Reading time: 9 minutes

Contents

1. What ultra-processed means
2. What the new study investigated
3. What was different in the body
4. Why food structure might matter
5. What we can take from the findings
6. The practical four-question check
7. Simple everyday alternatives
8. FAQs
9. Conclusion

Every food has its own nutritional profile. The nutrition information table gives you a quick overview: it shows the energy content and the amounts of fat, carbohydrate and protein, alongside saturates, sugars and salt. This helps you compare foods at a glance and better understand their composition. Yet the numbers only tell part of the story. Two foods can have very similar nutritional values on paper and still affect our metabolism differently. How nutrients are “packaged” within a food also matters. Are they contained within intact cell structures, as in an apple, or have milling or puréeing already made them more accessible? Has the food undergone further processing? Its structure helps determine how quickly digestion releases nutrients and the body can absorb them. So your body responds both to what a food contains and to the form in which those nutrients reach it.

What does this mean for everyday life? First, it helps to remember that processed does not automatically mean ultra-processed. And ultra-processed products should not all be treated as the same.

What does “ultra-processed” mean?

Frozen spinach, plain yoghurt and tinned beans all have one thing in common: they have been processed. Spinach is frozen, milk is fermented into yoghurt using bacteria, and beans are cooked and preserved. These methods give foods a useful form and often make them safer and longer-lasting.

When researchers talk about ultra-processed foods, they usually mean more than cooking, freezing or preserving. They often use the NOVA classification, which groups foods according to the extent and purpose of processing. Ultra-processed products are generally industrial formulations assembled from individual food components. These may include isolated proteins, modified starch, sugars and fats, often combined with flavourings, colourings or emulsifiers. The resulting recipes involve ingredients and processing methods rarely used in an ordinary kitchen. Typical examples include many soft drinks, confectionery, packaged snacks and certain ready meals. However, classification is not always straightforward: packaged wholemeal bread, a plant-based drink or a protein bar may also fall into this category, depending on the recipe. The label alone therefore does not tell you how nutritionally balanced a product is.

What a new study investigated

Can the body respond differently to two meals with comparable nutritional values? A study published in Nature Metabolism in 2026 investigated this question in 57 healthy adults of normal weight. The researchers compared an ultra-processed meal with a meal that was not ultra-processed. The meals were matched for factors including energy content, amounts of fat, carbohydrate and protein, and glycaemic index. The study used a randomised crossover design: participants ate both meals on separate occasions, with the order assigned at random. This allowed the researchers to compare each person's response to the two meals.

The team measured metabolic responses in particular detail in some participants. They also used functional magnetic resonance imaging (fMRI) in a subgroup to examine how the brain responded to food cues. This technique provides an indirect measure of changes in brain activity.

The study aimed to answer a specific question: does processing make a measurable difference to a meal's effects, even when key nutritional values are comparable?

What was different after the ultra-processed meal?

Blood glucose responses were comparable after both meals. Nevertheless, the body released more insulin after the ultra-processed meal. There were also differences in short-term changes in energy expenditure and in how much carbohydrate the body used for energy.

Insulin helps move glucose from the blood into cells and helps regulate how the body uses nutrients after a meal. Put simply, blood glucose followed a similar pattern, but the hormonal regulation behind it differed. A similar blood glucose curve therefore does not automatically mean an identical metabolic response. However, a single instance of higher insulin release is not, in itself, evidence of disease.

The researchers also found differences in the brain's response to food cues. Certain metabolic responses were associated with activity patterns in brain regions involved in reward and motivation. 

Why might food structure matter?

Nutrients do not simply sit alongside one another within a food. They are embedded in a network of cell walls, fibres and other components. Scientists call this structure the food matrix. Think of it as natural packaging: it influences how easily digestive enzymes can reach the nutrients.

An apple is a useful example. When you eat it whole, you need to chew it and break down its cell structures. Puréeing does some of that work in advance. Much of the nutritional content remains, but its “packaging” changes. Milling, heating and other processing methods can also alter the food matrix. This can make starch, fats or proteins more accessible to digestion. Texture often changes too: a soft meal can usually be eaten more quickly than one that requires thorough chewing. Fibre, water content and volume also influence digestion and how full we feel.

The study could not establish which of these properties caused the greater insulin response. However, its findings suggest that calories and macronutrients alone are not enough to predict the body's response to a meal.

How to make informed everyday choices

You do not need to classify every food by its level of processing. A more useful approach is to build most of your diet around foods whose original ingredients are still recognisable: vegetables, fruit, pulses, oats, nuts and wholegrains provide a good foundation. Processed foods can also be practical, nutritious and part of a balanced diet. Frozen vegetables without sauce, tinned beans and plain yoghurt can make everyday eating easier. What matters is how the original food has changed and what has been added.

What to look for when shopping

Check the ingredients list.
Ingredients are listed in descending order by weight. If sugar, syrup or fats appear near the top, they account for a larger share of the product. In muesli, for example, oats or other wholegrain flakes should form the base.

