Eating ultra-processed foods raises the risk of developing or dying from dozens of adverse health conditions, according to a new “umbrella review” of 45 meta-analyses. The authors found consistent evidence linking higher intakes of ultra-processed foods with over 70% of the 45 different health outcomes assessed.
The umbrella review, a high-level evidence summary, included 45 distinct pooled meta-analyses from 14 review articles associating ultra-processed foods with adverse health outcomes. The review articles were all published in the past three years and involved 9.9 million people. None of the studies were funded by companies involved in the production of ultra-processed foods.
Researchers graded each study as having credible or strong, highly suggestive, suggestive, weak or no evidence. All the studies in the review were published in the past three years, and none was funded by companies involved in the production of ultra-processed foods, the authors said.
Researchers found highly suggestive evidence that eating more ultra-processed foods raised the risk of obesity by 55%, sleep disorders by 41%, development of type 2 diabetes by 40% and the risk of depression by 20%.
However, evidence was limited for an association between consuming ultra-processed food and asthma, gastrointestinal health and cardiometabolic risk factors such as high blood fats and low levels of “good” high-density lipoprotein, or HDL, cholesterol, according to the analysis.
According to the authors, “Greater exposure to ultra-processed food was associated with a higher risk of adverse health outcomes, especially cardiometabolic, common mental disorder, and mortality outcomes. These findings provide a rationale to develop and evaluate the effectiveness of using population based and public health measures to target and reduce dietary exposure to ultra-processed foods for improved human health. They also inform and provide support for urgent mechanistic research.” (Lane et al., 2024)
The study found only suggestive or no evidence for an association between ultra-processed foods and cancer, which was a surprising finding, according to Dr. Fang Fang Zhang, a cancer epidemiologist at Tufts University, who has researched the role of ultra-processed foods and cancer.
“Obesity is a risk factor for 13 types of cancers. Ultra-processed foods increase weight gain, and obesity increases cancer,” she said. In an August 2022 study she coauthored, Zhang found men who ate the most ultra-processed foods of any type had a 29% higher risk of developing colorectal cancer.
“One reason for the unexpected finding is that research on ultra-processed foods is still in its infancy, said study coauthor Mathilde Touvier, research director at the French National Institute of Health and Medical Research, a public research organization.”
“We definitely need more studies to be able to upgrade the weight of evidence for cancer, for instance,” said Touvier, also the principal investigator of the NutriNet-Santé cohort, a long-term study of the relationship between nutrition and health.”
“So it’s not because there’s nothing there, it’s just because we need additional research,” she said. (LaMotte, 2024; Lane et al., 2024)
The making of ultra-processed foods
“Ultra-processed foods are much more than simply “modified” foods, said nutrition researcher Dr. Carlos Monteiro, head of the Centre for Epidemiological Studies in Health and Nutrition at the University of São Paulo in Brazil.”
“They are formulations of often chemically manipulated cheap ingredients such as modified starches, sugars, oils, fats, and protein isolates, with little if any whole food added,” said Monteiro, a professor of nutrition and public health, in an accompanying editorial.
“Monteiro coined the term ultra-processed food in 2009 when he developed NOVA, a system of classifying foods into four categories. Group one consists of unprocessed or minimally processed foods such as fruits, vegetables, eggs and milk. Group two includes culinary ingredients such as salt, herbs, oils and the like. Group three are processed foods that combine groups one and two — canned goods and frozen vegetables are examples.”
Group four are ultra-processed foods, which Monteiro said are made flavorful and enticing by using combinations of artificial flavors, colors, thickeners and other additives that have been “linked by experimental and epidemiological evidence to imbalances in gut microbiota and systemic inflammation.”
“No reason exists to believe that humans can fully adapt to these products,” Monteiro wrote in the editorial. “The body may react to them as useless or harmful, so its systems may become impaired or damaged, depending on their vulnerability and the amount of ultra-processed food consumed.”
“Since Monteiro’s definition of ultra-processed food appeared, nutritionists, researchers and public health officials have grown concerned about the increasing prevalence of such foods in the United States, Australia, the United Kingdom, Canada and many developing nations.”
