – a process that slows the deterioration of oils. But they can also occur when fats or oils are raised to high temperatures, for example in deep fat fryers. Baked fries made with a spritz of olive oil or crisped in an air fryer can be much tastier, and healthier too. Go easy on the salt, though – it's a major risk factor in cardiovascular health.

Cheaper biscuits, cakes and pastries can be hiding places for all kinds of UPFs. According to the British Dietetic Association, spotting partially hydrogenated fats or oils on a label means that food 'will almost certainly contain trans fats too'. The higher up the ingredient list they appear, the more trans fats the product will likely contain. They may also be declared as 'mono and diglycerides of fatty acids', says Diabetes UK.

All this is pretty disappointing if you've selected an oaty snack hoping for a slow release of energy. "A carbohydrate is basically a long chain of simple sugars all joined," says Dr Williams. "The longer that chain, the more slowly we digest it – so the healthier it is for us. The more processed a food is, the more of that breaking down has already been done, so we absorb the sugar really quickly." A homemade oat flapjack that's low in sugar is a much better option.

Sugar taxes have done a great job of encouraging manufacturers to reformulate drinks, but do check what's now bringing the sweetness to your favourite fizzy pop. "Artificial sweeteners are a big no for me," says Dr Williams, who points to a slew of emerging research reporting negative impacts on the all-important gut microbiome and subsequent ramifications on how our bodies metabolise sugars.

"We know if we consume something like a fizzy drink with artificial sweeteners in and consume a meal straight after, we'll absorb more sugar from that food," says Dr Williams. "They play havoc with our biology and confuse our gut, so I'd avoid anything with artificial sweeteners in." If aspartame, sucralose, acesulfame K, saccharin or other common sweeteners crop up on the label, consider a swerve.

Chocolate itself is not a UPF, but the type contained in (or topping) your average biscuit almost certainly is, and will contain refined fats, sugar and emulsifiers. Add the ingredients of the bake itself and you have a problem. "Once in our gut, the additives and high sugar content make a really poor environment for our digestive microbes," says Dr Williams. "Our gut health impacts our whole health. About three quarters of our immune system sits in the wall of our gut and is regulated and controlled by our gut microbiome."

That precious microbial population in our gut influences everything from our levels of disease-triggering inflammation and how well our immune system works, to our mood. "When our immune system isn't well regulated it can go into overdrive. That's what inflammation is, and it's at the root of type 2 diabetes, heart disease and cancer." Seek out biscuits with high cacao, low-sugar chocolate and minimal ingredients for a better snack.

As you'll be gathering, it's often when a natural ingredient is being synthesised that foods turn into an 'industrially produced edible substance', to echo Fernanda Rauber, one of the original Brazilian researchers looking into UPFs. The resulting products can be aspirational and expensive, as in the case of faux meats. Often lower in fibre and higher in saturated fat, salt and sugar than simpler options like tempeh and tofu, plant-based meat substitutes require a thorough label check.

Some meat replacements are worryingly low in protein, but there's more. Researchers in the UK found that while adding minimally processed plants to our diet reduces the risk of cardiovascular disease (and particularly deaths from this condition) by up to 14%, choosing plant-based UPFs has the opposite effect. While plant foods are often given a 'health halo' by producers, relying on ultra-processed options carries a significant health risk.

OK, no one turns to sweets for a healthy hit of nutrition, but all confectionery is not created equal. The original classification of ultra-processed foods highlighted those with five or more ingredients, and a quick glance at a few filled chocolate bars shows the leading products tend to have triple this number. The presence of glucose-fructose syrup, typically made from starch, is problematic, too, described by researchers as delivering a 'one-two punch to health'.

'Clean label' confectionery – products made with natural colours, flavourings and preservatives – is a growing category, so check labels to spot more familiar-sounding ingredients. Many will contain sugar, but manufacturers keen to court worried shoppers are increasingly using plant extracts (including turmeric, beetroot and carnauba wax) instead of industrially compromised nasties. Just remember to keep all confectionery to a minimum to avoid the ill effects of even healthier versions. 

Deep-fried slices of fresh potato seasoned with a little salt are a processed indulgence, but it's the reconstituted starch or puffed maize snacks with tongue-shocking flavours that many of us really crave. So, once we've popped, why is it so hard to stop? Research suggests it's the flavour enhancers (monosodium glutamate, for example) regularly deployed in these ultra-processed crisps that help transform a nutritionally bankrupt puff of starch into something we can't resist.

"These kinds of snacks are high in energy but low in nutrients," says Dr Williams. "You're getting all the sugars without the goodness, which just increases our appetite further." To break the addictive snacking cycle, consider options with added benefits: raw nuts with a little salt and pepper or toasted seeds with a sprinkling of soy sauce. Your body will thank you.

Cereal seems like a great brekkie option: whole grains lock carbohydrate up with fibre and micronutrients, causing energy to be released slowly as we digest. The perfect choice to keep hunger at bay, right? Not exactly. "When a carbohydrate is processed, the sugars within are already broken down, so we absorb them too quickly," says Dr Williams. And that's not all...

These damaging sugar spikes may be 'clean-washed' (given a more wholesome marketing spin) in UPF cereal via added nutrients proudly advertised on the label. "Kids' breakfast cereals are a good example where vitamins and minerals (for example calcium or iron) are stripped from foods during processing but then added back in so they're technically in the food," says Dr Williams. "The truth is we don't know how well we can absorb them in this isolated form." 

