We Are What We Eat: Ultra-Processed Foods and Mental Health

By Erin O'Neil, LCSW.

The holiday season is one we prepare for with both excitement and a certain amount of dread. There can be so much magic and, simultaneously, so much stress. And, it is not just the pressure of gift-giving. There is social anxiety (there are a lot of parties), grief and sadness, discomfort with family members, and a lot of food. It feels like everywhere we turn there are cookie platters, charcuterie boards, chocolate in varying forms, and candy. But how do the seasonal party foods even compare to the stress levels brought on by financial strain, social anxiety, and grief? Well, it turns out the ultra-processed foods that feel pretty much unavoidable this season may contribute to worsening mental health.

The NOVA Food Classification System: Where Do We Fall?

Carlos Monteiro, a professor of Nutrition and Public Health at the University of Sao Paolo in Brazil, developed the NOVA food classification system, which identifies and categorizes foods based on their nature. The four categories are: 1. Unprocessed or minimally processed foods, which include whole foods with their vitamins and minerals still unbroken, 2. Those foods meant to extend food shelf-life (e.g., fats and spices or herbs), 3. Processed foods, which are those that combine categories one and two to create foods comprised of minimal ingredients (e.g., breads), and 4. Ultra-processed foods, which are foods that include a lot of added ingredients. These are the kinds of products with a long list of ingredients that you can’t recognize, spell, or pronounce.

Ultra-processed foods tend to contain increased amounts of sodium, added sugars, preservatives, and artificial colors, and they are very far removed from the whole foods category or foods in their purest forms. A 2019 study estimated that about 70 percent of packaged foods sold in the United States fall into the ultra-processed food category with about 60 percent of our calories coming from ultra-processed foods.

Young couple placing grocery bags in their trunk.

Source: PhotoAttractive / istock

What Are the Impacts?

Despite being a dietary staple, ultra-processed foods continue to negatively affect our physical and mental well-being. We are well aware of the physical health toll diets high in ultra-processed foods can have; think, Type 2 Diabetes, Obesity, and Cardiovascular Disease, to name a few. Those with gastrointestinal issues ranging from Irritable Bowel Syndrome to Crohn’s and Colitis have an intimate knowledge of the impact of food on physical health and our bodies’ abilities to function.

Current research studies the potential correlation between ultra-processed foods and cognitive decline as we age. Professor Felice Jacka is a Professor of Nutritional Psychiatry, Director of the Food & Mood Centre at Deakin University, and the founder and president of the International Society for Nutritional Psychiatry. In a 2023 episode of the Zoe Podcast, which focuses on health, Professor Jacka discusses the impact of ultra-processed foods on our hippocampus. This part of the brain is responsible, in part, for emotional behavior, storing long-term memories, and regulating our appetites. According to Professor Jacka, the hippocampus is one of the only parts of the brain that can grow and shrink throughout our lifetimes. Part of her research investigates how ultra-processed foods may actually contribute to the shrinking of our hippocampus, having implications for our emotional behaviors and our ability to remember or/recall long-term memories.

A Closer Look at Depression, Anxiety, and Ultra-Processed Foods

While the physical impacts of ultra-processed foods are well-documented with ongoing research, we do not tend to associate the foods we put into our bodies as having a direct impact on our mental health. Depression is one of the most common mental health issues we see in the United States with about 21 million adults struggling with major depression each year. About 3.7 million youth (15 percent) are affected by major depression. Over 40 million adults in the United States struggle with anxiety. This equates to about 19 percent of our adult population. Now, anxiety and depression are caused and impacted by different factors, including attachment/relationships, socioeconomic status, racial, gender, and sexual identity factors, and trauma history, to name a few. However, a diet comprised of ultra-processed foods can exacerbate these symptoms. In my experience in substance use care, we often talk about cross-addiction, and one area we can see this is in food. I work with a lot of individuals who, once they have stopped using their substance, will start drinking more energy drinks, eating more junk food, and will simultaneously experience difficulties with sleep, staying awake, feelings of depression, anxiety, low energy, etc. While ultra-processed foods are not necessarily the sole cause of these challenges, they do not help when someone is trying to find healing in recovery.

Ultra-processed foods are often devoid of the vitamins and minerals we need. There is evidence demonstrating the correlation between certain vitamin deficiencies and specific mental health impacts. Insufficient B12, B9 or folate, and zinc can contribute to low mood, fatigue, exhaustion, and irritability. Vitamin D helps regulate the genes that make serotonin and oxytocin, two of our body’s chemicals that help us experience pleasure. A lack of Vitamin D can influence our mood, alertness, motivation, memory, and pleasure. Vitamin B6 is also a huge factor in the production of these same pleasure chemicals, including dopamine, and GABA, which is the hormone released to calm our nervous system when we experience sudden anxiety. Magnesium and iron aid in mood stabilization. When we are not getting enough iron, we can experience fatigue, exhaustion, and struggle with concentration.

Broadening research explores the impact of dietary patterns on our mental health. There appears to be a correlation between diets high in ultra-processed foods, or a “Western dietary pattern,” and the development of depression and ADHD. Since nothing exists in isolation, additional risk factors such as food insecurity and lack of access to nutritious and culturally appropriate foods contribute to the development of various mood symptoms such as depression and anxiety. Diets rich in “whole foods,” seem to be a protective factor against developing mood disorders, notably, depression. In one study of about 10,000 university students, researchers followed students who stuck to a Mediterranean Diet over four years. The Mediterranean Diet is rich in whole foods, including fish, vegetables, whole grains, and healthy fats such as olive oil. The study found that the students who most closely followed this diet had about a 40 percent reduced risk of developing depression.

Bringing Nutrition Into Wellness Plans

While research in nutritional psychiatry is fairly new and ongoing, practitioners can integrate some of these preliminary findings and knowledge into their work. Regardless of the specific issues in which we work (depression, anxiety, trauma, substance use and addiction, severe mental health), nutrition and diet should be considered as part of one’s wellness, as they work towards better health and healing—physically, mentally, and emotionally. As we gather each client’s history and get a sense of how their presenting issues have developed, we can explore diet just as we do any disordered eating habits and medical history. By taking a closer look at what individuals are putting into their bodies, we may see patterns that contribute to those mental health issues with which they are presenting.

Diet Essential Reads

The Body Mass Index Fallacy

3 Psychological Barriers That Make It Hard to Go Vegan

When partnering on a wellness plan, we can incorporate nutrition interventions, just as we do psychiatric, medical, and community supports. When identifying triggers and coping skills with clients, we should explore how energy drinks, high amounts of sugar, and processed carbohydrates may exacerbate their exhaustion, depression, and anxiety. We can refer to and collaborate with nutritionists. When discussing coping skills with our clients, we can incorporate physical healthcare (sleep, nutrition, hydration, physical movement) in addition to breathwork, sensory skills, community supports, specific forms of therapy, and medications.

While we should not provide guidance outside of our scopes of practice, this is an opportunity for those of us in mental health to broaden our understanding of triggers, symptoms, and supports, and to collaborate with our clients and experts to identify a more holistic and comprehensive approach to health and healing.

About Erin O'Neil, LCSW

Erin is a Licensed Clinical Social Worker, Eye Movement Desensitization and Reprocessing International Association-certified clinician, and EMDR Consultant in Training with ample experience in the treatment of addiction and post-traumatic stress. Through modalities such as Motivational Interviewing, IPNB, Ego State Therapy, and Somatic Experiencing, she collaborates with clients who are working toward healing. In her current role, Erin uses a trauma-informed approach to help clients develop coping skills as well as process and resolve the deeper issues that contribute to their addictions.