6 Worst Foods for Your Brain Health (and What to Eat Instead)

Ever feel like your brain is trapped in a fog—forgetting simple things, having trouble focusing, or feeling mentally exhausted by midday? It’s easy to blame stress, poor sleep, or the natural effects of aging. But more often, the real cause isn’t just your hectic lifestyle—it’s the foods you consume and the overall quality of your diet.

Your brain may only account for about 2% of your body weight, but it consumes over 20% of your energy. That energy comes directly from the foods you eat, which means your diet greatly influences how well your brain functions. The type of fuel you select doesn’t just affect performance—it can either improve mood, focus, and clarity or have the opposite effect by damaging neurons, interfering with neurotransmitters, and accelerating cognitive decline.

Let’s take a closer look at the six worst foods for your brain—and explore how simple upgrades to your plate can sharpen your mind.

1. Sugary Drinks

From sodas to sweetened coffees, energy drinks, and even “natural” fruit juices, sugary beverages pose one of the biggest threats to brain function—especially when consumed regularly.

Why it’s bad for your brain:

Excessive sugar intake causes chronic inflammation and oxidative stress in brain tissue.

High sugar diets can lead to insulin resistance in the brain, impairing memory and learning.

A 2017 study in Alzheimer’s & Dementia found a strong link between sugary drink consumption and reduced total brain volume and poorer episodic memory.

Fructose, a common sweetener in sodas, has been shown to interfere with the hippocampus, a brain region critical for forming new memories.

Better option:

Hydrate with filtered water, unsweetened herbal teas, or green tea (which contains L-theanine and EGCG, compounds known to support cognitive performance).

2. Refined Carbohydrates

Refined carbs include white bread, pastries, crackers, white rice, and most boxed breakfast cereals. These foods are stripped of fiber, vitamins, and minerals, causing quick spikes in blood sugar. 

Why it’s bad for your brain:

These carbs break down quickly into glucose, overloading your system and causing post-meal crashes. ‘I feel amazing,’ said no one after eating a sugar-coated, cream-filled donut.

High-glycemic-load meals have been shown to impair memory in both children and older adults.

A 2015 longitudinal study of over 800 older adults in Sweden found that individuals with higher dietary glycemic load experienced faster cognitive decline.

Better option:

Opt for complex carbohydrates with fiber and slow-release glucose, like:

• Steel-cut oats
• Sweet potatoes
• Quinoa
• Lentils

These help maintain steady blood sugar and support neurotransmitter stability.

3. Trans Fats

By now, most people have heard that trans fats are bad for us—but what exactly are they, and where do they hide? While many countries have banned their use, the U.S. has not fully eliminated them, and they still slip into foods under labels like ‘partially hydrogenated oils.’ Trans fats are industrially produced fats commonly found in margarine, baked goods, fried foods, and processed snacks.

Why it’s bad for your brain:

A 2019 study published in Neurology found that people with higher blood levels of elaidic acid (a trans fat) had up to a 75% increased risk of developing dementia.

Trans fats promote systemic inflammation and damage the structure of neurons, reducing brain plasticity.

They also contribute to atherosclerosis, reducing blood flow to the brain, which is essential for cognitive function.

Better option:

Incorporate brain-healthy fats:

• Omega-3 fatty acids (from salmon, walnuts, flaxseeds)
• Monounsaturated fats (from olive oil, avocado)

These support myelin sheath integrity and neurotransmitter synthesis.

4. Highly Processed Foods

If you can’t pronounce the ingredients — and they sound more like something you’d find on a cleaning product than on a nutrition label — chances are they aren’t good for your body or brain. Highly processed or ultra-processed foods include frozen dinners, chips, sweet cereals, packaged baked goods, and most fast food items. They are often high in calories but low in nutrients.

Why it’s bad for your brain:

These foods are high in refined oils, preservatives, and additives, which can disrupt gut health—and by extension, brain health (via the gut-brain axis).

A 2022 study published in JAMA Neurology found that people who consumed more than 20% of their daily calories from ultra-processed foods had a 28% faster rate of cognitive decline.

Processed foods also contain acrylamide, a neurotoxic compound formed during high-heat cooking.

