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How Food Affects Your Mood

Contributor Andrew T. Chan, MD, MPH
8 minute read
A woman eating a bowl of fruit.

What you eat matters. Good nutrition can help prevent chronic illnesses such as heart diseaseobesity, and diabetes. Now, evidence is mounting that our food choices can affect our mental health and mood.

“Think about your diet as something you can control and use to potentially improve not only your physical health but also your mental health,” says Andrew T. Chan, MD, MPH. Dr. Chan is a Mass General Brigham gastroenterologist who cares for patients at Massachusetts General Hospital. He focuses on the relationships between gut health and other aspects of well-being.

Certain foods might provide instant satisfaction and make you feel good in the moment, but if you eat in a healthier way, you can feel better the next day — and in the long term.

There’s a clear link between what you’re eating, how you’re eating, your well-being, and your subjective feelings of energy and mood.

Andrew T. Chan, MD, MPH
Mass General Brigham

How does nutrition affect mental health?

“There’s a clear link between what you’re eating, how you’re eating, your well-being, and your subjective feelings of energy and mood,” Dr. Chan says. But how does eating healthy affect your mental health? Several biological mechanisms and biochemical processes in the body are involved in the gut-brain connection:

  • Inflammation: Inflammation can disrupt brain chemicals, such as serotonin and dopamine, which are important for regulating mood. Certain foods are more likely to cause inflammation in the body, but others can reduce inflammation.

  • Glucose: Our levels of blood glucose (sugar) spike and dip in response to the things we eat. Drastic changes in glucose levels can therefore come with mood swings. Eating specific foods or foods in combination that stabilize blood sugar can help level out mood swings.

  • Gut microbiome: The gut microbiome encompasses bacteria that naturally exist in your gastrointestinal system. Some evidence indicates that certain types of microbes break down certain types of foods into chemicals that affect the way the brain functions, including regulating mood. Other research is starting to show that people who have issues with mood and mental health may have an altered gut microbiome.

Research is continuing to explore details about how these mechanisms work. In the meantime, Dr. Chan offers practical strategies to improve mood and help ward off mood disorders:

  • Limit ultra-processed foods.

  • Eat more fruits and vegetables.

  • Drink coffee and tea, which encourage your body to release dopamine, a natural mood enhancer.

  • Keep a food journal to gain a better understanding of how food affects your mood.

Researchers at Mass General Brigham are heavily involved in efforts to explore the mechanisms of food and mood, particularly ways to personalize your diet. As part of the PREDICT study, they are examining why some people respond differently to the same foods.

Mass General Brigham teams are also participating in the Nutrition for Precision Health Study, funded by the National Institutes of Health. The study is developing algorithms that can help predict individual responses to food and diet.

Avoid highly processed foods.

Foods that may improve mood include this salad of vegetables and eggs.

“Ultra-processed foods are foods that are ready to eat and often have a lot of additional additives to make them taste better — basically foods that you can take off the shelf and eat right away or buy quickly from a fast-food vendor,” Dr. Chan says.

These types of foods tend to have a lot of sugar or artificial sweeteners but lack important nutrients. They can cause chronic inflammation, spike blood sugar, and affect the gut microbiome — which can all affect mood. Recent research has established a link between highly processed food and mental health.

“We recently completed a study that looked at people’s consumption of ultra-processed foods and followed them over time to find a link between healthy eating and depression risk,” says Dr. Chan. “The individuals who ate the highest levels of ultra-processed food tended to have a higher risk of developing subsequent depression.”

He recommends eating more whole foods, which are foods that more closely resemble how they’re found in nature. Whole foods are richer in nutrients your body and brain need to function at their best.

Examples of whole food include:

  • Whole grains, such as whole wheat bread and pasta

  • Vegetables and fruit (fresh, frozen, and canned)

  • Meat, poultry, and seafood

  • Eggs, nuts, and seeds

Drink coffee or tea.

Dr. Chan points to research showing that coffee and tea are associated with better mood and mental health. Both caffeinated and decaf options are effective, because they both stimulate the release of chemicals in the body that improve mood.

However, he cautions against too much caffeine or sugary additives. They can have detrimental effects on anxiety and sleep — and therefore mood.

Keep a food journal.

Dr. Chan encourages people to keep a food journal to discover how food affects their mood. Track things like:

  • What did you eat and drink, and how much?

  • When did you eat? For example, before or after physical activity, or right before bed.

  • Did you skip a meal?

  • Were you in a good mood or a bad mood at times during the day?

  • Did you have any symptoms that might be related to food and mood? For example, did certain food choices lead to heartburn that kept you awake at night, making you tired and cranky the next day?

  • How does junk food affect you emotionally?

  • How does eating healthy affect you emotionally?

“People don’t often actually remember what they eat. If you track your food and beverages you can start to construct better nutrition and a better dietary schedule. What are the optimal times of the day for you to eat? Are you giving yourself enough time to eat so you can have a healthier meal? Are you eating at times of day to get the right level of energy for daily activities?” Dr. Chan says. “When you take into account not only the food you’re eating, but also the context in which you’re eating, you can gain some interesting insights into food and your mood.”

Andrew T. Chan, MD, MPH