Long-Term Effects Of A Bad Diet On Your Brain

How Diet Affects Your Brain

As with any organ in the body, the brain requires all the essential nutrients to function optimally. A balanced approach to nutrition is necessary for brain health throughout the lifespan but is especially important as we age.

How Does Repeated Consumption of Unhealthy Foods Impact the Brain?

Consuming a nutritious diet is essential for maintaining brain health and is especially important over time due to cumulative interactions between the diet and the brain. An article from the British Medical Journal stated that attention to nutrition long-term could lessen the impact of several brain diseases, such as Parkinson’s disease, Alzheimer’s disease, and other types of dementia. Good nutrition is also beneficial for mental health throughout life.

Unfortunately, the standard American diet, high in sugar, fat, and processed food, adversely affects brain function and mental health. This occurs primarily through perturbation of the microbiome and gut-brain axis. The human microbiome consists of 10¹⁴ bacteria, which is 10 times the number of human cells found in the body. These beneficial and harmful bacteria are acted upon by processed food’s industrialized chemicals and additives, causing them to secrete substances that alter the immune system, affect hormones, and contribute to the overall functioning of the human body, particularly the brain.

The gut microbiome has been implicated in several brain diseases, including:

• Autism
• Anxiety
• Obesity
• Schizophrenia
• Parkinson’s disease
• Alzheimer’s disease

This is due to the interaction between substances produced by the bacteria, the immune system, and the brain.

Fortunately, close attention to a healthy diet can improve brain function and mental health over the lifespan. Focusing on nutrition is the most critical factor in optimizing the microbiome and helping mitigate these adverse effects.

What Are the Worst Foods for Your Brain?

Ultra-processed foods such as cookies, instant noodles, ready-made meals, and sodas consist mainly of chemically modified food substances with additives for taste, texture, appearance, and shelf-life. They contain minimal to no whole foods and have increased in the Western diet over the past several decades. Their ingredients cause inflammation, which is the underlying cause of many chronic diseases.

Evidence strongly suggests that this long-term dieting pattern increases all-cause mortality, which means it could shorten your life. Several components of the standard American diet are especially harmful to brain health, including added sugar (and sugar substitutes), refined carbohydrates, and trans fat.

Sugary Drinks

Sugar and sugary drinks have several adverse effects on the brain. Sugar appears to decrease the concentration of a crucial brain chemical called brain-derived neurotrophic factor. This compound plays a vital role in the function of brain cells, including memory, learning, mood, and cognitive function.

Fructose, a sugar commonly found in sugary drinks, affects brain health by causing inflammation and insulin resistance. Sodium benzoate, a compound found in soda, can impair memory, cause incoordination, and worsen symptoms of attention-deficit/hyperactivity disorder.

Sugar-sweetened beverages can also worsen sleep and increase the risk of stroke and dementia. Simple sugars and sugar substitutes should be avoided in sugary drinks and used in moderation in other foods.

Refined Carbs

Refined carbohydrates are found in white bread, pasta, flour, and many processed foods. A 2020 study in the journal Clinical Nutrition discovered that when consumed over a prolonged period, these carbohydrates have been associated with a decline in cognitive function, particularly in older individuals. In contrast, whole grains and foods high in fiber benefit the human microbiome and brain, improving cognitive function.

Simple, processed carbohydrates are also associated with disruptions in sleep due to insulin spikes. Refined carbohydrates can also worsen mental health disorders such as depression, anxiety, panic disorders, and autism.

Trans Fats

Trans fats are artificial substances prevalent in processed food and absent in whole, natural food. Examples of food with trans fat include:

• Commercially baked goods
• Shortening
• Microwave popcorn
• Fried foods
• Nondairy creamer
• Frozen pizza
• Refrigerated dough

A diet high in these substances and saturated fat can decrease brain health and functioning. This is likely due to the inflammation caused by these substances and the stress on the brain from high amounts of sugar, a common ingredient in several types of processed food. Avoiding ultra-processed food and checking labels for trans fat can help you optimize your brain health.

Excess Alcohol

Recommended daily limits for alcohol are no more than one drink daily for women and no more than two drinks for men. Excessive consumption can cause a deterioration in both mental health and brain performance over time. This is likely due to the toxic effect of alcohol on brain cells, soavoiding alcohol can contribute to a brain-heathy diet.

