FoodProcessed Foods

Processed Foods Proven to Reduce Brain Function


A new study confirms:

Eating processed foods is closely associated with lowered cognitive decline.

Researchers published their findings in the JAMA Neurology.

The study participants were over ten thousand ethnically diverse Brazilians ranging in age from 34 to 74. They’re part of the Brazilian Longitudinal Study of Adult Health.

That’s a major research project led by Natalia Gomes Gonçalves of the Department of Pathology at the University of São Paulo Medical School in São Paulo, Brazil.


The study lasted years. They used 12 months to establish a baseline of the eating habits of the subjects. Then they tested the subjects’ cognitive functioning three times every four years – for a total median follow-up period of eight years.

Therefore, this is a serious study because it did look at the long-term results of eating processed foods. People who ate very small or very large amounts of food were excluded. So were subjects taking medications that could affect their cognitive functioning.

The mean age was 51.6 years old. Around 54% were women.


Researchers categorized the foods the subjects ate into three groups, based on just how processed they were.

Group One: This was unprocessed or minimally processed foods.

Group Two: Canned fruits, artisanal bread and cheese and meat and fish that had been salted, smoked or cured.

Group Three: Highly processed foods. This consists of pretty much everything else. A lot of it contains preservatives, emulsifiers, flavors, sweeteners and other ingredients designed to makes them irresistible to consumers by hiding the naturally unpleasant taste of these foods.

Around 58% of calories in the average American diet consists of ultra-processed foods, which is no surprise. The British are just behind us, at 57%. 48% of calories consumed in Canada come from ultra-processed foods. And 30% in Brazil.


The Results

Subjects who obtained more than 19.9% of their calories from processed foods demonstrated a global cognitive decline 28% faster than those who consumed less than 19.9% of their calories from processed foods.

And in executive function – critical daily skills of living – the over 19.9% of processed food eaters displayed a 25% faster decline than those who ate below that 19.9%.

Researchers tested their memories: immediate recall, later recall and recognition word lists.


Association is Not Causation

However, it’s hard to believe what you eat doesn’t affect your brain’s functioning – for good or ill. Maybe the study participants who ate less processed food were also more likely to exercise, get healthy amounts of sleep and otherwise take care of their personal health better than people who don’t care what they eat.

The association is not causation, but it’s not hard to find logical reasons why processed foods affect your total health, youthfulness, longevity, and brain function.


Reasons Processed Foods Rob You of Your Brainpower

1. Minimal nutrients

We know we eat for vitamins and minerals. Many of us know we also need phytonutrients and antioxidants.

Processed foods contain very little of their original nutrients. The act of processing separates wheat germ out of flour so it’s white, pulverizes soybeans so their isolate can be shaped into whatever and removes healthy skins from potatoes – and that’s just the beginning.

Modern food is “manufactured,” not grown. They do add back maybe 1% of the vitamins they process out of the food, then tell us it’s “enriched.”


2. Minimal fiber

Food processing strips out pretty much all fiber. But that’s the food your healthful microbes in your gut biome need to flourish. 

Your brain and your intestines are closely linked, especially by the vagus nerve. Also, your microbiome generates so many neurotransmitters it’s considered your second brain.

We need plenty of fiber to grow healthy gut bacteria. Unhealthy gut bacteria make us more vulnerable to brain problems, including autism, Alzheimer’s and Parkinson’s. 


3. Surges in blood sugar and insulin

Your body needs sugar circulating in your blood so your cells can burn it for energy. But not too much. Too much sugar in our blood is destructive.

Similarly, you need insulin, but not too much. Yet insulin spikes along with blood sugar.

Processed foods have been robbed of their fiber and nutrients, so there’s nothing to slow down digestion.

As a result, processed foods practically jump from your stomach into your blood stream – unlike whole foods, which have to be slowly digested.


 4. Excess salt

Food processors love to add salt to foods. It drives consumers to eat foods that would otherwise taste digusting. Salt binds with water, so it’s a cheap and easy way to make some foods, such as meat, weigh more than they really do.

But excess sodium over intake of potassium is a strong driver of high blood pressure.


5. Excess fake ingredients

Just read the list of ingredients on the box. How many do you know? How many do you understand what their effect on your long-term health may be? You don’t – probably nobody does. We’re all guinea pigs.

How many of the ingredients are known to anybody except the food scientists that spend their careers “inventing” new foods in laboratories?


6. Excess bad fats

If the food “manufacturer” doesn’t expect you to eat a food because it’s salty, they’ll add plenty of fat to it.

However, high intake of trans fatty acids, saturated fats and Omega-6s breaks down the plasticity of brain cells. This reduces the ability of those brain cells to process information.


7. Excess sugar

And if the manufacturer of some processed food isn’t appealing to your hardwired taste for salt or fat, they’re appealing to the last basic craving: sweetness.

Therefore, many processed foods contain way too much sugar. That includes regular table sugar, highly processed corn syrup and fructose. 

Processed means the sweetness has been removed from being an intrinsic part of a natural food.



Getting at least 20% of your calories from processed foods increases your risk of cognitive decline and executive function.

However, don’t take that as permission to eat up to 19.9% of processed calories.

Given the strength of the association, you’re likely to remain healthier and smarter if you keep consumption of ultra-processed foods as low as possible.