Are ultra-processed foods like savory snacks, frozen meals and soft drinks really bad for your health? A pair of European studies published Wednesday gives fresh evidence that you are better off avoiding them.
The studies, which both appeared in the British Medical Journal (BMJ), followed groups of people over a period of time in France and Spain and found that those who ate more factory-made foods were at greater risk for heart disease and early death respectively.
Two large European studies published by @bmj_latest today link consumption of highly processed (“ultra-processed”) foods with risk of cardiovascular disease and death https://t.co/gabRKdh9x7 and https://t.co/aShSqFfYhr + linked editorial https://t.co/Q2IEiqvXjJ pic.twitter.com/MIzv0dme4q
— BMJ (@bmj_company) May 30, 2019
This is concerning because these foods are becoming a larger part of people’s diets.
“Ultraprocessed foods already make up more than half of the total dietary energy consumed in high-income countries such as USA, Canada and the UK,” senior author of the Spanish study and professor of preventive medicine and public health at the Universidad de Navarra Maira Bes-Rastrollo wrote in an email to CNN. “In the case of Spain, consumption of ultraprocessed food almost tripled between 1990 and 2010.”
So what exactly did the studies find?
The study Bes-Rastrollo participated in followed nearly 20,000 volunteers aged 20 to 91 between 1999 and 2014, asking them detailed questions about the food they ate every two years. It found that those who ate more than four servings a day of highly-processed foods were 62 percent more likely to die early. That risk went up 18 percent for every extra serving of factory-made food they consumed.
Bes-Rastrollo told CNN her study showed results that agreed with other studies in France and the U.S., which, to her, lent “support” to the idea that ultra-processed diets actually cause ill health.
The French study, conducted by the University of Paris, followed more than 105,000 people over five years. It found that, for every 10 percent increase in the amount of ultra-processed foods someone consumed, their risk of heart attack, stroke or other cardiovascular disease rose around 12 percent, according to The Guardian. The difference in outcome between low and high processed diets was not huge — the results indicated there would be 277 cases of heart disease for every 100,000 people who consumed lots of high-processed foods compared to 242 cases for every 100,000 people who did not. But study author Mathilde Touvier told The Guardian there was enough of a difference to justify abstaining from high-processed snacks.
“The public should avoid these foods as much as they can,” she said. “We need to go back to more basic diets.”
What Are Ultra-Processed Foods?
Researchers classified foods according to something called the NOVA classification system, which puts foods in four categories based on how they are made, as CNN explained:
The “unprocessed or minimally processed” food category included fruits, vegetables, legumes, milk, eggs, meats, poultry, fish and seafood, yogurt, grains (white rice and pasta) and natural juice. Salt, sugar, honey, olive oil, butter and lard were listed in the category of “processed ingredients,” while “processed foods” included cheeses, breads, beer, wine, cured traditional ham and bacon. The final category encompassed ultraprocessed foods such as flan, chorizo, sausages, mayonnaise, potato chips, pizza, cookies, chocolates and candies, artificially sweetened beverages and whisky, gin and rum.
The two studies follow other research suggesting that these highly-processed foods are bad for human health. A previous study had linked consuming them to increased cancerrisk, according to a BMJ editorial published alongside Wednesday’s studies.
“These findings add to growing evidence of an association between ultra-processed food and adverse health outcomes that has important implications for dietary advice and food policies,” editorial authors Mark A. Lawrence and Phillip I. Baker wrote. “The dietary advice is relatively straightforward: eat less ultra-processed food and more unprocessed or minimally processed food.”
— The BMJ (@bmj_latest) May 30, 2019
Why these foods are harmful is still a question for further research. A U.S. National Institutes of Health study suggested processed foods might encourage people to eat more. Researchers monitored all the food eaten by volunteers for a month and found that they ate 500 more calories a day when given the ultra-processed items, BBC News reported.
Other possibilities include the fact that these foods lack nutrients and fiber, are easy to eat, are more immediately attractive than healthier options and contain food additives that, while tested for safety individually, may have harmful effects when eaten in combination, BBC News said.
However, some question the “ultra-processed” category. Biochemist and University of Reading Associate Professor of Nutrition and Health Gunter Kuhnle said the studies were “very well and thoroughly conducted,” but thought the NOVA categories were not clear.
“While ‘ultra-processed’ food is commonly assumed to be food that is extensively processed … it actually contains foods which undergo few processing steps, such as hamburgers, crisps or chips, or those that contain preservatives that have been used for centuries such as preserves,” he wrote, as CNN reported. “It is also not obvious why salami is considered to be ultra-processed, yet cheese, which often requires considerably more processing steps and additives, is not.”