“Two-thirds of the calories children consume in the US are ultra-processed, while about 60% of adult diets are ultra-processed,” Zhang said.
“I think it’s like when we invented cars,” she added. “Yes, they bring us convenience, but if we use a car for everything and we don’t exercise we have problems. We need new strategies to bring down the consumption of ultra-processed food to a healthier level.” (LaMotte, 2024; Lane et al, 2024)
How to reduce the use of ultra-processed foods
Prepare food and cook it at home. Experts also agree that in today’s fast-paced world, giving up the convenience of ready-to-heat and ready-to-eat foods is difficult. In addition, it’s nearly impossible to avoid them, as over 70% of the US food supply is comprised of ultra-processed food.
Regulation by public health agencies and governments should be considered, Monteiro said, such as front-of-pack warning labels; restriction of advertising, especially to children; and the prohibition of sales of ultra-processed foods in or near schools and hospitals, all while making minimally processed foods more affordable and accessible. (LaMotte, 2024; Lane et al, 2024)
Below are examples of octagonal nutrient warning labels that exist on food and beverages in Mexico, Colombia, and other countries in Latin America:
To reduce one’s intake of ultra-processed foods, take the following steps:
1. Read and compare product labels and try to choose less processed alternatives. For example, swap flavored yogurt for plain yogurt with added fruit.
2. Focus on what you can add to your diet (as opposed to take away) such as fresh or frozen fruits, vegetables, beans, and legumes.
3. Be mindful of beverages. Sugar-sweetened beverages have no nutritional value. Swap them out for water.
4. When eating out, go to local restaurants and cafés instead of fast-food chains. Local eateries are less likely to make ultra-processed foods.
5. For children, fill their plates with plenty of whole foods, including fresh fruits and vegetables, nuts, whole grains, and legumes (such as beans, peas, and lentils). Cut back on the amount of ultra-processed foods in their diets. The American Academy of Pediatrics (AAP) reports that glyphosate, a broad-spectrum herbicide, is present in many foods, especially ultra-processed foods. Many genetically engineered (GE) crops are engineered to survive being sprayed with the glyphosate – a broad-spectrum herbicide – during the growing season. Most GE crops are grown to make ultra-processed foods and animal feed. The AAP recommends reading food labels carefully, and consider choosing foods and drinks that are free of genetically-engineered ingredients (look for the Non-GMO Project Verified label, or organic certified label), whenever possible (Abrams & Landrigan – AAP, December 2023).
References
Lane ML, Gamage E, Du S, et al. Ultra-processed food exposure and adverse health outcomes: umbrella review of epidemiological meta-analyses. BMJ. 2024;384:e077310 https://www.bmj.com/content/384/bmj-2023-077310
Monteiro CA, Martínez-Steele E, Cannon G. Reasons to avoid ultra-processed foods. Editorial. BMJ. 2024;384:q439. https://www.bmj.com/content/384/bmj.q439
Southey F. Ultra-processed food linked to 32 poor health outcomes in largest study to date. March 5, 2024. Food Navigator – Europe. Available at: https://www.foodnavigator.com/Article/2024/03/05/Ultra-processed-food-linked-to-mortality-in-largest-UPF-study-to-date
LaMotte S. Ultraprocessed foods linked to heart disease, diabetes, mental disorders and early death, study finds. CNN. February 28, 2024. Available at: https://edition.cnn.com/2024/02/28/health/ultraprocessed-food-health-risks-study-wellness/index.html
Wang K, Du M, Khandpur N. Association of ultra-processed food consumption with colorectal cancer risk among men and women: results from three prospective US cohort studies. BMJ. 2022;378:e068921.
Abrams SA, Landrigan PJ. Are GMO Foods Safe for My Child? AAP Policy Explained. American Academy of Pediatrics (AAP). December 2023. Available at: https://www.healthychildren.org/English/healthy-living/nutrition/Pages/are-GMO-foods-safe-for-my-child-AAP-policy-explained.aspx
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