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Webinar Recap | Harvard T. H. Chan - The dangers of ultra-processed foods

January 5, 2024

Freelance journalist and author Larissa Zimberoff moderates a webinar with three nutrition experts to assess America's love/hate relationship with ultra-processed foods (UPFs). Her guests include NIH NIDDK Senior Investigator Kevin Hall, Harvard T. H. Chan School of Public Health Adjunct Professor Jerry Mande, and Josiemer Mattei, Donald and Sue Pritzker associate professor of nutrition at the Department of Nutrition, Harvard T. H. Chan School of Public Health.

Webinar length: 51 min.

7 Key Takeaways

1. Ultra-processed foods (UPFs) make up 60% of the U.S. food supply, often found in the middle aisles of a grocery store.

UPFs are industrial formulations of relatively inexpensive agricultural inputs, mostly devoid of whole foods, involving extensive processes to refine these ingredients, and using additives typically not used in home kitchens.

UPFs are found at the end of the NOVA classification system which focuses on food processing as a spectrum as follows: Category 1: Minimally processed or unprocessed foods, fresh fruits and vegetables, poultry, eggs; Category 2: Processed culinary ingredients such as sugar, salt, butter, or oils that are not eaten on their own but instead added to Category 1 foods to make dishes; Category 3: Processed foods made by adding Category 2 foods to Category 1 foods; and finally, Category 4: Ultra-processed foods (UPFs).

2. Some UPFs may sound healthy, but surprisingly, still qualify as UPFs.

Foods such as cereals and breads—including whole grain breads—as well as yogurt, ready-to-eat microwaveable meals, and ketchup all count as UPFs as they have ingredients designed to enhance shelf life in the supermarket.

3. Evidence suggests that overall, higher consumption and higher intake of UPFs is associated with higher risk of developing T2DM and CV disease, especially coronary heart disease. A landmark NIH study suggests that the ultra-processing of foods itself is causing Americans to eat more, although the exact mechanism has yet to be identified.

Nutrition experts note that there's consistent evidence for artificial and sugar-sweetened beverages, for animal-based products, specifically for processed meats as having an increased risk for T2DM and CV disease.

A recent study co-authored at Harvard T.H. Chan School of Public Health also found that, despite the attraction of UPFs as "comfort foods," there's an increased risk for depression in consumers eating nine or more servings of UPFs in a day.

One noteworthy NIH trial cited by experts involved comparing two different diets that were matched for salt, sugar, fat, fiber, carbs, and overall glycemic load. Participants spent a month at the NIH clinic, 24 hours a day, seven days a week and were randomized either to a diet that was very high in ultra-processed foods or a diet that had basically no ultra-processed food. Despite the diets being matched for these various nutrients of concern, researchers found that the cohort consuming the UPFs ate about 500 calories per day more over the two weeks that they were on that diet as compared to the minimally processed diet. The ultra-processed cohort gained weight and body fat. The individuals on the minimally processed diet spontaneously lost weight and lost body fat.

However, researchers don't know exactly what it is about a diet that's high in UPFs that causes people to consume excess calories, gain weight, gain body fat, and over longer periods of time potentially develop obesity and other metabolic diseases.

The NIH study has not been replicated. Experts say that there simply isn't enough funding for studies analyzing specific types and groups of UPFs. It's also challenging for researchers to find hospital facilities to house larger groups of study participants vs. only a few individuals at a time.

4. The ultra-processing of foods correlates with the U.S. obesity epidemic: Americans have shorter and more declining life expectancies than the other 20 top developed countries.

America's obesity problem began in the 1990s and accelerated pre-COVID. In the 1990s, there wasn’t a single state in America that had an obesity rate of 15%. Today there’s not a single state with less than 25% and almost half have more than 35%. And overall, as a country, the U.S. is more than 40% obese.

We now know that two-thirds of severe COVID hospitalizations involved individuals with obesity, hypertension, and diabetes—all diet-related diseases.

5. Not all UPFs are equally unhealthy, but there isn't enough evidence for experts to know which ones are the most unhealthy.

If we understood the mechanisms that link UPFs to increased risks for chronic, diet-related diseases, then nutrition experts believe we could reformulate and reengineer these foods so that they don’t cause us to be sick.

Current NIH studies are focusing on two potential mechanisms—the energy density of food and the proportion of so-called hyper-palatable foods, such as foods that are high in both sugar and fat, salt and fat, and salt and carbohydrates—in an attempt to try to understand the drivers that cause people to overconsume calories on diets that are high in UPFs.

6. There are currently no incentives for UPF manufacturers to change their practices; consumers will likely continue to use UPFs as they are accessible, affordable, and convenient; health experts are looking to "food as medicine" programs and also considering taxing certain UPFs.

The FDA already has the historical authority to regulate these UPFs, but some experts say that the agency is more focused on preventing acute infections such as salmonella outbreaks than on preventing chronic diseases.

"Food as medicine" programs are new initiatives that clinics are using to prevent disease and educate their patients about nutrition. These include prescription programs where patients get prescribed a box or an amount of covered healthy meals for a particular condition, or for general prevention. However, ensuring equitable delivery of such programs to all Americans continues to be a challenge.

The number one purchased food with the SNAP food stamp program is soft drinks. A heftier sales tax on sodas might reduce consumption of this UPF, one that has been confirmed to lead to adverse health outcomes. Similar taxes on cigarettes were successful in reducing tobacco smoking in teenagers.

7. There needs to be more investment in science so that we know what it is about our food that's making us so sick.

According to National Institute of Diabetes & Digestive & Kidney Diseases Senior Investigator Kevin Hall, there's an urgent need for funding for more studies: "We have this mountain of epidemiological data now that links diets high in ultra-processed foods with a wide variety of chronic diet-related diseases. And we don’t know which are the most problematic foods ..."

Adjunct professor of nutrition at Harvard T.H. Chan School of Public Health, Jerry Mande, notes that increasing funding for UPF research is simply a matter of recognizing the public health urgency of the situation: "When it's important to us like COVID, the U.S. had a vaccine in a year."

Moderator: Larissa Zimberoff; Speakers: Kevin Hall, Jerry Mande, Josiemer Mattei. (2023, December 14). Harvard T.H. Chan School of Public Health. The dangers of ultra-processed foods. https://www.hsph.harvard.edu/event/the-dangers-of-ultra-processed-foods/?utm_source=newsletter&utm_medium=email&utm_content=our%20website&utm_campaign=2023.12.14-