More than half the UK diet is now ultra-processed food (UPF), in the US it’s 73% – and the trend is set to continue; a report found that as countries grow richer, they eat more ultra-processed foods (think long ingredients lists of scientific-sounding words, rather than whole, recognisable foods). Meanwhile, according to the World Health Organisation, one in eight people in the world now live with a mental disorder – so is there a link? Kimberley Wilson, UK-based chartered psychologist and author of the upcoming book Unprocessed: How The Food We Eat Is Fuelling Our Mental Health Crisis, believes so. “There isn’t a single study that says the ultra-processed, Western-style diet is good for your mental health. Diets heavy in ultra-processed foods are associated with more depression, worse anxiety and an increased risk of Alzheimer’s disease and dementia,” she says.
Certain nutrients have been shown to improve sleep and reduce stress, depression and anxiety. It makes sense, then, that eating ultra-processed foods, where intense industrial processes strip food of nutrients, raises mental health risks. “Your brain is made out of nutrients,” explains Wilson. “It functions through sending chemical signals, and those chemicals – serotonin, dopamine, citicoline – are made from nutrients. Eating more UPF, by definition, displaces more nutritious foods in our diet.” Professor Adrienne O’Neil, co-director of the Food & Mood Centre in Australia (a country where UPF consumption accounts for 42% of dietary energy), says the negative impact on mental health is down to the “pro-inflammatory properties” of these foods, and the pro-inflammatory diet is associated with an increased risk of depression. Dr Adam Drewnowski, a world-renowned leader in the study of social disparities in diets and health, says it’s a vicious cycle; “diet quality affects mental health, but dietary choices are also affected by mental wellbeing,” he explains, adding that “stress, in particular, can drive food choices in a bad direction.” In other words, we’re caught in a damaging trap.
Surely what we eat, though, is down to us. Not so, says Wilson, who argues “the vast majority of factors that decide what we eat are socially derived.” Consider this: deprived areas in the UK have five times more fast food outlets than affluent ones, and 1.2 million people in the UK live in ‘food deserts’, where affordable fresh food is inaccessible. Then there’s budget: “A healthy diet is three to six times more expensive than an ultra-processed one,” says Wilson. Therefore, eating well is becoming elitist. “What counts most is purchasing power,” says Drewnowski. “Not everyone has the same degree of choice.”
Food companies also spend billions of dollars on advertising each year. Take Brazil, where 91% of food advertisements are for ultra-processed food. This bombardment, according to Wilson, “capitalises on human inbuilt vulnerabilities. [Advertisements] appeal to our evolutionary programming, which says to make the most of every eating opportunity, choose energy-dense foods and get as much value as you can expending as little energy as possible.” And when we succumb and eat them, a chemical reaction follows; “the brain releases a variety of substances, including opioid peptides,” says Drewnowski. These act on the brain in the same way as drugs – tapping into its reward system. In fact, researchers have argued that ultra-processed foods meet the criteria to be labelled as addictive substances. It’s no wonder we’re hooked.
Megan Riddle, a psychiatrist at the Eating Recovery Center in Denver, says that far from being a simple choice, how we eat is “impacted by deep-seated cultural and racial disparities”. She says, “food is intimately intertwined with culture and ethnicity, power and oppression. Historically marginalised groups have increased rates of food insecurity. There’s also increasing awareness of how food was historically – and now – used as a form of oppression.” She points out that, today, what’s commonly labelled ‘unhealthy’ “stigmatises foods of certain ethnic or cultural backgrounds, perpetuating bias”. For Wilson, it borders on victim blaming. “In the UK, the poorest have to spend up to 74% of their disposable income to have a healthy diet, whereas it’s 11% for the wealthiest households. The idea that it’s about personal choice is insulting.”
Consider this sobering statistic from O’Neil; “those living with serious mental illness die 10 to 25 years sooner than those without,” and what we eat has a major impact. Our food systems are driven by politics, power and profit. “Poorer people in England die up to 10 years younger than rich people [in the US, it’s nearly 15 years] and that’s not about personal choice, it’s about where you live, what you can afford and the influence of the environment on your health,” says Wilson. “The global food system needs to change, but a cultural shift won’t come from individuals. We need a shift in policy – and only governments are in a position to do that.”
Unprocessed: How The Food We Eat Is Fuelling Our Mental Health Crisis by Kimberley Wilson will be published by WH Allen on 23 February 2023
Laura Potter is a freelance editor, writer and interviewer whose work has appeared in The Observer Magazine, The Guardian’s Saturday magazine, The Times Magazine, Women’s Health and Men’s Health
