5 foods a brain expert says ‘weaken memory and focus’

Harvard nutritionist says she tries to avoid or at least cut back on these foods

What you didn’t know about bacon

As a Harvard-trained psychiatrist, a nutrition specialist and professional chef, Dr. Uma Naidoo knows a thing or three about brain food. After all, she wrote the book “This Is Your Brain on Food” and studies how gut bacteria can trigger metabolic processes and brain inflammation that affect memory.

Studies point to the idea we might be able to reduce the possibility of dementia by avoiding foods that can compromise our gut bacteria and weaken our memory and focus, she wrote for CNBC.

Naidoo wrote that she tries to avoid or cut down on these five things “to fight inflammation and promote brain health, sharp thinking and good decision-making.”

Added sugars

Although the brain needs glucose — a form of sugar — to fuel cellular activities, too much could cause memory impairments and reduce the plasticity of the part of the brain that controls memory, Naidoo wrote.

“Consuming unhealthy processed foods like baked goods and soda, which are often loaded with refined and added sugars — often in the form of high-fructose corn syrup — floods the brain with too much glucose,” she said.

Fried foods

When it comes to brain health, Naidoo wrote, fried foods are a “less is more” dish.

A 2016 Cambridge University study that included 18,080 people found that a diet high in fried foods was linked to lower scores in learning and memory. The likely reason: These guilty pleasures cause inflammation that can damage the blood vessels that supply the brain with blood. Another study that year found that people who consumed more fried foods were more likely to develop depression in their lifetime.

If you eat fried food every day, Naidoo recommends cutting back to once a week. Once a week? Cut back to once a month.

High-GI carbs

Bread and pasta might not be sweet, but your body processes them much the same way it does sugar. A 2018 study in Spain questioned more than 15,000 people to determine which carbs were linked to depression.

Carbohydrates such as whole grains and foods high in fiber were classified “better quality” and were ranked low on the glycemic index, which measures how fast foods convert to glucose during digestion. The quicker the conversion, the higher its GI ranking.

The researchers found that participants who ate more better-quality carbs were 30% less likely to develop depression. Low-GI foods include green veggies, most fruits, carrots, kidney beans, chickpeas and lentils.


Alcohol has a large role in the holidays, including the Fourth of July.

In 2018, Archana Singh-Manoux, a research professor and director at the French Institute of Health and Medical Research, and her colleagues followed 9,087 people over 23 years to see how alcohol related to the incidence of dementia, Naidoo wrote.

They reported in the British Medical Journal that people who drank no alcohol or who consumed more than 14 drinks per week had a higher risk of dementia compared to those who drank alcohol in moderation.


Bacon, sausage and salami contain nitrates, which is used as a preservative and color enhancers in deli slices.

In a March 2020 study, researcher at Johns Hopkins Medical School found nitrates could alter gut bacteria in a way that causes bipolar disorder.

“No matter how old you are, it’s never too late to start eating in a way that gives you the best possible chance of staving off dementia as you age and making sure that you feel focused and sharp every day,” Naidoo concluded.