Eating ultraprocessed foods for more than 20% of your daily calorie intake every day could set you on the road to cognitive decline, a new study revealed.
We all know eating ultraprocessed foods that make our lives easier -- such as prepackaged soups, sauces, frozen pizza and ready-to-eat meals -- isn't good for our health. Nor is gobbling up all the pleasure foods that we love so much: hot dogs, sausages, burgers, french fries, sodas, cookies, cakes, candies, doughnuts and ice cream, to name just a few.
Studies have found they can raise our risk of obesity, heart and circulation problems, diabetes and cancer. They may even shorten our lives.
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Now, a new study has revealed eating more ultraprocessed foods may contribute to overall cognitive decline, including the areas of the brain involved in executive functioning -- the ability to process information and make decisions.
In fact, men and women who ate the most ultraprocessed foods had a 28% faster rate of global cognitive decline and a 25% faster rate of executive function decline compared with people who ate the least amount of overly processed food, the study found.
"While in need of further study and replication, the new results are quite compelling and emphasize the critical role for proper nutrition in preserving and promoting brain health and reducing risk for brain diseases as we get older," said Rudy Tanzi, professor of neurology at Harvard Medical School and director of the genetics and aging research unit at Massachusetts General Hospital in Boston. He was not involved in the study.
Tanzi, who has written about ultraprocessed foods in his book "The Healing Self: A Revolutionary New Plan to Supercharge Your Immunity and Stay Well for Life," said the key problem with ultraprocessed foods is that "they are usually very high in sugar, salt and fat, all of which promote systemic inflammation, perhaps the most major threat to healthy aging in the body and brain.
"Meanwhile, since they are convenient as a quick meal, they also replace eating food that is high in plant fiber that is important for maintaining the health and balance of the trillions of bacteria in your gut microbiome," he added, "which is particularly important for brain health and reducing risk of age-related brain diseases like Alzheimer's disease."
It's not a lot of calories
The study, presented Monday at the 2022 Alzheimer's Association International Conference in San Diego, followed over 10,000 Brazilians for up to 10 years. Just over half of the study participants were women, White or college educated, while the average age was 51.
Cognitive testing, which included immediate and delayed word recall, word recognition and verbal fluency were performed at the beginning and end of the study, and participants were asked about their diet.
"In Brazil, ultraprocessed foods make up 25% to 30% of total calorie intake. We have McDonald's, Burger King and we eat a lot of chocolate and white bread. It's not very different, unfortunately, from many other Western countries," said coauthor Dr. Claudia Suemoto, an assistant professor in the division of geriatrics at the University of São Paulo Medical School.
"Fifty-eight percent of the calories consumed by United States citizens, 56.8% of the calories consumed by British citizens, and 48% of the calories consumed by Canadians come from ultraprocessed foods," Suemoto said.
Ultraprocessed foods are defined as "industrial formulations of food substances (oils, fats, sugars, starch, and protein isolates) that contain little or no whole foods and typically include flavorings, colorings, emulsifiers, and other cosmetic additives," according to the study.
"People who consumed more than 20% of daily calories from processed foods had a 28% faster decline in global cognition and a 25% faster decline in executive functioning compared to people who ate less than 20%," said study coauthor Natalia Gonçalves, a researcher in the department of pathology at the University of São Paulo Medical School.
For a person who eats 2,000 calories a day, 20% would equal 400 or more calories -- for comparison, a small order of fries and regular cheeseburger from McDonalds contains a total of 530 calories.
Those in the study who ate the most ultraprocessed foods were "more likely to be younger, women, White, had higher education and income, and were more likely to have never smoked, and less likely to be current alcohol consumers," the study found.
"People need to know they should cook more and prepare their own food from scratch. I know. We say we don't have time but it really doesn't take that much time," Suemoto said.
"And it's worth it because you're going to protect your heart and guard your brain from dementia or Alzheimer's disease," she added. "That's the take-home message: Stop buying things that are superprocessed."
How processed foods cause weight gain
How processed foods cause weight gain
Both nutrition scientists and the public debate the relative merits of so-called healthy diets, such as vegan, paleo, and low-carb, but most experts agree on one thing: avoid ultra-processed foods and stick to a diet of whole, unprocessed foods. Ultra-processed foods contain high-fructose corn syrup, hydrogenated oils, and artificial flavors that make them high in salt, sugar, and fat. They are also lower in protein, fiber, and important nutrients than unprocessed foods.
