Food and Mood: What You Eat Matters

Imagine this.

You know it’s going to be a busy day for you, and that usually means kickstarting the day with a nice, warm cup of black coffee.

You leave home and travel to work. You feel optimistic about the day ahead as you feel the energy running through your body. Once you reach work, you are laser-focused on completing the tasks you have.

By lunchtime, it’s time to top-up your energy. You order a diet Coke together with your lunch. Less sugar, the same amount of caffeine. You believe this will help you sustain your energy for the day.

You get back to work eager to finish the day strong. You do until it’s around 4 pm, and you feel drained as if the energy was sucked out of you in a snap of a finger.

Then, you are doing everything you can to hold it together as work finishes for the day. You feel desperate to go home. You feel exhausted. Even traveling back to your home feels like a chore. Sleeping early is the only comforting thought you have at that moment.

You arrive at home. Eat dinner early. Have a warm bath, and go to sleep early.

The next day, you wake up feeling fresh, excited to conquer the day again. So you grab a cup of coffee before leaving your house.

Does this story sound familiar to you?

Food and Your Brain

There’s a reason why caffeine and sugar can give you that quick boost of energy and betrays you later in the day. You might think the hype up is worth it. However, crashing at the end of the day can make you feel more anxious and may even lead to depression. Here’s why.

What you eat affects your brain more than you realize. A car won’t run its best without using high-quality fuel. It’s the same with the brain. If you want your brain to be in tiptop shape, you have to eat high-quality foods that contain antioxidants, vitamins, and minerals. These foods nourish the brain and keep away free radicals and oxidative stress from damaging brain cells.

Nutritional Psychiatry is an emerging field in nutrition, dietetic, and psychological sciences. It studies the relationship between food intake and mental health. (1) Nutritional psychiatrists explore the causes of brain inflammation through unhealthy heating. They’ve discovered that inflammation in the brain is one of the causes of mental health illnesses. And thus, healthy eating can help prevent inflammation altogether as well as improve cognitive function, thereby reducing the risk of mental health issues in people.

How does food produce inflammation anyway?

You may have heard of serotonin, also dubbed as the happy chemical or happy hormone in the body. More than making you feel better, serotonin is also a neurotransmitter and helps stabilize moods, regular appetite, and improve sleep quality.

In the gastrointestinal tract or the gut, there are over a hundred million neurons. These neurons help the gut digest food and guide emotions. They also produce serotonin with the help of billions of good bacteria in the gut. Ninety-five percent of the serotonin in the human body is produced there.

The gut flora or gut microbiome is composed of bacteria, fungi, protozoa, and viruses. All of these play a role in keeping the gut flora balanced. However, it is the good bacteria in the gut that will benefit the human body the most. One of their most important roles is to protect the gut lining from toxins and bad bacteria. They also help in the absorption of nutrients from the food you eat. More importantly, they limit inflammation and activate the neural pathway between the gut and the brain.

What does this mean for you? When you are not eating healthy, your gut flora becomes unbalanced. There is a decrease in the number of good bacteria in your gut, hence, reducing the gut’s ability to prevent inflammation.

One study found that “A dietary pattern characterized by high consumption of red and/or processed meat, refined grains, sweets, high-fat dairy products, butter, potatoes and high-fat gravy, and low intakes of fruits and vegetables is associated with an increased risk of depression.” (2)

Many studies have the same findings. One of which monitored the 6,500 women who ate anti-inflammatory diets (filled with vitamins, high-quality protein, healthy fats, antioxidants) over 12 years. The study showed that these women had a 20% lower risk of having depression than women of the same age. (3) Here are other studies you can read:

Foods to Watch Out For

  • Gluten

Foods with gluten are high-inflammatory foods. It irritates the gut, intestinal tissues, and gut microbes. It also produces a zonulin, a compound that can lead to a leaky gut or intestinal permeability. (5)

One study showed the adverse effects of gluten in the gut microbe of healthy study subjects. The study found that this can result in depression. Apart from depression, studies found that eating gluten can lead to headaches, seizures, multiple sclerosis, anxiety, Attention Deficit Hyperactive Disorder (ADHD), and nerve damage.

