Ultraprocessed foods account for more than half of calories consumed at home

U.S. home consumption of ultraprocessed foods increasing at faster pace than consumption outside the home

Johns Hopkins Bloomberg School of Public Health

A new analysis led by researchers at the Johns Hopkins Bloomberg School of Public Health found that more than half of calories consumed at home by adults in the U.S. come from ultraprocessed foods.

Ultraprocessed foods contain substances with little or no nutritional value, such as colorings, emulsifiers, artificial flavors, and sweeteners. Examples cover a wide range of products, from chips and hot dogs to prepackaged meals. Researchers have long understood that a substantial proportion of the U.S. diet comes from ultraprocessed foods but it was not clearly understood where those calories were consumed.

Consuming high amounts of ultraprocessed food has been linked to chronic health conditions—cardiovascular disease, obesity, colorectal cancer, among others. The new findings suggest additional measures are needed to promote healthier alternatives for preparing meals at home. 

The study was published online December 5 in the Journal of Nutrition. 

“The perception can be that ‘junk food’ and ultraprocessed foods are equivalent,” says Julia Wolfson, PhD, MPP, associate professor in the Bloomberg School’s Department of International Health and the study’s lead author. “Yet ultraprocessed foods encompass many more products than just junk food or fast food, including most of the foods in the grocery store. The proliferation and ubiquity of ultraprocessed foods on grocery store shelves is changing what we are eating when we make meals at home.” 

For their analysis, the researchers used data from the 2003–2018 National Health and Nutrition Examination Survey (NHANES), a nationally representative annual survey of more than 34,000 adults over 20 years of age.

On two separate days, NHANES participants were asked about the foods they had eaten in the past 24 hours and where they had consumed the food—at home or away from home. Using the Nova Food Group Classification—a well-established framework for grouping foods by level of processing—foods were assigned to one of four categories: 1) unprocessed or minimally processed, 2) processed culinary ingredient, 3) processed, 4) ultraprocessed. 

The researchers compared ultraprocessed to minimally processed food intake. Foods with artificial ingredients and colors, including many fast foods and prepacked meals available at grocery stores, were categorized as ultraprocessed foods. Fruits, vegetables, and other whole foods, including frozen and dried foods without additional salt or other ingredients, were considered minimally processed foods. 

Overall, ultraprocessed foods comprised more than half of all calories consumed at home, rising from 51% in 2003 to 54% in 2018. The researchers found only minor differences in trends of ultraprocessed food intake at home by sex, age, race/ethnicity, income, and education over the study period. Ultraprocessed food intake at home was slightly lower than 50% in some years from 2003 to 2018 for two groups: Hispanics and higher-income households. The proportion of at-home calories from ultraprocessed foods never fell below 49% for the high-income group or 47% among Hispanics.

About one-third of all calories came from eating foods away from home. For those with less than a high school degree, away-from-home consumption of ultraprocessed foods rose nearly eight percentage points, from 59.2% in 2003 to 67.1% in 2018 of all away-from-home calories consumed in 2018. That proportion hovered around 60% for individuals with a high school degree or more. 

Overall, the proportion of total calories from minimally processed foods fell nearly five percentage points from 33.2% in 2003 to 28.5% in 2018, and minimally processed food intake declined both at home and away from home for most groups. These results, the authors say, speak to the many challenges of procuring and preparing minimally processed, scratch ingredients such as fresh vegetables, meat, and fish. Ultraprocessed foods tend to be easier and faster to prepare, and often are less expensive and more shelf stable than scratch ingredients.

“We need strategies to help people choose less processed foods and avoid unhealthy ultraprocessed foods for foods purchased for both at-home and away-from-home consumption,” adds Wolfson. “Additionally, strong nutrition labels warning of high ultraprocessed food content may be warranted.”

The authors note that the study has limitations, including possible reporting bias—people may underreport eating foods that they believe are not good for them. The authors also note that the study period occurred before the pandemic and does not reflect changes in at-home food consumption during this period.

The study was supported by the National Institute of Diabetes and Digestive and Kidney Diseases(#K01DK119166) and the National Heart, Lung, and Blood Institute (R01 HL153178 and T32 HL007024). 

“Trends in Adults’ Intake of Un-processed/Minimally Processed, and Ultra-processed foods at Home and Away from Home in the United States from 2003–2018” was written by Julia A. Wolfson, Anna Claire Tucker, Cindy W. Leung, Casey M. Rebholz, Vanessa Garcia-Larsen, Euridice Martinez-Steele.

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Journal

Journal of Nutrition

Ultra-processed foods may drive colorectal cancer risk, USF-TGH study finds

Chronic inflammation, fueled by poor dietary choices, plays a vital role in the growth and progression of colorectal cancer

University of South Florida

 

video: 

Dr. Timothy Yeatman and Ganesh Halade in the lab analyzing tumors.

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Credit: USF

Media Contact:
John Dudley
(814) 490-3290 (cell)
jjdudley@usf.edu

EMBARGOED FOR PUBLICATION UNTIL TUESDAY, DEC. 10, AT 10 A.M. ET

TAMPA, Fla. (Embargoed until Dec. 10, 2024) – Colorectal cancer, the second leading cause of cancer-related deaths in the United States, may be fueled by the food on our plates. Researchers at the University of South Florida and Tampa General Hospital Cancer Institute have uncovered a potential link between the Western diet – dominated by ultra-processed foods and unhealthy oils – and the chronic inflammation that drives tumor growth.

