What is ultra-processed food doing to our bodies?

Ever wondered why we eat ultra-processed food or what it could be doing to our bodies? Dr Sam Rodgers explains all. 

Deep down, many of us would agree that ultra-processed food isn’t something that we’d consider to be healthy. But what if ultra-processed food is more than just unhealthy? What if it’s linked to early death and poor health [1]?

Dr Sam Rodgers has a closer look at what ultra-processed food is and, more importantly, what it could be doing to our bodies. 

What is ultra-processed food?

Would you be shocked to know that more than half of the calories the average person in the UK eats come from ultra-processed foods[2]? Clever advertising, wholesome packaging, and the fact that it tastes so good (perhaps), all convince us that ultra-processed food is just part of twenty-first-century living.

To understand where ultra-processed foods sit within our diet, we’ll start by explaining the four main groups – unprocessed and minimally processed, processed culinary ingredients, processed and ultra-processed food.

  1. Unprocessed and minimally processed – these foods are our whole foods or those with very minimal processing. It includes what we'd think of as healthy foods like fruit and vegetables, nuts and seeds, and animal products like eggs, fish, and milk. They make up 30% of the calories eaten in a typical UK diet [3].
  2. Processed culinary – foods in this group are not meant to be eaten alone. Usually, you’ll mix them with foods from group one and they include oils, butter, vinegar, sugar, and salt. They make up around 4% of the calories we eat in the UK.
  3. Processed - processed foods are usually the products of mixing ingredients from group one and group two. They include cheese, fresh bread, beer, and wine and contain ingredients that we all recognise. This group makes up around 10% of calories eaten in the UK.
  4. Ultra-processed – you probably won’t recognise the ingredients list as they’ll most likely be the names of certain chemicals, colourings, sweeteners, and preservatives. They include industrialised bread, pre-packaged meals, breakfast cereals, sausages, biscuits, crisps, soft drinks, and the list goes on. Ultra-processed food makes up 56% of calories eaten in the UK.

Why do we eat ultra-processed food?

In May this year, Dr Chris Tulleken’s BBC programme called What Are We Feeding Our Kids investigated this very subject.

Dr Tulleken recognised that there is little research into how ultra-processed foods interact with our bodies, especially among children and teenagers. Throughout the show, Dr Tulleken upped his calorie intake of ultra-processed food from 30% to 80% - an average diet for one in five people [4] in the UK. Though his experiment is not a representative sample, his findings were like other studies.

On the scales, Dr Tulleken gained almost 7kg in four weeks, moving from a healthy weight to being overweight. As a result of his new eating habits, he reported poor sleep, heartburn, unhappy feelings, anxiety, sluggishness, constipation, and low libido.

Chris’ brain scans showed that the areas responsible for reward had linked up with the areas that drive repetitive, automatic behaviour, which is a similar brain response to taking substances considered casually addictive like cigarettes, alcohol, and drugs.

How does ultra-processed food affect blood tests?

In 2019, Dr Kevin Hall, a senior investigator for the National Institute of Health, tested two diets that matched fat, sugar, salt, and fibre content. The difference was that one diet was full of unprocessed foods and the other of around 80% ultra-processed foods [5].

Within the study, people were able to eat the foods on offer until they wanted to stop. Dr Hall found that people eating the ultra-processed diet ended up eating over 500 calories per day more and gained almost a kilo of body weight over two weeks.

Blood tests showed an increase in the hormone responsible for hunger and a decrease in the hormone that makes us feel full among the participants eating the diet high in ultra-processed foods. These results were consistent with Chris’ experience – his hunger hormone increased by 30 % during the experiment, which may have encouraged overconsumption.

Hall found people on the ultra-processed diet ate more quickly than those on the minimally processed diet, which may have contributed to them eating more calories. Previous studies have suggested eating more slowly may decrease hunger [6].

Does this mean we should only eat whole foods?

Processed doesn’t always mean bad. Some people would argue that most foods in moderation are good – what with variety being the spice of life and all.

A survey by the British Nutrition Foundation found that 63% of people agree with the statement that it’s better to cook from scratch than use processed foods. However, we may not have the time, the money, or the demand to cook from scratch in the 21st century. It’s much harder to make home-cooked meals if you’re living alone, with a highly demanding job and are on a low income.

While ultra-processed food includes what we may call junk food, like confectionary, fried snacks, cakes, and sugary drinks, it also includes healthier options like baked beans, fish fingers, low-fat yoghurts, and wholemeal sliced bread [7]. Yet, as around 28% of adults in England are obese and 36% are overweight [8], we don’t think that empowering people to become more mindful about their eating habits and what ingredients have gone into their food is a bad thing.

How to identify ultra-processed food:

  1. Recognise the ingredients? – If there is a long list of ingredients that you don’t recognise, you may be faced with an ultra-processed product.
  2. Long shelf-life? Have a sense check of how long the food will last. If a cake has a five-year shelf life, then what exactly is going into it?
  3. Are you craving this food? - Some foods, including ultra-processed pizzas, chocolate, crisps, and cakes, can elicit cravings, loss of control, and inability to cut back [9].
  4. Heavenly levels of satisfaction? - Many ultra-processed foods have gone through focus groups to make them ‘perfect’. The taste, level of saltiness, mouthfeel, chew, and even the sound it makes when eaten may have been fine-tuned. Could a side-effect of delicious food be that it’s hard to stop eating?
  5. Are you using this food as a reward? - A brain imaging study suggests the more often you experience rewards from foods, the more you must consume to sustain the same enjoyment [10].

Blood tests for a general health check

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  1. https://www.bbc.co.uk/news/health-48446924
  2. https://www.bbc.co.uk/food/articles/what_is_ultra-processed_food
  3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5986467/
  4. https://bmjopen.bmj.com/content/9/10/e027546
  5. https://pubmed.ncbi.nlm.nih.gov/31105044/
  6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3544627/
  7. https://www.bbc.co.uk/food/articles/what_is_ultra-processed_food#:~:text=More%20surprising%20to%20some%20will,used%20as%20dairy%20milk%20substitutes. 
  8. https://commonslibrary.parliament.uk/research-briefings/sn03336/
  9. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4334652/
  10. https://pubmed.ncbi.nlm.nih.gov/22338036/

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