How Diet Impacts Stress and Anxiety

Why Eating a Healthy Diet Is Difficult When You’re Stressed

A person’s diet can directly affect their mental health, including their levels of stress. Studies on stress show that a poor diet is one of the determining factors of higher anxiety levels, with stress affecting several body mechanisms and responses, including:

• Inflammation
• Nutrient deficiencies
• Blood sugar fluctuations
• Chemical mediators
• Stimulant effects
• Bacteria in the gut

Addressing stress is important because it can contribute to other diseases, such as heart disease, strokes, autoimmune conditions, and mental health conditions. However, during times of stress, most people naturally gravitate toward high-fat and high-sugar food for comfort. This is adaptive because the body needs quick energy to escape a stressful situation. However, suffering from chronic stress can result in a constant attack on the nervous system. A healthy diet can help to reverse these effects and create more resiliency in ongoing stressful situations.

Foods That Reduce Stress

Several foods can improve brain function and help reduce stress through their effects on the nervous system. They also decrease inflammation, an underlying mechanism of several mental disorders.

Nuts Improve Heart Rate Variability

Mental stress can affect the heart through stress hormones and directly through the nervous system. One measure of nervous system dysregulation is heart rate variability or the time from one heartbeat to another. Stressed people have lower heart rate variability, reflecting a more dysregulated nervous system. Improved heart rate variability can reflect a more resilient nervous system in the face of stressors.

Lifestyle factors such as diet and exercise can improve the heart rate variability and the stress response. A study published in the journal Nutrients demonstrated that nuts, rich in anti-inflammatory omega-3 fatty acids, can improve heart rate variability and the body’s response to stress.

Snacking on nuts daily may increase resilience to mental stressors.

Probiotics and Fermented Foods

Supplementation with the bacteria Lactobacillus and Bifidobacterium is associated with decreased anxiety and stress symptoms. This is most likely due to the interaction between the microbiome (or bacteria in the gut) and the brain. These bacteria interact through direct chemical signals and indirectly through the immune system.

Beneficial bacteria are found in yogurt or other fermented foods such as sauerkraut, pickles, kombucha, kimchi, and tempeh.

Fatty Fish: Potent Inhibitor of Inflammation

Fatty fish, such as salmon, are rich in omega-3 fatty acids. These polyunsaturated, or “good,” fats decrease inflammation in the brain and improve anxiety. Reduced inflammation in the body increases resiliency to physical and mental stress. Aim for two servings of fatty fish per week.

Fiber: Food for the Microbiome

A 2023 study in Nutrients described a relationship between fiber and mental health. People with mental illnesses have lower levels of stress as more fiber is introduced into the diet. This is because fiber is good food for a healthy microbiome. Vegetables and fruit are good sources of fiber and have many nutrients that decrease stress and anxiety. The most commonly studied fruits and vegetables for this purpose include citrus, grapes, berries, pomegranates, fennel, and lettuce.

Fill half your plate with fruits and vegetables at every meal and incorporate them as snacks.

Meat and Dairy: A Good Source of Vitamin B12

Fluctuating blood sugar levels and crashes can contribute to anxiety symptoms. Fortunately,  protein helps to regulate blood sugar levels. A higher intake of protein and a lower intake of carbohydrates can improve anxiety symptoms.

Meat is also an essential source of vitamin B12. A  study published in the journal Advanced Nutrition found that low levels of vitamin B12 can contribute to lower heart rate variability and lower stress resistance. The best sources of vitamin B12 are milk, eggs, yogurt, salmon, tuna, beef, and clams.

Foods That Increase Stress

The chemicals found in processed food and artificial sweeteners are associated with increased anxiety levels. Alcohol and caffeine also contribute to heightened anxiety despite their depictions in popular culture.

Ultra-Processed Food

Processed food contains food additives, unhealthy fats (such as trans fat), high amounts of sugar, and few vitamins or minerals. These substances contribute to several health problems, including anxiety. For example, the food additive monosodium glutamate (MSG) is associated with increased levels of anxiety. This anxiety makes it more challenging to cope with daily stress.

Examples of ultra-processed food include:

• Packaged cookies
• Potato chips
• Soft drinks
• Breakfast cereals
• Processed meat

Refined Carbs

A 2021 review found that as simple carbohydrates increased in the diet, anxiety levels increased as well. Reducing the amount of carbohydrates in the diet, particularly simple carbohydrates like sugar and white flour, can decrease stress and anxiety.

