Diet of highly processed foods affects your brain: study

You know eating highly processed foods are bad for your waistline, but it seems they’re also damaging your brain.

A study released this month and published in the Jama Network investigated the association between ultra-processed foods and cognitive decline. The results were startling.

The study found there was a 28 per cent decline in brain function for people who regularly ate highly processed foods.

Harvard University defines ultra-processed foods as foods made mostly from ‘extracted’ products such as fat, starches and added sugars. Examples include cakes, processed meats, fast foods, sweetened breakfast cereals, packaged soups and soft drinks.

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The study examined 10,775 subjects in three waves about four years apart from 2008–2017 and began with an average baseline age of about 51.

During the follow-up, individuals with a diet high in ultra-processed food showed a 28 per cent faster rate of cognitive decline than the rest of the cohort.

Neuroimaging found that high consumption of a western dietary pattern was related to a reduction in the left hippocampus and grey matter volume in the brain. The study also conducted verbal fluency and neuropsychological testing.

The hippocampus is a brain structure that plays a leading role in learning and memory.

Those with a diet high in ultra-processed foods were also found to have a 25 per cent faster rate of decline in executive brain function – the processes that allow us to plan, focus, remember instructions and successfully juggle tasks.

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The study noted that in the past 40 years, the food industry had increased the commercialism of ultra-processed foods.

“Such UPFs [ultra-processed foods] … contain little or no whole foods and typically include flavourings, colourings, emulsifiers and cosmetic additives,” the study states.

“Examples of UPFs are sweet and savory snacks, confectionery, breakfast cereals, ice cream, sugar-sweetened beverages, processed meats, and ready-to-eat frozen meals.

“Fifty-eight per cent of the calories consumed by US citizens, 57 per cent of the calories consumed by British citizens, and 48 per cent of the calories consumed by Canadian citizens come from UPFs.

“Consumption of UPF has also been linked to an increased risk in cardiovascular disease, metabolic syndrome and obesity.”

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The scientists used subjects from Brazil’s Longitude Study of Adult Health (ELSA-Brasil), which uses data from about 154,000 active and retired civil servants aged between 35 and 74. ELSA-Brazil began in 2008–10 and its subjects are from six Brazilian states. It was established to investigate the development and progression of chronic diseases, particularly cardiovascular diseases and diabetes.

Surveillance includes an annual telephone call, clinical investigations and face-to-face assessments.

According to Dementia Australia, dementia is the second leading cause of death in Australia and the leading cause of death in women. In 2022, up to 487,000 Australians were living with dementia and an estimated 1.6 million people were involved in their care.

Would you change your diet if you knew it would affect your brain function? Why not share your thoughts in the comments section below?

Jan Fisher
Jan Fisher
Accomplished journalist, feature writer and sub-editor with impressive knowledge of the retirement landscape, including retirement income, issues that affect Australians planning and living in retirement, and answering YLC members' Age Pension and Centrelink questions. She has also developed a passion for travel and lifestyle writing and is fast becoming a supermarket savings 'guru'.


  1. Yes, I changed my diet. I went Carnivore. It changed my life. No brain fog, I can walk again without a stick or walker as my back 99% better, I have massive amounts of energy and have lost 15.5 kilos in 11.5 months.

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