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  • Writer's pictureIsabel Hemmings

Is our reliance on processed food making us sick?

Updated: Oct 2, 2023

We have seen a tsunami of ill-health and obesity in recent years, with a huge rise in the numbers of people who suffer from one or more chronic disease, such as obesity, diabetes, cancer, coronary heart disease and Alzheimer’s Disease. But why has this happened? This serious down-turn in our health closely mirrors the massive changes we have made to our diets in recent years. Over half the food we eat in the UK is ultra-processed, including fast foods, foods high in sugar and refined carbohydrates and processed fats. The facts are surprising and shocking, and action is urgently needed.

The rise in obesity

As recently as the 1970’s fewer than 3% of adults were obese with just 16% of women and 25% of men either overweight or obese (1). Today, 28% of adults in this country are obese, and 64% either overweight or obese. As shown in the diagram below, three quarters of adults aged 45-74 in England are now either overweight or obese (2). Added to that, nearly 10% of 4-5 - year olds are obese, and by age 10-11, this figure rises to 21%. What makes these figures particularly shocking is how quickly these changes have happened – forty years ago obesity was extremely rare, and now it’s one of our biggest health threats.

The rise of chronic disease

Alongside these dramatic changes in weight, in recent years we have also seen a huge rise in many other chronic, or non-communicable diseases (non-infectious), including heart disease, cancer and neurodegenerative conditions such as Alzheimer’s Disease. The number of people in the UK with diabetes has grown five-fold since the eighties, and now nearly 5 million people have this condition, with many more having pre-diabetes or insulin resistance. On average diabetes is responsible for 530 heart attacks and 175 amputations each week in the UK (3). And whilst deaths from heart and circulatory disease had previously fallen due to a reduction in the rate of smoking, since 2014 deaths from these diseases have been on the rise again (4). Other than smoking, the major risk factors for heart disease are obesity, diabetes and high blood pressure.

The change in our diet and the rise of ultra-processed foods

The number one culprit for our worsening health appears to be our diet. Much of the food we eat today is highly processed, with high sugar and refined carbohydrate content, and made with industrial fats and added chemicals These are the packaged foods in our supermarkets which are heavily marketed to us by the food industry. They are the convenience foods we use because we’re short of time, which Michael Pollan describes as ‘edible, food-like substances’ and by the Global Panel (5) as follows:

‘They typically contain little or no wholefoods, are ready-to-consume or heat up and are fatty, salty or sugary and depleted in dietary fibre, protein, various micronutrients and other bioactive compounds.

Forty years ago, we ate very little fast food, pizza and pasta were rare, and sweets, cakes and soft drinks were considered occasional treats. Meals were generally cooked from scratch at home and we usually ate three meals each day, generally without snacks. Over the last few decades our diets have changed dramatically - we switched from eating real food to eating huge quantities of ultra-processed foods. Food manufacturers came to dominate the way we ate, replacing traditional home-cooked food with convenience foods (6). Over time, convenience foods crept up on us, becoming part of our lives, depleting the nutritional value of our food and leading us to consume much more sugar (7).

How does ultra-processed foods affect our health?

At a national level intake of ultra-processed foods appears to be associated with obesity - the greater the consumption of ultra-processed foods (UFPs), the higher the level of obesity. One study showed how the UK had both the highest consumption of ultra-processed foods in Europe and also the highest levels of obesity (8).

When we eat ultra-processed foods we end up eating more. One well-controlled randomised study found that those eating an ultra-processed food diet ate on average 500 more calories per day compared to those eating a real-food diet (9). It remains unclear why people eat more when they eat these foods, however the softness of the texture and the palatability of these foods is thought to contribute to over-consumption.

Eating highly processed foods appears to increase risk of a number of diseases. A study in Brazil found that teenagers eating more ultra-processed foods had higher rates of metabolic syndrome (10). Another study followed nearly 15,00 Spanish university graduates over 9 years and found that those who ate the highest amount of ultra-processed foods were most likely to suffer hypertensive (high blood pressure) episodes (11). The large prospective NutriNet Sante study found that ultra-processed food intake was associated with overall cancer risk and increased breast cancer risk (12).

Nutrient depletion

As well as increasing risk for obesity and a range of other chronic diseases, higher intakes of ultra-processed foods reduces intake of important nutrients, such as vitamins and minerals (14) School children in one study were found to have poor dietary quality when eating larger quantities of processed and ultra-processed foods (13). Given the high proportion of ultra-processed foods eaten in the UK, it is perhaps unsurprising that national Nutrition and Diet Survey describes significant nutrient deficiencies in the UK population, particularly amongst teenagers (15).

So, what do we do?

We believe that the way forward is to eat real food, the kind our grandparents would recognise – fresh foods, cooked from scratch, using simple ingredients. Avoiding foods that come in boxes, with long lists of ingredients, including chemicals and additives to increase shelf-life, and instead selecting fresh fruit, vegetables, meat, fish, dairy and traditional fats as the basis for our diets. Making this change will help us to reverse the tide of obesity and chronic ill health.


1. Harcombe, Z, 2010. Columbus Publishing The Obesity Epidemic,

3. Whicher, CA, O’Neil,S & Holt, RIG 2020 Diabetes in the UK, 2019’. Diabetic Medicine DOI: 10.1111/dme.14225

5. Global Panel, (2016) Food Systems and Diets: Facing the Challenges of the 21st Century. London: Global Panel. Available at: (Accessed: 22 October 2018

6. Moubarac, J-C, Batal, M Louzada, ML, Steel, EM, (2017), ‘Consumption of ultra-processed foods predicts diet quality in Canada’, Appetite 108 pp. 512-520. doi:

7. Steele, EM, Baraldi, LG, Louzada, MLD et al, (2016), ‘Ultra-processed foods and added sugars in the US diet: evidence from a nationally representative cross-sectional study’. BMJ Open, 6. pp. 1-8. doi: 10.1136/bmjopen-2015-009892.

8. Monteiro, CA, Moubarac, J, Levy, RB, et al (2017) ’Household availability of ultra-processed foods and obesity in nineteen European countries’, Public Health Nutrition 21 (1) pp.18-26. doi:10.1017/S1368980017001379.

9. Hall, KD et al,2019 ‘Ultra-processed diets cause excess calorie -intake and weight-gain: An in-patient randomised controlled trial of ad libitum food intake’. Cell Metabolism. Vol 30 issue 1.

10. Tavares LF, Fonseca SC, Garcia-Rosa ML et al. (2011) ‘Relationship between ultra-processed foods and metabolic syndrome in adolescents from a Brazilian Family Doctor Program’. Public Health Nutrition 15, pp. 82–87 doi:

11. Mendonca R.D. et al, 2017. Ultra-Processed Food Consumption and the Incidence of Hypertension in a Mediterranean Cohort: The Seguimiento Universidad de Navarra Project. Am. J. Hypertens.;30:358–366. doi: 10.1093/ajh/hpw137

12. Fiolet T., et al 2018 Consumption of ultra-processed foods and cancer risk: Results from NutriNet-Sante prospective cohort. BMJ. 2018;360:k322. doi: 10.1136/bmj.k322.

13. Cornwell, B, 2018 Processed and ultra-processed foods are associated with lower quality nutrient profiles in children in Columbia. Public Health Nutrition, Vol 21 Special issue 1

14. Chantal, J, et al, (2017) ’Contribution of ultra-processed foods in the diet of adults from the French Nutri-Net-Sante study’, Public Health Nutrition 21(1). pp 27-37. doi: 10.1017/S1368980017001367.

15. National Diet and Nutrition Survey, available at:

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