Compare similar products.
Nutrition information per 100 grams helps you compare two types of muesli, bread or yoghurt. Look at sugars, saturates and salt, as well as fibre where listed. Bear in mind that “of which sugars” includes naturally occurring sugars, such as those in milk or fruit. The ingredients list is more useful for identifying added sugar.

Look beyond the front of the pack.
Words such as “protein”, “fitness”, “vegan” or “with vitamins” tell you little about the overall composition. A protein bar may essentially be a sweet snack with added protein. Equally, packaged wholemeal bread is not automatically a poor choice.

For everyday life, the main message is to make balanced, minimally processed foods a habit. Sweets, snacks and ready meals do not have to disappear completely. They can have an occasional place without becoming the foundation of your diet.

The four-question check for everyday choices

You do not need complicated rules when shopping. These four questions can help you assess a product:

You do not have to make the perfect choice every time. What matters is what you eat regularly. Use this check as a guide to gradually include more foods that nourish you and fit your habits.

Simple swaps that make everyday eating easier

Eating a balanced diet does not mean cooking every meal from scratch. Small changes to foods you already buy regularly can often help:

• For breakfast: Choose oats with nuts and fruit instead of sugary granola. Add milk, plain yoghurt or an unsweetened, calcium-fortified soya alternative, and breakfast is ready in minutes.

• When choosing yoghurt: Opt for plain yoghurt and add fresh fruit or unsweetened frozen berries. That way, you decide how sweet it is.

• For a snack: An apple with a handful of nuts or a plain yoghurt makes a straightforward alternative to sweets and sweet snack bars.

• When choosing ready meals: Look for options with plenty of vegetables and a protein source such as pulses, tofu, fish or meat. Compare the salt content of similar products. Adding frozen vegetables is also a quick way to improve a ready meal.

• For drinks: Make water and unsweetened tea your everyday choices. Soft drinks can have an occasional place, but should not make up most of your daily fluid intake.

• For the cupboard and freezer: Keep frozen vegetables without sauce, tinned beans or lentils, wholemeal bread and eggs to hand. These can quickly become a meal, such as a vegetable stir-fry with egg or a bean salad served with wholemeal bread.

Start with a swap that feels easy. You do not have to give up every biscuit or remove every frozen pizza from your menu. What matters is that your daily habits provide a good foundation, with room to enjoy your food.

Ultra-processed foods: FAQs

Are all processed foods unhealthy?

No. Processing can make foods safer, longer-lasting and easier to digest. Plain yoghurt, frozen vegetables without sauce, wholemeal bread and tinned pulses can all be useful additions to your diet. What matters is how a food is processed and what it contains.

How can I recognise ultra-processed foods?

Check the ingredients list. Typical features include combinations of isolated or modified food components, flavourings, colourings and other additives you would rarely use in your own kitchen. However, a single additive or a long ingredients list is not enough to classify a food. Also consider its main ingredients, nutritional values and how often you eat it.

Are protein bars or plant-based drinks automatically poor choices?

Not necessarily. A protein bar can be convenient when you are out and about, while an unsweetened, calcium-fortified plant-based drink can be a useful addition to your diet. However, composition varies considerably between products. Compare sugars and protein in particular, along with any added vitamins and minerals. The words “protein” or “plant-based” alone tell you little about nutritional quality.

Can a single ultra-processed meal cause harm?

The study discussed here cannot tell us that. A greater short-term insulin response is not the same as damage to health. Your longer-term eating pattern matters most, alongside physical activity, sleep and other factors.

Does this mean calories no longer matter?

They still matter. Your energy intake and expenditure over time remain key to body weight. However, calories alone do not tell you how filling a meal will be or how your metabolism will respond. Food structure, fibre and protein content, and eating speed also play a role.

Conclusion: good nutrition is about more than numbers

Two meals can look similar on paper yet trigger different responses in the body. That is what the new study suggests: despite comparable calories and macronutrients, the insulin response was greater after the ultra-processed meal. Further research is needed to understand the roles of food structure and individual processing methods.

For everyday life, read the nutrition information and consider what lies behind the numbers. Vegetables, fruit, pulses, wholegrains and nuts provide a good foundation. Practical options such as frozen vegetables, tinned beans or a well-balanced ready meal can complement them.

You do not need to plan every meal perfectly or avoid particular foods entirely. The habits that shape your everyday life matter most. A simpler breakfast, water as your go-to drink or an extra portion of vegetables are all concrete steps you can start with.

References

Hutelin Z et al. Metabolic and neural responses to ultraprocessed foods: a randomized, controlled, crossover study. Nature Metabolism. 2026. Read the study.

Dicken SJ et al. Ultraprocessed or minimally processed diets following healthy dietary guidelines on weight and cardiometabolic health: a randomized, crossover trial. Nature Medicine. 2025. Read the study.

Du Y et al. Ultra-processed food consumption, plasma metabolite profile, and risk of all-cause and cause-specific mortality in a population-based cohort. Clinical Nutrition. 2024. Read the study.

Lane MM et al. Ultra-processed food exposure and adverse health outcomes: umbrella review of epidemiological meta-analyses. BMJ. 2024;384:e077310. Read the review.