How Much Unhealthy Food Is Too Much?

Indulging in “unhealthy” food occasionally will not negatively affect your brain, and it is part of eating in a balanced way. You want to allow yourself occasional treats, participate in holiday traditions, and allow yourself some wiggle room not to be overly restrictive.

A general rule of thumb is to stick to a healthy diet 80–90% of the time and allow yourself to eat without strict limitations the rest of the time. For example, you can reserve a meal or two on the weekend during which you will allow yourself to eat processed or sugary food, or you can participate in family traditions on holidays. This will give your brain the nutrients it needs and minimize the adverse effects of a bad diet.

What Foods Are Good for Your Brain?

Diets rich in antioxidants and anti-inflammatory compounds, such as fruits, nuts, vegetables, and fish, are linked to a reduced risk of cognitive decline with age and a decreased risk of developing several brain diseases. Several studies show that a long-term adherence to the Mediterranean diet (containing plentiful fruits, vegetables, whole grains, and olive oil) can improve cognitive function later in life.

The Mediterranean diet has been shown to increase the number of good bacteria in the body, reduce inflammation, and aid the production of neurotransmitters. This is due to the high polyphenol concentration in many fruits and vegetables. This dietary pattern has been shown to have a long-term effect on the brain through improved cognition, ability to reason, and processing speed in midlife and later.

A few good brain foods deserve special mention:

• Nuts have been shown to increase cognitive performance due to their anti-inflammatory properties and mitigating effects on dementia. A small handful per day has shown the most benefit.
• Olive oil contains oleic acid, which is antioxidant, anti-inflammatory, and neuroprotective. Increased consumption of this chemical is associated with better brain health. You can use olive oil to cook your food or to make salad dressing.
• Fish can decrease the risk of dementia and is associated with enhanced brain performance in adulthood.This is thought to be due to the levels of anti-inflammatory omega-3 polyunsaturated fatty acids. These substances make up the membranes of brain cells and assist in transmitting signals between cells. Try to eat fish two times per week.
• Dark chocolate contains cocoa flavonoids, which can improve brain health and function through antioxidant and anti-inflammatory properties. Look for 70% dark chocolate and limit it to two ounces to avoid consuming too much sugar.
• Green tea, from the plant Camellia sinensis, can also improve brain health and cognitive performance through its anti-inflammatory, antioxidant, and stimulant properties.

Incorporating these foods with brain-positive nutrients can positively impact your brain health in the short and long term.

How to Change Your Diet

The simplest way to modify your diet for brain health is to avoid ultra-processed food and incorporate more whole foods such as fruits, vegetables, whole grains, and fish. Ultra-processed foods contain sugar, trans fat, and several chemicals that are linked to long-term adverse health consequences and mental health issues. The NOVA food classification system can help differentiate whole from processed food using different levels:

• NOVA 1: Unprocessed or whole foods, such as the edible parts of plants or animals straight from nature.
• NOVA 2: Culinary ingredients, such as salt, oil, sugar, or starch.
• NOVA 3: Processed foods like baked bread, canned vegetables, or cured meats.
• NOVA 4: Ultra-processed food requires no preparation and is industrially formulated from substances derived from foods, chemicals, and additives.

Avoiding NOVA 4 foods and incorporating whole foods will improve your diet and brain health.

Another easy way to change your diet is to use the plate method. Fill half of your plate with fruits and vegetables with every meal. Reserve one-quarter of your plate for lean proteins, with a focus on fish or plant sources such as beans or soy. The remaining quarter of your plate should contain whole grains. You should be able to recognize the grain (brown rice, quinoa, bulgar, oatmeal). Try to avoid refined grains such as white flour or white rice. Fats can be used sparingly, focusing on healthy fats such as olive oil or avocado. This method will fill your meal with high-quality, brain-healthy food that can feed your microbiome.

The Final Verdict: Good Nutrition Equals Better Brain Function

An ultra-processed diet high in fat, sugar, and chemical ingredients has a deleterious effect on brain health, especially if consumed throughout a lifetime. In contrast, adding wholesome, nutritious food that decreases inflammation and nourishes the gut-brain axis can improve mental health and cognitive performance.

Start by making small, manageable changes today, so you can reap the many benefits of a brain-healthy diet for years to come.