Better option:

Prepare meals at home using whole, unprocessed ingredients.

Eat a Mediterranean-style diet, which is rich in polyphenols, fiber, and healthy fats shown to protect cognitive health.

5. Artificial Sweeteners (Especially Aspartame)

Artificial sweeteners are found in diet sodas, sugar-free gum, low-calorie snacks, and many “health” products. Aspartame is one of the most widely used but also the most controversial.

Why it’s bad for your brain:

Aspartame is metabolized into phenylalanine, which can cross the blood-brain barrier and disrupt neurotransmitter balance (including dopamine and serotonin).

Animal studies have linked chronic aspartame consumption with learning deficits and emotional instability.

Some human studies suggest a connection between aspartame and mood disorders and slower reaction times.

Better option:

Choose natural sweeteners like stevia, monk fruit, or small amounts of raw honey.

Better yet, retrain your palate to reduce sweetness cravings overall by emphasizing whole foods.

6. Alcohol

Some argue that moderate alcohol intake—especially red wine—may offer certain cardiovascular benefits. However, I believe the harms of any amount of alcohol outweigh the potential upsides. Excessive or chronic use is unequivocally damaging to the brain—not to mention the gut, liver, skin, and more.

Why it’s bad for your brain:

Alcohol affects the hippocampus, impairing memory formation and retention.

Chronic alcohol use is associated with thiamine deficiency (Vitamin B1), which can lead to Wernicke-Korsakoff syndrome—a severe neurological disorder that, if untreated, can progress to irreversible psychosis.

A 2018 study in The BMJ showed that even moderate drinking (7–14 drinks/week) was linked to atrophy of the brain.

It disrupts REM sleep, further reducing the brain’s ability to consolidate memories, impair learning, destabilize mood, and clear neurotoxic by-products

Better option:

Limit alcohol to no more than one drink per day, or better yet, swap it for refreshing alternatives—like sparkling water with herbs and citrus, adaptogenic drinks (such as reishi or ashwagandha blends), or simply filtered water with added electrolytes to stay hydrated, especially if you’re keeping active (as you should!)

So What Should You Eat for Brain Health?

The key to protecting your brain isn’t just cutting out unhealthy foods—it’s replacing them with nutrient-rich options while keeping calories in check. A simple guideline: if it grows from the ground and you can find it at a local farmers market, it’s probably a smart choice. Aim for variety, too—diverse foods support a healthier gut and, in turn, a happier brain.

Top brain-boosting foods:

• Leafy greens – High in folate and antioxidants (spinach, kale, arugula)
• Berries – Packed with flavonoids that improve memory and delay brain aging
• Nuts and seeds – Provide vitamin E and healthy fats
• Fatty fish – Rich in DHA, a critical omega-3 for brain cell membranes
• Olive oil – High in monounsaturated fats and polyphenols
• Fermented foods – Like kimchi, yogurt, and sauerkraut, to improve gut-brain signaling

Upgrade Your Brain, One Bite at a Time

Your brain is your most important asset and requires clean, high-quality fuel to operate optimally. By avoiding or minimizing these six worst foods and substituting them with brain-friendly choices, you can start feeling better today. Want additional tips to boost your brain? Subscribe to the Newy newsletter to receive insights on health, nutrition, and science-backed lifestyle strategies.

 

About the Author:

Dr. Ray Rivas is a medical doctor, former trauma surgeon, and the founder of Innerbloom Ketamine Therapy, a clinic dedicated to advancing mental health care through innovative treatments. With a deep passion for holistic wellness, he also leads Newy, a nootropic supplement company designed to support brain health. Drawing on decades of clinical expertise, a career focused on mental health, and personal experiences with growth and healing, Dr. Rivas is devoted to empowering individuals with the tools they need to achieve lasting mental and physical health.

Disclaimer:

The content provided on this blog and website is for educational and informational purposes only and should not be considered medical advice. Newy supplements are not intended to diagnose, treat, cure, or prevent any disease. Always consult a qualified healthcare professional before starting any new supplement, especially if you are pregnant, nursing, have a medical condition, or are taking other medications.

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