Cancer doctor, Professor Robert Thomas, ‘deeply concerned’ about ultra-processed foods in kids' diets

Ultra-processed foods account for two-thirds of calories in the diets of children and teens - as a cancer doctor and nutritional scientist, this is why I am deeply concerned

A new study published today in the European Journal of Nutrition was conducted by scientists from Cambridge and Bristol universities. It looked at the diets of 3,000 children who took part in a UK National Diet Survey between 2009 and 2019.

The authors reported a huge increase in the consumption of mass-produced ultra-processed foods (UPF) over this 10 year period and predict that these trends are likely to have continued until now.  It is staggering to learn that 11 to 18-year-olds are now typically getting 66 per cent of their calories from these foods, leaving little room for more nutritious food.

White children and those from deprived backgrounds are consuming the most UPFs despite these foods often being more expensive than healthy beans, fruit and vegetables.

What are UPF's

There is no strict definition of UPF's but obvious examples include, sweets, sugary drinks, biscuits, pastries, buns, cakes and pre-prepared chips. Everyday items such as breakfast cereals and mass-produced bread can also be considered UPF's. This is because they often have extra ingredients added during production, such as emulsifiers, artificial sweeteners, colours and flavours. UPF derived from meat include burgers, deep fried coated chicken, pre-prepared meals, sausages, hot dogs, pork pie's, ham, tinned meats and nuggets. 

In the study, the biggest increase in calories came from ready-to-eat or ready-to-heat meals such as takeout and frozen pizza and burgers: from 2.2% to 11.2% of calories. The second largest increase came from packaged sweet snacks and desserts, the consumption of which increased to 13%.

Why are UFP unhealthy 

They are often high in salt, saturated fats, transfats, colours, flavourings and industrial contaminants which can cause oxidative stress and inflammation. These can effect immediate well-being in teenagers by reducing immunity making them more vulnerable to infections which keep them off school. They damage gut health causing fatigue  which reduces cognitive function and IQ, damages sleep patterns, and impairs exercise performance. In the long term they increase the risks of high blood pressure, heart disease, obesity, stroke, arthritis, dementia, skin aging and osteoporosis.

On top of their effect on weight gain, inflammation and oxidative stress they also contain carcinogens such as nitrates, nitrosamines and preservatives which increase the risk of cancer. Cheap sausages, bacon, sliced ham and tinned meats have all been linked to a 30% greater chance of premature death from any cancer. 

Furthermore, most UPF have had their fibre removed which increases and speeds up absorption of their high calorie carbohydrates and sugar content which over time contributes to raised cholesterol and diabetes.

People are often lead to believe that switching to plant based processed foods is a healthier option. However, another major study published last month showed that, while often marketed as healthy, plant-based ultra-processed foods (UPF) are almost as bad. The research published in a Lancet Journal used data from the UK Biobank study and found that eating processed plants based foods significantly increased the risk of a heart attack, stroke later in life leading ultimately to early death. These included meat-free alternatives such as some veggie sausages and burgers, vegan sausage rolls, faux chicken and nuggets, all of which can be classified as UPFs. More precisely, they found that, for every 10% increase in ultra-processed plants eaten, there was a 5% increased risk of disease. 

Further clarification came from a study from Poland which analysed the nutritional content of veggie, meat substitute and meat meals in over 50 fast food outlets across the World. Although meat has its own risks, the researchers found that overall UPF from plants in the fast food outlets carried similar health risks as the meat options.  

Unsurprisingly, these trial all show that that people who eat more UPF also ate less healthier unprocessed or minimally processed foods. Eating fresh plants such as fruit, vegetables, whole gains, nuts, seeds, mushrooms and beans significantly reduces the risk of disease. It's been estimated that for every 10% incremental increase in the amount of healthy unprocessed plants eaten there is a 7% lower risk of heart disease and stroke. Unprocessed plants are high in fibre, vitamins, minerals, protein, slow release carbohydrates.

The natural phytochemicals content helps reduce excess inflammation, improve oxidative pathways and act as prebiotics to enhance gut health. Phytochemicals can counterbalance the carcinogens, such as nitrosamines, in meat by converting nitrates to nitric oxide. Meat eaters, for example, who also have a high intake of vegetables, fruit, whole grains and spices only have a moderately increased cancer risk, as opposed to salad-dodging carnivores. 

In conclusion, making a positive step to increase healthy plants and decrease ultra-processed foods is one of the healthiest commitments you can do to help your current and future wellbeing. It is very clear that UPF from meats are the worse culprits but those made from plants are almost as bad. Based on the available evidence, nutritional guidelines promoting plant-based diets should focus not only on reducing the amount of animal-products people eat, but also on the importance of the level of processing involved in the food, and avoiding UPFs.

For those of you who are interested to read more about the evidence, underlying mechanisms of how food and lifestyle influences current and long term health, you may be interested in my latest book "How to Live".