How Do Ultra-Processed Foods Affect Mental Health?

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Summary: Ultra-processed foods affect mental health in at least two ways: directly, by increasing risk of some mental health disorders, and indirectly, by increasing risk of chronic diseases associated with increased risk of some mental health disorders.

Key Points:

Ultra-processed foods (UPFs) are a common part of daily eating habits for millions of people in the U.S.
Consumption of UPFs has increased dramatically over the past 50 years.
New research shows UPFs increase risk of chronic disease and mental health problems
Previous research establishes the link between UPFs and chronic diseases, and the link between chronic disease and mental health problems.

Ultra Processed Foods and Health, Mental Health: New Research

In the study “Ultra-Processed Food Consumption and Risk of Multiple Chronic Diseases Among 8,819,894 Adults From 51 Prospective Cohorts: A Dose-Response Meta-Analysis,” an international group of researchers designed a study with the following goal:

“[To] comprehensively investigate the impact of consuming UPFs on the risk of major chronic diseases in adults.”

When we talk about lifestyle changes as an important part of mental health treatment, we often recommend increasing consumption of whole grains, fresh fruits and vegetables, and decreasing intake of processed and/or ultra-processed foods.

In this article, we’ll present the evidence behind that recommendation, and clarify the connection between ultra-processed foods and chronic disease, the direct connection between chronic disease and mental health, and the indirect connection between ultra-processed foods and mental health.

What is Ultra-Processed Food?

Using a classification system called NOVA – i.e. new – designed by a Portuguese physician in 2009 to categorize and study the increasing consumption of processed foods worldwide. The NOVA system:

“… groups foods according to the nature, extent and purpose of the industrial processing they undergo. Food processing as identified by NOVA involves physical, biological and chemical processes used after foods are separated from nature, and before being consumed or prepared as dishes and meals.”

It’s important to understand the four categories of food in this system:

Unprocessed or minimally processed foods. These may be altered by processes like basic food prep, as well as drying, crushing, grinding, freezing, etc. in order to make them more palatable and/or store them for future use.
Processed culinary ingredients. These include items like butters, oils, and salts processed by pressing, drying, milling, etc. and are not meant to be consumed alone, but rather used to help prepare unprocessed foods in group 1.
Processed foods. These include foods from group 1 altered by items in Group 2 to make a new item or increase durability (shelf life) of group 1 foods. Group 2 includes things like canned vegetables, fruits present in syrups, fresh breads, cheeses, and sweetened or thickened yogurt.
Ultra-processed foods. These are not modified foods, but rather “formulations made mostly or entirely from substances derived from foods and additives, with little if any intact Group 1 food.”

Foods in the ultra-processed group include sweet/savory packaged snacks, soft drinks, candies, reconstituted meat products, and pre-made frozen dishes. Ultra-processed foods (UPFs) have the following characteristics:

Energy dense
High in sugar and salt
High in fat
Low in dietary fiber, protein, vitamins and minerals
Contain multiple additives, such as colorings, flavors/flavor enhancers, non-sugar sweeteners, preservatives
Packaged for easy shelf life, sales, and preservation

For reference, here’s how consumption of UPFs changed among adults worldwide between 2001 and 2018, with additional historical data on UPF consumption in the U.S.

UPFs as a Percentage of Total Energy Intake

United States:

1970: 30%
1990: 40%
2001: 53.5%
2018: 57.0%

Spain:

2001: 11.0%
2018: 31.7%

Mexico and Brazil:

2001: 10%
2018: 23%

China:

2001: 3.5%
2018: 10.4%

That’s what UPFs are, compared to non-UPFs, and how consumption of UPFs has increased in recent decades. It’s easy to understand how these changes may have affected our overall health and wellness in the U.S. over the past 50 years.

Let’s look at the data from the study we introduce above, and learn how UPFs impact mental health both directly and indirectly.

How Ultra-Processed Foods Affect Mental Health: Direct and Indirect Impact

To understand the impact of UPFs on health, researchers analyzed results from 51 studies with data from close to 9 million participants, with an average age range of 22-77 years. Studies were conducted in the Americas, Europe, Asia, and Oceania.

First, let’s look at the direct impact on mental health, specifically on depression and anxiety:

4 studies with 228,597 participants
Hazard ratio (HR): 1.27

Consuming UPFs increases risk of developing clinical anxiety or depression by 27%, compared to people who don’t consume UPFs.

Next, let’s look at how consuming ultra-processed food can affect mental health indirectly. Evidence shows that chronic diseases can increase risk of developing mental health disorders. It follows, therefore, that if consuming UPFs increases risk of developing chronic disease, consuming UPFs has an indirect effect on mental health.

The study “Ultra-Processed Foods and Human Health: A Systematic Review and Meta-Analysis of Prospective Cohort Studies” shows consuming UPFs increases risk of common chronic diseases as follows:

Diabetes: 37% increased risk
Hypertension: 32% increased risk
Obesity: 32% increased risk
Elevated triglycerides (bad fat): 47% increased risk
Low HDL cholesterol (good fat): 43% increased risk

Now let’s look at how those chronic diseases, associated with UPFs, increase risk of mental health disorders:

Obesity, as reported in the study “Evaluating the Significance of Obesity or Excessive Weight in Various Mental Health Disorders: A Systematic Review”:

Relationship is bidirectional
People with mental illness have 200% increased risk of developing obesity
People with obesity have 30% to 70% increased risk of developing mental health disorders

Hypertension, as reported in the study “Associations between mental health, blood pressure and the development of hypertension | Nature Communications”:

Relationship is bidirectional
Presence of hypertension significantly increases risk of depression
Presence of depression can increase risk of hypertension

Diabetes, as reported in the resource “Diabetes and Mental Health,” published by the Centers for Disease Control (CDC):

Diagnosis of diabetes is associated with elevated risk of depression:
- 2 to 3 times higher risk than people without diabetes

Finally, this resource – “Understanding the Link Between Chronic Disease and Depression” – published by the National Institute of Mental Health (NIMH) succinctly summarizes the relationship between chronic disease and depression:

“People who have a chronic disease are at a higher risk of developing depression.”

We’ll discuss this information further, below.

Lifestyle Changes: Reducing Ultra-Processed During Mental Health Treatment and Recovery

One thing we learned from the study at the center of this article and our supporting research is how far from regular food what we call ultra-processed food really is. What we mean by regular food is eating, for instance:

Bananas
A plate of beans and rice
Broccoli with butter and garlic
A cheeseburger

Those are all either unprocessed foods, processed ingredients, or processed foods. They’re all recognizable as foods, and start off as unprocessed foods. However, ultra-processed foods are different. Here’s part of the definition again. UPFs are:

“…formulations made mostly or entirely from substances derived from foods and additives.”

That many things we eat that come in packages hardly even resemble food is now no surprise: from one point of view, they’re hardly even made of food. And research shows that these almost- or nearly- or derived from formulations are not only directly bad for our health, they can both directly and indirectly affect our mental health in a negative way.

This is important because what we eat is a controllable factor associated with mental health.

In a nutshell (unprocessed), we can say that consuming UPFs can increase risk of poor mental health. That’s an evidence-based assertion. Therefore, if you have a mental health disorder, we encourage you to decrease your consumption of ultra-processed foods.