Think that bag of crisps or your daily sweet treat is harmless? Think again. Scientists are now warning that regularly eating ultra-processed foods (UPFs)—think ready meals, ice cream, ketchup, and anything loaded with additives, preservatives, or emulsifiers—might be physically changing your brain, making you crave more and setting up a vicious cycle of overeating.
A new international study, published in Nature, analysed brain scans from over 33,000 UK adults and found striking changes in areas that control hunger and reward. People who ate more UPFs showed altered brain structures linked to food addiction, poor self-control, and even early signs of cognitive decline.
Professor Arsène Kanyamibwa, co-author of the study, explained, “These brain changes are not just about obesity or inflammation—they appear to be directly linked to the ingredients in ultra-processed foods, like emulsifiers.” Essentially, your favourite snacks may be messing with how your brain signals fullness and reward, making it harder to stop eating even when you’re full.
The study followed participants over eight years, looking at their diets and metabolic health. On average, nearly half of the calories consumed came from ultra-processed foods—well above recommended levels. The research showed that higher UPF intake was linked to inflammation in the hypothalamus (which regulates hunger) and reduced cell density in the brain’s reward centres, like the nucleus accumbens. These changes can weaken self-control and intensify cravings.
In plain terms: your junk food habit may literally be rewiring your brain, pushing you toward more unhealthy eating and increasing risks of type 2 diabetes, heart disease, high blood pressure, and even early cognitive decline.
And it’s not just theoretical. Earlier research found that eating an extra 100g of UPFs per day—roughly two packets of crisps—was linked to a nearly 6% higher risk of heart problems and a 14.5% higher risk of high blood pressure.
Experts warn that cutting back on UPFs and focusing on whole foods, balanced diets, exercise, and proper sleep can help protect your brain—and your body. Because it’s not just your waistline at stake; it’s your mind too.
