Ready-made pizza & co.: How fast food damages the brain

In the 15th Nutrition Report of 2023, the German Nutrition Society defines ultra-processed foods (UPF) as "foods and beverages whose production involves extensive industrial processing of the raw materials used and which generally contain a large number of additional ingredients, in particular additives (e.g. flavorings, preservatives, colorants) and energy-rich ingredients with low essentiality (saturated fatty acids, sugar)." [1]

The report shows a link between UPF and overweight/obesity, hypertension, type 2 diabetes and cardiovascular disease. The latter includes stroke, which in turn often occurs as a result of obesity, high blood pressure and diabetes. For this reason alone, the consumption of these energy-dense, processed foods should be kept to a minimum. However, current data shows that there are other reasons too: UPFs also increase the risk of dementia and Parkinson's disease and can promote depression.

Germans consume a lot of ultra-processed foods

Fast food, ready-made pizza, canned ravioli, instant soup or microwave meals - we all know the benefits: Food is on the table in a matter of minutes, and without any of the "tedious" cooking. The disadvantages, such as high energy density, low vitamin and fiber content, many artificial additives - and the resulting increased health risk of frequent consumption of these products - are little noticed. At least the consumption of UPF is high: with almost 39% of total energy intake coming from highly processed foods (food and drink), Germany ranks high in a European comparison [2]. Business is booming: in 2025, around €6.58 billion is expected to be generated from ready meals alone, and annual sales growth of more than 5% is expected in the following years [3].

The supposedly healthy aspects of the product are advertised, suggesting that it is a healthy food overall. Take ready-made pizza, for example: a 400 g salami pizza contains 857 calories, 28 g fat, 14 g sugar and 5.8 g salt, which incidentally almost covers the recommended daily requirement (97%) [4]. The vegan alternative contains 100 calories less, the same amount of sugar, less salt ("only" 58% of the daily requirement), but 35 g more fat [4]. The bottom line is that there is not much difference. However, it is commendable that the Nutri-Score on both pizzas from this manufacturer provides information and allows consumers to make a quick comparison. "It would be desirable if this nutrient traffic light were mandatory on all packaging," explains Prof. Peter Berlit, Secretary General of the DGN.

Ultra-processed foods and dementia

Various large studies suggest that there is a link between UPF and dementia. Last year, for example, a systematic review based on a meta-analysis [5] showed that high UPF consumption is associated with a 44% higher risk of dementia (of any cause). A recent analysis of the Framingham cohort [6] examined the influence of UPF in the middle years of life (in people under 68 years of age at the start of the survey) on the risk of Alzheimer's disease later in life. It concluded that those who consumed more than 10 servings of processed food per day on average over 12 years had a 2.7-fold increased risk of Alzheimer's disease. The risk increased with the amount consumed: Each serving of ultra-processed food per day was associated, on average, with a 13% increased risk of Alzheimer's after this period.

"Even if these analyses are of high methodological quality, they are only retrospective observational data, which can always be subject to bias. However, it is particularly worrying that last year a first prospective study [7] also showed a link between
highly processed foods and dementia risk," explained Berlit. In the study, every 10% increase in UPF consumption was associated with a 25% increase in dementia risk and a 14% increase in Alzheimer's risk. "In view of this result and the many retrospective studies that point in the same direction, we believe a connection is likely and would like to provide information about it."

How can this connection be explained?

As Prof. Dr. Frank Erbguth, President of the German Brain Foundation, explains, the mechanisms are not fully understood, but various ways in which highly processed food can contribute to dementia are suspected. "On the one hand, there is the indirect link via obesity and the secondary diseases of high blood pressure and diabetes, which are associated with a higher risk of dementia. There is also a mechanism that is thought to be mediated via the intestinal microbiome: Processed foods contain a lot of saturated fats, trans fats, refined carbohydrates, salt and little fiber, which can change the microbial diversity in the gut. We know that these changes can lead to pathogenic changes in the brain via the gut-brain axis." Last but not least, individual substances such as artificial flavors or other additives could also have a direct neurotoxic effect and promote the development of dementia. For example, glutamate, nitrates and, more recently, microplastics are suspected [8] - "but so far there is no evidence of a causal relationship."