How is it that a frozen pizza can deliver 60% of your daily saturated fat allowance – but absolutely none of your fibre? Because it's often formed from highly processed cheeses, meats and dough, plus stabilisers and preservatives. Even premium, high protein and free-from options are often UPF hotspots, with toppings such as 'non-dairy sunflower oil-based food preparation', hydrolysed vegetable protein, or chicken breast that in turn contains 'dextrose, salt, maltodextrin, maize starch, rice flour and concentrated lemon juice'.

A simple swap could be filling your freezer with the most basic Margherita you can buy (or make) and then freezing chopped portions of mozzarella, cooked peppers and onions and even pineapple chunks. Shun ultra-processed meat or veggie protein pieces for beef strips, chicken or tofu and you've significantly reduced the UPFs in a speedy midweek dinner. Add even more veg and you're starting to offset the impact of that refined white flour.

Did you have ice cream this high on your UPF score card? The expense of transporting a delicate blend of pricey natural ingredients (traditionally cream and egg yolks) from the manufacturing plant to the wholesalers to the retailer, all at around -18°C, means some ice cream producers often take serious shortcuts. Re-freezable 'blocks of foam stable at room temperature' is the aim of some manufacturers, according to Dr Van Tulleken's book, Ultra Processed People. 

To understand what you're eating, check out the ingredients in your ice cream, and remember options enhanced with cookie dough, sprinkles, swirls of sauce or crushed biscuits may pack even more ultra-processed ingredients. Vegan formulations and mainstream brands are often the worst offenders; by contrast, small local producers may use as few as three simple ingredients to make their ice cream.

Here's a huge source of the UPFs in our fridges. An estimated 91% of UK shoppers buy chilled ready meals and, while standards have improved, you'll still find gelling agents, preservatives and meals that are higher in sugar than essential dietary fibre. "And fibre is a key one," says Dr Williams. "Gut microbes feed on it, and when you think that 80% of our immune system sits in the gut wall regulated by our microbes, you realise what we're missing out on."

That aforementioned sugar is a big problem, too. "We get very quick energy from the sugar – it creates a sugar spike in our blood – and when that comes down really rapidly it stimulates the appetite and makes us want more," says Dr Williams. "So with sugary foods we're quite often left hungry quite soon after eating. We know people eat more quickly when they're eating UPFs because they're so easy to eat, and that way we eat more, so everything's stacked against you."

How much bread do you eat? It's a staple in diets around the world, but the vast majority of the bread on supermarket shelves and in pre-packed sandwiches qualifies as a UPF. "Industrially produced bread has a lot of refined carbs, additives for shelf life and added yeasts," says Dr Williams, who suggests these strong commercial yeasts carry on fermenting in the stomach, causing some people discomfort. And it's not just white bread, either; many 'brown' breads use caramel colouring to give the appearance of wholemeal without the texture, and that's an issue…

"Fibre is a really key nutrient to keep us healthy," says Dr Williams. "A varied intake is one of the best things we can do for our bodies. If we're not getting that fibre to begin with, because it's been broken down by processing, that's a real problem." Check labels to discover the fibre content in your loaf or make your own. And remember – true sourdough is made from just flour, salt and water, so beware of 'sourfaux', a UPF imitation.

They may be highly convenient, but these instant pot snacks earn a high ranking thanks to their worrying ingredients. While instant noodles themselves are typically low in fibre, full of additives and fried during production to speed up cooking times, the accompanying sauce or soup sachet is also often high in sodium.

Research conducted in the US found significant consumption of instant noodles increases the risk of cardiometabolic syndrome, which can lead to heart disease, diabetes and stroke. This could be particularly worrying given the increasing demand for this speedy snack – according to data from the World Instant Noodle Association their consumption is growing fast across the globe.

A hidden UPF that's absolutely everywhere in pre-prepared foods, margarine is a strong candidate for the very first ultra-processed food. Early trials to make these semi-solid blocks took place in 1869, and margarines are another modern miracle of science. They're predominantly made from liquid vegetable oils blended with emulsifiers, preservatives and water. Common in manufactured products of all kinds, margarine also pops up in our home cooking, making it almost impossible to avoid.

"The single most important thing we can do for our health is to improve the variety of gut microbes we have," says Dr Williams. "Emulsifiers have been shown to do the opposite." The margarine category has been a lucrative battleground for manufacturers, with plenty of health claims made, but it's worth noting that pricier plant-based and nutrient-fortified options often have the most complex formulations.

Top of our ranking for good reason, hot dogs and other highly processed meats are categorised alongside fellow carcinogens such as tobacco by The International Agency for Research on Cancer. This is partly thanks to nitrates and nitrides (additives that help these savoury products live longer in our fridges). When researchers from the University of Michigan set out to calculate the dietary changes that would have the most benefit for health and the environment, their scrutiny across a complex set of metrics left processed meats nowhere to hide.

While hams and bacon are processed, reconstituting that meat into a frankfurter hikes the health risk even further. The study concluded that eating a hot dog could knock 36 minutes off a healthy lifespan, while swapping it for a serving of nuts could add 26 minutes. With research also suggesting that cooking processed meats at high temperatures releases further cancer-causing chemicals, barbecue hot dogs no longer seem anywhere near as appetising.

Now discover the best and worst vegetables according to nutritionists