Ultra-processed foods (UPFs) have been linked to poorer health, and this may be because certain UPFs tend to be high in salt, saturated fat and sugar. But not all UPFs are created equal and some can even make up part of a heart-healthy diet.
UPFs have become a hot topic of debate recently, with extensive media attention and a growing body of research looking into how they can affect our health. Unfortunately, this has led to mixed messages in the media which makes it difficult to know which foods to buy.
The term ‘ultra-processed food’ simply refers to how much processing the foods have been through, not how healthy they may be. While eating large amounts of high calorie, less nutritious UPFs such as doughnuts and ready-made pizzas can lead to weight gain and health problems, others can be included in a heart-healthy diet, such as wholegrain breakfast cereals. Some have even been shown to lower cholesterol, for example, foods fortified with plant sterols and stanols. Here we explain the difference.
Cooking, freezing, fermenting and drying are all forms of food processing that have been used for centuries. The phrase ‘ultra-processed’ is relatively new. It's used to describe industrial processing on a large scale to preserve foods, enhance their flavour and texture, or make sure they’re safe to eat.
At the moment in the UK, there is no agreed definition for ‘ultra-processed food’ and the term isn’t used in government dietary recommendations. In the science world, there are ways of classifying the foods according to how much processing they’ve been through. The most commonly-used system is called the NOVA system, and it splits foods into four groups.
These foods are generally in their natural state or have been through minimal processing. These may have been pressed, dried, frozen, pasteurised or fermented. This group includes:
- fruit and vegetables
- shelled nuts
- fresh or frozen fish and meat
- natural (no added sugar) yogurt.
Group 2 – Processed culinary ingredients
These foods have been through simple processing. They are used in everyday cooking and are normally eaten with other foods. They include:
- cold pressed vegetable oils
These foods have been through processing techniques such as canning or bottling to preserve them or add flavour. They are usually made from a combination of foods from groups 1 and 2, and include:
- tinned fruit
- salted nuts or meat
- smoked meats
- smoked or tinned fish
- traditionally-made bread.
UPFs are foods and drinks that have gone through several industrial procedures. They contain ingredients that we don’t tend to use at home and are only used by the food industry, such as preservatives, emulsifiers, sweeteners and artificial colours. Group 4 is a very large and diverse group of foods, including:
- sliced bread
- breakfast cereals
- pre-packaged meals
- distilled alcohol
- chicken nuggets
- pasta sauces
- flavoured yoghurts
- sugary drinks.
Group 4 makes up more of our diet than any other group. On average, 56% of our calories in the UK come from UPFs.
Recently, high profile media doctors and social media influencers have shared their experiences of eating diets made entirely of UPFs. They have all gained weight, and certain markers of health have got worse. While this makes for interesting viewing, this is ‘anecdotal evidence’ which means it’s not scientific and is not proof that UPFs are harmful.
There is also scientific research looking at the effects of UPFs. Several studies looking at large numbers of people have shown that those who eat a diet high in UPFs have higher rates of cardiovascular disease (which includes diseases such as heart attacks and strokes), diabetes, obesity and kidney disease. These studies are “observational” which means they can suggest a link, but they can’t prove that the UPFs directly cause poor health.
Studies so far have grouped all UPFs together and have not separated out different foods within the category, meaning they can’t compare the effects of wholegrains cereals with doughnuts, for example.
Why might UPFs be harmful?
While there is some evidence of a link between UPFs and poor health, there is not enough research yet to explain why. One plausible explanation is that they tend to be high in fat, saturated fat, salt and sugar – nutrients that most of us need to cut down on – and can also be low in fibre – which we should be eating more of. Meaning it’s the nutrients in the foods that could be causing health problems, rather than the amount of processing.
There are a number of other theories about how UFPs might lead to health problems, and scientists are beginning to research these. For example:
- They can be more palatable than other foods (they taste nicer), which can mean you eat more and take on more calories, leading to weight gain.
- The processing causes changes to the physical structure of the food, making them softer and easier to eat. This can mean you eat faster and end up eating more.
- They may disrupt gut microbial health (gut bacteria).