The researchers, through a five-year, $3.1 million grant from the National Institutes of Health, have already made major advancements in the understanding of colorectal cancer. The project’s first study examines how processed foods are likely hindering the body’s natural healing processes. Their findings will publish online in Gut, a leading international journal in gastroenterology and hepatology, on Tuesday, Dec. 10, at 10 a.m. ET, and the embargo will lift at that time.

“It is well known that patients with unhealthy diets have increased inflammation in their bodies,” said Dr. Timothy Yeatman, a renowned physician-scientist and professor of surgery in the USF Health Morsani College of Medicine and associate center director for Translational Research and Innovation at the TGH Cancer Institute. “We now see this inflammation in the colon tumors themselves, and cancer is like a chronic wound that won’t heal – if your body is living off of daily ultra-processed foods, its ability to heal that wound decreases due to the inflammation and suppression of the immune system that ultimately allows the cancer to grow.”

According to Yeatman, the findings emphasize the urgent need to reevaluate the components of the Western diet, which typically consists of excessive consumption of added sugars, saturated fats, ultra-processed foods, chemicals and inflammatory seed oils. In previous studies, the USF Health Heart Institute found an imbalanced diet not only impacts colorectal cancer, but also plays a role in other diseases, including Alzheimer’s, diabetes and cardiovascular conditions.

“Our bodies are designed to actively resolve inflammation through bioactive lipid compounds derived from the healthy fats, like avocados, that we consume,” said Ganesh Halade, associate professor in the USF Health Heart Institute and a member of the Cancer Biology Program at TGH Cancer Institute. “Bioactive lipids are very small molecules derived from the foods that we eat and, if the molecules are coming from processed food products, they directly imbalance the immune system and drive chronic inflammation.”

While the molecules are difficult to detect, Halade used a highly sensitive analytical technique to identify trace amounts of lipids in 162 tumor samples from patients at Tampa General Hospital. The tumors were frozen within 30 minutes of removal and transported to his lab via USF and TGH Cancer Institute's Biobank, in collaboration with USF Health Colorectal Surgery and the Gastrointestinal Oncology Program at TGH Cancer Institute.

Inside the tumors, the team observed an excess number of molecules that promote inflammation and a shortage of those that help resolve it and promote healing. These findings pave the way for a new, natural approach -- resolution medicine -- which focuses on restoring balance in the patient’s diet to treat colorectal cancer more effectively.

“A human’s immune system can be extremely powerful and drastically impact the tumor microenvironment, which is great if harnessed correctly for health and wellness,” Yeatman said. “But not if it’s suppressed by inflammatory lipids from processed foods.”

Resolution medicine would focus on reversing inflammation using healthy, unprocessed foods rich with omega-3 fatty acids and derivatives of fish oil called “specialized pro-resolving mediators,” to restore the body’s healing mechanisms along with balanced sleep and exercise.

“This has the potential to revolutionize cancer treatment, moving beyond drugs to harness natural healing processes,” Yeatman said. “It’s a vital step toward addressing chronic inflammation and preventing diseases before they start.”

Early trials using specialized derivatives of fish oil have shown promise in addressing inflammation at its root cause. The trials are underway at TGH Cancer Institute and the team will continue studying resolution medicine and its impact on patient treatment and disease prevention.

Examples of healthy, unprocessed foods: crab, salmon, halibut, spinach, brussels sprouts, seaweed, algae and grass-fed, pasture-raised meats, etc.

Examples of ultra-processed foods: ice cream, sausages, chips, mass-produced bread, breakfast cereals, doughnuts, carbonated drinks, instant soups, some alcoholic drinks, etc.

This research was performed in collaboration with national and international partners at Moffitt Cancer Center, Buck Institute for Research on Aging in California, Vanderbilt University Medical Center in Nashville, Merck Research Laboratories in Boston, Florida Digestive Health Specialists in Bradenton and Hokkaido University in Japan.

PHOTOS Ganesh Halade and Timothy Yeat [IMAGE] | EurekAlert! Science News Releases

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About the University of South Florida

The University of South Florida, a high-impact research university dedicated to student success and committed to community engagement, generates an annual economic impact of more than $6 billion. Across campuses in Tampa, St. Petersburg, Sarasota-Manatee and USF Health, USF serves approximately 50,000 students who represent nearly 150 different countries. U.S. News & World Report has ranked USF as one of the nation’s top 50 public universities for six consecutive years and, for the second straight year, as the best value university in Florida. In 2023, USF became the first public university in Florida in nearly 40 years to be invited to join the Association of American Universities, a group of the leading 3% of universities in the United States and Canada. With an all-time high of $692 million in research funding in 2023 and a ranking as a top 15 public university for producing new U.S. patents, USF is a leader in solving global problems and improving lives. USF is a member of the American Athletic Conference. Learn more at  www.usf.edu

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Journal

Gut

Method of Research

Observational study

Subject of Research

People

Article Title

Integration of lipidomics with targeted, single cell, and spatial transcriptomics defines an unresolved pro-inflammatory state in colon cancer

Article Publication Date

10-Dec-2024