Ultra-processed foods are formulated to be soft and chewy. These appealing textures make them highly palatable and easy to swallow, so people are likely to eat more ultra-processed foods than unprocessed foods in a shorter amount of time.
A diet high in ultra-processed foods has also been associated with an increased risk of depression, which can lead to weight gain due to eating more or little physical activity or immunometabolic dysregulation. While consuming too many processed foods greatly contributes to weight gain, it may not be the only reason for someone’s body weight: Gastrointestinal complications and other health conditions—some that are even genetic—can be a leading cause of obesity. Understanding the cause of someone’s weight is a crucial first step, and cutting back on processed foods can also help the weight-change process.
Perfect Keto reviewed scientific studies from the National Institutes of Health (NIH) and other institutions and health reporting from Medical News Today and Live Science to compile this list of six ways ultra-processed foods can lead to weight gain.
Ultra-processed foods trigger ‘hunger’ hormones
A study from the National Institutes of Health tested 10 men and 10 women and found that levels of the appetite-stimulating hormone ghrelin increased during the two weeks they ate a diet of ultra-processed foods compared to baseline. Levels of the appetite-suppressing hormone pancreatic peptide YY (PYY) increased during two weeks on a diet of unprocessed foods. After two weeks, participants who received the ultra-processed diet first received the unprocessed diet, while those who received the unprocessed diet received the ultra-processed diet. PYY increased in participants when they received the unprocessed diet and ghrelin increased in those switched to the ultra-processed diet.
Ultra-processed foods contain significant amounts of refined carbs, sugar, and fat
The ultra-processed foods given to participants in the NIH study differed from the unprocessed foods in the proportion of added sugar to total sugar content (~54% versus 1%, respectively), insoluble to total fiber ( ~16% versus 77%), and saturated to total fat (~34% versus 19%). Those who ate the ultra-processed diet ate about 508 calories more per day than those eating the unprocessed diet. Kevin Hall, lead author of the study, told Medical News Today that the researchers hypothesized eating ultra-processed foods would lead to a higher caloric intake because they are high in sugars, salt, and fat, and low in fiber.
Ultra-processed foods are consumed more quickly
Participants in the NIH study ate an extra 17 calories (7.4 grams of food) per minute when they ate ultra-processed foods versus unprocessed foods. The researchers said the additives in ultra-processed foods, such as industrial oils and synthetic preservatives, make them softer and easier to chew and swallow. This may have led participants to eat a greater quantity of food at a more rapid rate. Furthermore, eating too quickly may also lead to developing a gastrointestinal disorder such as gastritis, but the link between eating fast and health disorders is still unclear. Gastritis causes inflammation that erodes the stomach lining, potentially leading to ulcers.
Additives in ultra-processed foods cause inflammation in the gut
When researchers fed healthy mice polysorbate-80 and carboxymethylcellulose, two emulsifiers often found in ultra-processed foods, the mice ate more and gained weight. They developed metabolic syndrome and had trouble regulating their blood sugar. When the researchers examined the animals’ gut tissue under a microscope, they saw signs of mild inflammation. The emulsifiers promoted the growth of harmful bacteria in the gut that can digest the mucus lining in the gut or grow closer to the intestinal tissue itself.
The study findings added to a growing body of evidence that bacteria that live in the human body, including the gut microbiome, play an important role in overall health. However, it is worth noting that although eating plenty of ultra-processed foods can cause significant weight gain, so can gastrointestinal disorders such as gastroesophageal reflux (or GERD), ulcers, and Crohn’s disease.
Ultra-processed foods are linked to depression
Researchers from Spain and Brazil found that, among almost 15,000 adults in Spain, 774 developed depression during the study follow-up period of about 10 years. Those who ate ultra-processed foods most often had a 33% higher risk of depression than those who ate ultra-processed foods the least often. The risk of depression was greater among those who reported low levels of physical activity. In a 2018 study, participants with depression who also had increased appetite had significant immunometabolic dysregulation, including insulin resistance, which is associated with weight gain.
This story originally appeared on Perfect Keto and was produced and distributed in partnership with Stacker Studio.
