This Is the Absolute Worst Food for Brain Fog, According to a Registered Dietitian

Want to think more clearly? Avoid this food.

"Fog" isn't just a weather term. It's also used to describe cloudy thinking. And brain fog is something that more and more people are talking about these days—not to mention, trying to avoid.

"Brain fog is not a mental condition," explains Courtney Barth, RDN, LD, a registered dietitian with Cleveland Clinic’s Center for Human Nutrition. "But it has become a popular topic, especially due to long-haul COVID-19 symptoms."

Regardless of the source of brain fog, COVID or otherwise, Barth says it's important to discuss and fight.

"Constantly feeling like you cannot concentrate or be productive can really affect one's mental health, so talking about this can help with overall support," Barth explains. "Brain fog can also interfere with work, school or just everyday life, which can be taxing."

Believe it or not, diet can play a role in brain fog too. Barth has explained why and what food can increase the likelihood you'll experience brain fog.

Related: 6 Habits To Reduce Long COVID Risk

Why Is Diet Important for Brain Fog?

You may be surprised that what you eat can affect how you think. But Barth says that it can, and research from 2021 cites nutrition as a brain fog factor.

"Carbohydrates are our brain’s main fuel source," Barth says. "It is recommended to consume at least 130 grams of carbohydrates a day for optimal brain function, focusing on complex carbohydrates to provide additional vitamins, minerals and fiber."

Barth adds that other nutrients like vitamin B12 (found in animal protein) and omega-3 fatty acids (found in salmon, olive oil and avocado) can also help. Imbalanced blood sugar levels can also be a cause, particularly if brain fog appears as part of your daily "3 p.m. slump."

"Around that 2 to 3 p.m. timeframe, a lot of us start to feel some brain fog or fatigue, which could be due to lower blood sugar levels. Instead of going for the coffee, try a snack that has a high-fiber carbohydrate paired with a protein source," Barth recommends.

Finally, dehydration can affect brain fog.

"Recommendations for fluids should be individualized, but in general, women need about nine cups of fluid per day, and men about 13 cups of fluid per day," Barth says.

Related: What Are the Effects of Long COVID-19?

What Is the Worst Food for Brain Fog?

Heavily processed foods are the worst foods for brain fog, according to Barth. These types of foods include chips, candy, chicken nuggets, hot dogs and fries.

"These foods tend to be higher in saturated fats, sugar and salt," Barth says. "Overall, these foods provide little nutritional benefit, lacking the vital vitamins and minerals to support brain health. They could also cause inflammation, and chronic low-level inflammation can be detrimental to the mind and body."

Limit these foods if brain fog is a problem or if you're hoping to prevent it in the first place.

Related: You'll Want To Add This Spice To Your Pantry ASAP

What Else To Avoid If You're Fighting Brain Fog

Food isn't the only factor in your diet to evaluate. You'll also want to keep an eye on what you are drinking—specifically alcohol.

"Alcohol itself provides no nutritional benefit to the body," Barth says. "Consuming alcohol can limit one's cognitive focus and can increase the risk of dehydration."

Barth refers to the CDC guidelines for alcohol consumption: one drink or fewer per day for women and two drinks or fewer per day for men.

Barth says limiting artificial sweeteners, especially aspartame, may be a good idea as well.

"One study recommended that the usage of aspartame may be responsible for behavioral and cognitive problems, but more studies are needed," Barth points out. "The FDA has stated that artificial sweeteners are safe for consumption, so I believe more studies on amount and frequency of consumption would be beneficial."

What To Do About Brain Fog

First, Barth says to focus on eating nutritious foods.

"Focus on foods to support brain health, such as antioxidant-rich fruits and vegetables, whole grains that are high in fiber to support better blood sugar management, foods high in vitamin B12 such as lean meats, fish and poultry, and foods high omega-3 fats such as salmon, walnuts or olive oil," she says.

Some of her favorite snacks to fight the 3 p.m. slump include string cheese and Greek yogurt with fruit. It's not just about what you eat, though—it's when you eat too.

"Skipping meals can cause fluctuations in blood sugar levels, so it is important to not skip meals," Barth says. "Aim to eat every three to five hours, and always pair your carbohydrate source with some protein and fiber."

It's also important to know the signs of brain fog so you can tweak or get help if needed. "Some signs could include fatigue, inability to concentrate or just feeling fuzzy or cloudy," Barth says.

Finally, take a holistic approach to your life: Focus on overall healthy lifestyle habits such as aiming to get seven to nine hours of sleep at night, limiting screen time before bed, exercising and managing stress levels," Barth says.

Next up: The 11 Best Foods for Your Brain

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