Recent media coverage may give the impression that all UPFs should be avoided. At the moment, the research is not conclusive and scientists are still researching what it is in UPFs that may be harmful to health.
The term ‘UPF’ refers to the amount of processing the food has been through, not the nutritional quality. As they include a wide range of foods, grouping them all together means that some foods can be deemed unhealthy when in fact they can be part of a heart-healthy diet. At this stage in the research, the most important thing is to follow current dietary guidelines. That means looking at the individual products, the nutrients they contain, and whether they can benefit health.
Some foods in the UPF category have been through a rigorous review process by European and British Regulatory Bodies and have been shown to help lower cholesterol, which is important for heart health.
Some foods in the UPF category are healthy in terms of the nutrients they contain and there is no evidence that they could be harmful. In fact, they are considered an important part of a heart-healthy diet. These include:
- wholegrain breakfast cereals
- wholemeal bread
- baked beans.
While butter, sugar and salt are in group two, as they have only been through minimal processing, these are foods to cut down on to keep your heart healthy. In the case of butter, fat spreads that have been through more processing can be heathier. Fat spreads made from vegetable oils contain less saturated fats and more of the healthy fats than butter, and the Government’s Eatwell guide recommends including some of these in your diet, in moderation.
Foods that are fortified with vitamins and minerals can help us reach our daily requirements for different nutrients. Staple foods that are fortified include:
- breakfast cereals – these are often fortified with iron and B vitamins
- white flour – this is fortified with iron, calcium and the B vitamins niacin and thiamine.
Foods fortified with plant sterols and stanols
Foods that contain plant sterols and stanols can be helpful for lowering cholesterol. These include:
- fortified fat spreads
- fortified dairy products.
While these foods are classed as UPFs, there is strong evidence from clinical trials that eating or drinking foods containing 1.5g to 2.4g of plant sterols or stanols a day can lower blood cholesterol by 7 to 10% in three weeks. The European Food Safety Authority and the Great Britain nutrition and health claims register have reviewed all the scientific evidence and have permitted the following health claim to be used on the labels of foods containing specified amounts of sterols or stanols:
“Plant sterols and plant stanol esters have been shown to lower/reduce blood cholesterol. High cholesterol is a risk factor in the development of coronary heart disease.”
What questions still need answering?
The main questions that need answering are how UPFs affect health, and how the effects vary for different foods within the category. And also whether the effects are due to the processing, particular ingredients within the products or simply the levels of specific nutrients that they contain (their nutritional profile).
While we wait for the research into what in UPFs is causing health issues, you can use these practical tips for choosing a healthy diet.
Cook more meals from scratch
Cooking from scratch will reduce the amount of UPFs in your diet. It also puts you more in control of what you’re eating so you can eat less salt, saturated fats and sugar. By using more wholegrains you can get more fibre too. Keep an eye on your portion sizes and the types of ingredients you’re using.
Cooking from scratch doesn’t need to be time consuming. If you shop in advance and use simple recipes you can speed up the process.
Check the labels
Cooking from scratch for every meal is not a realistic option for most of us, so comparing labels is helpful when buying packaged food. Check the labels and choose foods that are lower in saturated fat, salt and sugar, and higher in fibre.
The front of pack is often colour coded which reflects some of these nutrients per 100g, while the back of pack often contains the information per serving, and also displays the fibre content. Looking at portion information is really helpful as it reflects what we actually eat, and it can be particularly helpful when choosing between products such as fat spreads, soups, breakfast cereals, cooking sauces, dressings and ready meals.
Look at your diet as a whole
The occasional ready meal or shop-bought cake is unlikely to cause a problem if the rest of your diet is healthy – with lots of wholegrains, fruits, vegetables and healthy proteins such as beans and lentils. If you think you are eating too many UPFs, gradually swap these for less processed foods. Make these changes slowly so the new food becomes a normal part of your diet before you move on to the next swap. This will help you stick to the changes in the long term.
Many pre-packaged snacks are highly processed and high in fat, saturated fat, salt and sugar. Swap some of your ready-made snacks such as cereal bars, cakes and crisps for healthy options such as satsumas, apples, plain nuts or carrots and hummus. You can also check the labels for snacks that are lower in saturated fat, salt and sugar.