  • GMO’s

Genetically-modified organisms (GMOs) are toxic to microbial cells. It is heavily treated with herbicides and pesticides. One of which is glyphosate, which has been studied for its ability to cause cancer. (5) Another more concerning fact about GMOs is that they’ve been found in breastmilk and fetuses. This means that mothers are transferring it to their babies. Studies have shown a connection between glyphosate and premature births and babies weighing less.

How does this affect mental health? GMOs create problems in the gut, specifically, leaky gut. GMOs weaken the intestinal lining and thus, intestinal permeability lets undigested food particles leave the gut and travel through the bloodstream. The body cannot recognize these food particles and see them as intruders. This is when an inflammatory reaction occurs which is harmful to the brain.

  • Dairy

Many people love dairy, which makes it hard to hear that dairy can lead to inflammation. The protein responsible for that is casein, which has been linked to depression and schizophrenia. For those experiencing anxiety and depression, excluding dairy in the diet for a month is recommended.

  • Sugar

It’s not hard not to love sugar, which is why many people rely on sugar to give them that energy rush they need. It’s addicting, the more you eat sugar, the more you’ll crave for it.

The problem is hypoglycemia. The human body cannot handle the ups and downs of blood sugar in the body. For instance, drinking soda can instantly increase blood sugar, spiking up insulin which damages the gut microbiome.

The insulin will then remove blood sugar, causing you to have a blood sugar crash. Then, an increased number of cortisol (stress hormones) will come to the rescue to help out by putting back the sugar into the bloodstream.

The brain needs a steady amount of sugar to function well, so there’s no need to completely eliminate sugar in your diet. The key is balancing blood sugar to prevent inflammation, and thus, keep depression and anxiety at bay. 

Too much sugar can also damage cell membranes and blood vessels. Watch out for high-fructose corn syrup, crystalline fructose, cane sugar, and maltodextrin in food labels. These are all types of sugar.

What about artificial sweeteners? Two of the most popular artificial sugars are sucralose and aspartame. They are known to have zero calories. The problem lies in the body’s inability to digest them, which just confuses the hormones and the gut microbiome. One study showed the link between artificial sugars and gluten intolerance, insulin resistance, and diabetes.

If you have a sugar craving, opt for natural sugars. Eat honey or fruits instead.

  • Vegetable Oils

Vegetable oils are unhealthy fats and yet, they’re often marketed as healthy. The processed foods you buy are filled with different vegetable oils like soybean, sunflower, safflower, corn, and canola oil. Why are they unhealthy? Vegetable oils are considered processed oils, meaning they were made with chemical solvents, high-pressure, and high heat. Plus, these oils often come from GMOs, too.

The body has a hard time recognizing vegetable oils, which leads to inflammation. Studies have shown the link between processed vegetable oils and cancer, mental health issues, heart diseases, and thyroid dysfunction.

Specific Conditions

Here’s a quick guide on how poor diet can develop mental health issues: (6)

  • Depression – may be caused by low folic acid, zinc, vitamins B1, B2, C
  • Schizophrenia – may be caused by low levels of polyunsaturated fatty acids, lower antioxidant enzymes in the brain
  • Dementia – low intake of vitamins and minerals, high fat intake, low intake of vitamin C and E
  • ADHD – deficiency in zinc, iron, magnesium, lack of essential fatty acids

Take Care of Yourself

The best advice is to take care of yourself and be responsible for your health. If you haven’t been paying attention before, this is the time to start. If you’ve been eating a poor diet and thought that it couldn’t be “that bad,” well, it is. Know that it doesn’t only affect your physical body but your brain, too. 

Stop relying on quick pick-me-ups that will only make you crash later on. Stick to healthy snacks and food that will help you sustain your energy longer and keep your body healthier in the long run.

“Take care of your body. It is the only place you have to live. ” – Jim Rohn



  1. What is Nutritional Psychiatry (Mental Health Nutrition)?
  2. Dietary patterns and depression risk: A meta-analysis
  3. Association between inflammatory potential of diet and risk of depression in middle-aged women: the Australian Longitudinal Study on Women’s Health
  4. Leaky gut: What is it, and what does it mean for you?
  5. Glyphosate Fact Sheet: Cancer and Other Health Concerns
  6. Food for thought: Mental health and nutrition briefing