Sugar and Artificial Sweeteners

Food that is high in sugar can upset the balance of beneficial bacteria in the gut, and large swings in blood sugar can also lead to cravings and anxiety. A review published in the journal Nutrients stated that increased consumption of sugary sweetened beverages can increase anxiety. Artificially sweetened beverages appear to make anxiety worse as well.

Alcohol

Although alcohol is used by many to relieve anxiety and stress, it can often make it worse. As increasing amounts of alcohol are consumed, the brain produces a compound called glutamate to counteract it. Glutamate is anxiety-provoking and stimulating. As the alcohol wears off, the glutamate is still present, resulting in feelings of anxiety and dread.

Alcohol and anxiety disorders are often linked, so avoiding alcohol will lead to lower levels of stress.

Caffeine

Caffeine is a stimulant that can increase anxiety and stress. Higher levels of intake are especially harmful, so it is wise to limit the number of caffeinated beverages consumed per day to one or two. Green tea, however, contains small amounts of caffeine and other beneficial compounds, such as epigallocatechin-3-gallate and l-theanine, which are helpful for anxiety and inflammation.

Swapping out morning coffee for green tea may alleviate anxiety.

What Foods Negatively Affect Mental Well-Being?

Foods that negatively affect mental well-being are usually overly processed and full of fat and sugar. The highly processed standard American diet is associated with decreased mental well-being, depression, and anxiety. These symptoms are likely due to the alteration of the microbiome.

What Foods Can Improve Mental Well-Being?

The Mediterranean diet is one of the most studied diets for anxiety. This diet emphasizes whole grains, fruits and vegetables, anti-inflammatory foods and spices, seafood, legumes, and low amounts of sugar.

A breakdown of the diet reveals why it is so beneficial:

• Whole grains deliver fiber to the microbiome, resulting in beneficial mental health effects.
• Omega-3- fatty acids in fatty fish can lower stress hormones and improve anxiety symptoms.
• Nutrient-rich fruits and vegetables contain elements such as magnesium, B vitamins, zinc, antioxidants, phytochemicals, and selenium, which are known to improve mental health.

The Mediterranean diet also moderates alcohol and restricts overly processed carbohydrates, also leading to lowered stress levels.

How to Make Changes in Your Diet

Here are some ideas for changing your diet to relieve stress:

• Eat real food: Shop around the grocery store’s perimeter and avoid prepackaged foods. Focus on fresh meat, fruits, vegetables, and whole grains.
• Cook at home: Restaurant meals often contain fat, sugar, and additives. You have more control over the food you cook at home.
• Read labels: Food with more than five ingredients or ingredients that you cannot pronounce is more processed.
• Conduct the great-grandmother test: Ask yourself if your great-grandmother would recognize a food product. If not, it is probably overly processed.
• Replace pantry food: Swap out processed food for whole grains. For example, replace processed cereal with oatmeal and sugary snacks with fruit.
• Try new recipes: Try a Mediterranean diet, Nordic diet, or anti-inflammatory cookbook or recipe online.

Changing your diet doesn’t have to be overwhelming. Slowly incorporating more brain-positive food and eliminating processed food won’t happen overnight, but the more nutritious food you consume, the better your health will be. You also don’t have to be perfect. Eating well 80–90% of the time will give you the same benefits.

Should I See a Dietician?

You can easily make several of these changes on your own. However, if you have a chronic medical condition such as diabetes, high blood pressure, high cholesterol, or obesity, a dietician can help you develop a plan tailored to your lifestyle and health needs. They can also help you determine how much of the three macronutrients you might need (fat, carbohydrates, and protein) and whether you are missing essential vitamins and minerals.

The Role of Diet in Managing Stress

The relationship between diet and stress is clear, and your choices can either improve or worsen your mental health. Incorporating nutrient-dense foods like nuts, fish, fermented food, and fiber-rich vegetables will strengthen your nervous system against stress, while making gradual changes toward a healthier diet can make you feel more calm and balanced.

However, mental health is complex and often requires treatment. You should seek professional help from a healthcare provider or therapist if you are struggling.