Ultra-processed foods - Parkinson's disease and mental disorders

UPFs also appear to have an influence on the risk of Parkinson's disease. A prospective cohort analysis from nine European countries [9] showed, among other things, that Parkinson's-specific mortality was 23% higher with high UPF consumption.

As Prof. Erbguth emphasizes, the study also showed that the risk can be influenced by a change in diet. "Replacing 10 grams of ultra-processed food per day with the same amount of unprocessed food was associated with a lower risk of overall mortality and cause-specific mortality. We ourselves therefore have the opportunity to exert a direct influence here."

Also interesting: A recent paper points to the higher risk of mental disorders, anxiety disorders and depressive disorders due to the consumption of highly processed foods [10]. An Australian survey [11] had previously shown that the consumption of UPF was associated with an 11% increase in the risk of depression.

"Overall, it is clear that we are not doing ourselves any favors with fast food and convenience foods when it comes to brain health. Nutrition is an important building block for brain health, and it is now well documented that we can protect ourselves from many diseases with a diet rich in fresh salads, vegetables and fiber," concludes Prof. Berlit.

Sources
[1] https://www.dge.de/fileadmin/dok/wissenschaft/ernaehrungsberichte/15eb/15-DGE-EB... (S. 9).
[2] Mertens E, Colizzi C, Peñalvo JL. Ultra-processed food consumption in adults across Europe. Eur J Nutr. 2022 Apr;61(3):1521-1539. doi: 10.1007/s00394-021-02733-7. Epub 2021 Dec 3. PMID: 34862518; PMCID: PMC8921104.
[3] https://de.statista.com/outlook/cmo/lebensmittel/convenience-food/fertiggerichte...
[4] https://www.oetker.de/produkte/p/die-ofenfrische-diavolo and
https://www.oetker.de/produkte/p/ristorante-margherita-pomodori-vegan
[5] Henney AE, Gillespie CS, Alam U, Hydes TJ, Mackay CE, Cuthbertson DJ. High intake of ultra-processed food is associated with dementia in adults: a systematic review and meta-analysis of observational studies. J Neurol. 2024 Jan;271(1):198-210. doi: 10.1007/s00415-023-12033-1. Epub 2023 Oct 13. PMID: 37831127; PMCID: PMC10770002.
[6] Weinstein G, Kojis D, Banerjee A, Seshadri S, Walker M, Beiser AS. Ultra-processed food consumption and risk of dementia and Alzheimer's disease: The Framingham Heart Study. J Prev Alzheimers Dis. 2025 Feb;12(2):100042. doi: 10.1016/j.tjpad.2024.100042. Epub 2025 Jan 1. PMID: 39863327; PMCID: PMC12184002.
[7] Li H, Li S, Yang H, Zhang Y, Zhang S, Ma Y, Hou Y, Zhang X, Niu K, Borné Y, Wang Y. Association of Ultraprocessed Food Consumption With Risk of Dementia: A Prospective Cohort Study. Neurology. 2022 Sep 6;99(10):e1056-e1066. doi: 10.1212/WNL.0000000000200871. Epub 2022 Jul 27. PMID: 36219796.
[8] Gecegelen E, Ucdal M, Dogu BB. A novel risk factor for dementia: chronic microplastic exposure. Front Neurol. 2025 May 30;16:1581109. doi: 10.3389/fneur.2025.1581109. PMID: 40520605; PMCID: PMC12162254.
[9] González-Gil EM, Matta M, Morales Berstein F et al. Associations between degree of food processing and all-cause and cause-specific mortality: a multicentre prospective cohort analysis in 9 European countries. Lancet Reg Health Eur. 2025 Jan 8;50:101208. doi: 10.1016/j.lanepe.2024.101208. PMID: 39867840; PMCID: PMC11764076.
[10] Muncke J, Touvier M, Trasande L, Scheringer M. Health impacts of exposure to synthetic chemicals in food. Nat Med. 2025 May;31(5):1431-1443. doi: 10.1038/s41591-025-03697-5. Epub 2025 May 16. PMID: 40379996.
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