Eating junk food is as pervasive in our current culture as eating naturally was in our not-so-long-ago past—and it shows. A systematic review published in The BMJ this year, involving 9.8 million participants, indicated an association between the consumption of ultra-processed foods and an increased risk of 32 diseases, including heart disease, cancer, Type 2 diabetes, anxiety, and premature death.
Dr. Zheng Yuanyu, former attending physician of the Infectious Disease Department at Taipei Veterans General Hospital in Taiwan, discussed the addictive nature of ultra-processed foods and strategies for managing their consumption rationally on the “Health 1+1” program.
What Are Ultra-Processed Foods?
Some examples of ultra-processed foods include ready-to-eat meals, packaged baked goods, snacks, sugary cereals, and carbonated drinks, according to a BMJ Group press release. These items undergo multiple industrial processing steps and typically contain colorings, emulsifiers, flavorings, and other additives. Additionally, they are often high in added sugars, fats, and salts, while being low in fiber and vitamins.
Dr. Zheng noted that the definition of “processed foods” is broad, and not all processed foods are classified as “ultra-processed” or unhealthy. For example, he said, foods that are heated and sealed in a factory are considered minimally processed. However, some simple processed products can still be unhealthy. The most common ultra-processed foods, such as various snacks, beverages, and factory-produced cookies and bread, undergo more complex manufacturing processes and contain multiple chemical additives, resulting in a less healthy nutritional profile.
7 Health Risks of Ultra-Processed Foods
The BMJ review included 45 distinct studies involving over 9.8 million participants. The results multitude of adverse health outcomes revealed by the review can be broadly classified into the following seven categories:
- Mortality: All-cause mortality, cancer-related mortality, cardiovascular disease-related mortality, and heart disease-related mortality.
- Cancer: Overall cancer, breast cancer, colorectal cancer, central nervous system tumors, chronic lymphocytic leukemia, pancreatic cancer, and prostate cancer.
- Mental health: Poor sleep, anxiety, common mental disorders, and depression.
- Cardiovascular health: Cardiovascular disease, hypertension, hypertriglyceridemia, and low HDL cholesterol levels.
- Respiratory health: Asthma and wheezing.
- Gastrointestinal health: Crohn’s disease and ulcerative colitis.
- Metabolic health: Abdominal obesity, high blood sugar, metabolic syndrome, non-alcoholic fatty liver disease, overweight, obesity, and Type 2 diabetes.
The researchers assessed the credibility and quality of evidence from various studies and found that excessive consumption of ultra-processed foods was particularly associated with a higher risk of cardiometabolic issues, common mental disorders, and mortality outcomes.
Specifically, the researchers noted that “compelling evidence” indicated a higher intake of ultra-processed foods was linked to a 50 percent increased risk of cardiovascular disease-related mortality, as well as a 48 to 53 percent increased risk of anxiety and common mental disorders. Furthermore, it was associated with a 12 percent increased risk of Type 2 diabetes.
Additionally, highly suggestive evidence showed that a higher intake of ultra-processed foods was associated with a 21 percent increased risk of all-cause mortality, a 22 percent increased risk of depression, and a 40 to 66 percent increased risk of heart disease-related mortality, Type 2 diabetes, obesity, and sleep problems.
Dr. Zheng highlighted that while ultra-processed foods are linked to numerous diseases, this does not necessarily indicate a direct causal relationship. However, he specifically emphasized that the evidence connecting ultra-processed foods to diabetes is the most compelling, with relatively high-quality research supporting this association. Diabetes can deteriorate vascular and immune functions throughout the body, increasing the risk of various other diseases in patients already predisposed to diabetes.
Dr. Zheng cited a study published in JAMA Network Open in 2023, which explored the association between ultra-processed foods and the risk of mental illness. The study suggested that ultra-processed foods may increase the likelihood of developing depression. The researchers tracked more than 30,000 health care professionals for 15 years and found that individuals in the highest quintile of ultra-processed food intake had a 49 percent higher risk of depression compared to those in the lowest quintile. The study revealed that eating more ultra-processed foods, especially those containing artificial sweeteners, significantly increased the risk of depression.
The Addictive Nature of Ultra-Processed Foods
A 2023 study published in The BMJ estimated that approximately 14 percent of adults and 12 percent of children may experience issues related to ultra-processed food addiction.
Dr. Zheng stated that issues related to ultra-processed food addiction, much like smartphone and alcohol addiction, can significantly impact mental health. He explained that the complex ingredients in ultra-processed foods, such as refined carbohydrates and fats, can stimulate the brain to release large amounts of dopamine, reaching levels similar to those triggered by substances like nicotine and alcohol, thereby contributing to addiction.
Furthermore, Dr. Zheng pointed out that ultra-processed foods are high in refined carbohydrates and often contain added fats and chemical additives. Due to various processing methods, these foods can produce certain effects that disrupt the body’s appetite regulation mechanisms, leading to increased calorie consumption without realizing it. The long-term accumulation of excess calories can, in turn, result in subsequent health issues.
Health Tips for Moderating Ultra-Processed Food Intake
In today’s environment, the temptation of ultra-processed foods is unavoidable. Dr. Zheng emphasized the importance of recognizing the addictive nature and health hazards of these foods. They should be enjoyed in moderation, avoiding excessive consumption. If signs of addiction appear, early intervention is crucial.
Among ultra-processed foods, it is recommended to choose relatively healthier options. For instance, for breakfast, opt for cereals that are lower in sugar, sodium, and salt, and higher in fiber, while avoiding refined carbohydrates. Additionally, mixing sugary cereals with unsweetened ones can help reduce the overall sugar content.
Dr. Zheng used a popular chocolate cake product as an example, highlighting that its ingredient list contains a significant amount of chemical additives, such as complex thickeners, emulsifiers, and agents for improving baking fat quality. Each 3.53 ounces (100 grams) of the cake contains 0.93 ounces (26.3 grams) of sugar, which accounts for over a quarter of its composition, indicating a very high sugar content, along with 0.62 ounces (17.7 grams) of fat. Dr. Zheng cautions that such a cake should not be consumed as a daily snack and should be avoided unless there is a special occasion.