Dec. 20, 2023 -- Figuring out why ultra-processed foods (UPFs) are linked to more chronic health conditions like heart disease and obesity remains an important puzzle for nutrition experts to figure out. When they do, the worst offenders could be taxed or regulated by the government while other UPFs that people enjoy could be reformulated to make them less of a long-term threat to health.
In the meantime, Americans can select healthier options, enjoy riskier foods in moderation, and remember that social gatherings are often high in UPFs. Also, be aware that some foods are tricky – like whole-grain supermarket bread, cauliflower crust pizza, and some breakfast cereals that sound healthier but actually count as ultra-processed foods.
“The other one that is always surprising to me is ketchup,” said Josiemer Mattei, PhD, MPH, the Donald and Sue Pritzker Associate Professor of Nutrition at the Harvard T.H. Chan School of Public Health in Boston. Yes, ketchup contains tomatoes, “but it’s actually a processed food.”
Almost everyone has their "guilty pleasure" or comfort food, including Mattei and the other experts who recently spoke during a webinar sponsored by the T.H. Chan School. Mattei, for instance, said she does not want to give up processed coffee creamers.
Kevin Hall, PhD, senior investigator at the National Institute of Diabetes and Digestive and Kidney Diseases, brings ready-to-heat microwavable meals to work because they are convenient. Even though the nutritional profile of many meals list whole grains, vegetables, and legumes, most of these are classified as ultra-processed foods. “I still consume these foods on a daily basis at work, and I choose ones that I think are probably not so bad for me.”
UPFs Are Ubiquitous
It’s likely unrealistic to ask everyone to give up their favorite UPFs. One reason, “surprising or not surprising, is ultra-processed food encompasses almost 60% of the calories in the American diet today, which is concerning,” said webinar moderator Larissa Zimberoff, a freelance journalist and author of Technically Food: Inside Silicon Valley’s Mission to Change What We Eat.
Experts say it’s not just a story of excess calories, salt, sugar, or some other ingredient in UPFs that link them to worse health over time. NIH research, for example, shows people offered a diet high in UPFs will eat about 500 more calories a day compared to people offered diets without UPFs, but again no one is sure why.
Clearly, something else is going on.
“What is it about a diet that's high in ultra-processed foods that causes people to consume excess calories, gain weight, gain body fat, and presumably over longer periods of time potentially develop obesity and a variety of downstream metabolic consequences?” Hall asked. “We still don't know the mechanism … but we have a whole bunch of ideas about what the mechanism might be.”
An Enigma Wrapped in a Microwavable Burrito
One leading theory is that UPFs are just higher-density foods. Another theory is UPFs may be higher in "nutrient pairs" like sugar and fat, salt and fat, or salt and carbohydrates.
“It's those pairs that seem to potentially drive increase motivation to consume excess calories, at least in some other studies,” Hall said.
“We need a lot more information,” agreed Jerry Mande, MPH, the CEO of the nonprofit Nourish Science and an adjunct professor of nutrition at the T.H. Chan School. “We should know exactly what it is about ultra-processed food … so we can, as consumers, make better choices.”
So while researchers search for the UPFs causing the most damage, one thing is widely accepted: It’s the total amount of UPFs in someone’s diet that makes a difference. Evidence points to “higher consumption and higher intake of UPFs overall being associated with higher risk of eventually developing diabetes,” Mattei said. Emerging evidence also points to higher risk of heart disease. Research also is pretty consistent that artificial- and sugar-sweetened beverages and animal-based products, specifically processed meats, can increase risk for diabetes and heart disease.
Fighting Food Inequality
Addressing food inequality is very important aspect of minimizing the dangers of UPFs, said Mande, who has worked in the FDA and USDA during his career. Food as medicine and other initiatives “have to be delivered equitably. We have populations that might not have access or might be targeted for consuming UPFs at a higher rate because of marketing.”
Addressing nutrition equality is important, and so is designing programs that respect cultural differences and that help eliminate structural and economic barriers to healthy eating.
“Unless you're in a position of real privilege in this environment where, again, almost 60% of the food environment is ultra-processed, avoiding ultra-processed food is extraordinarily difficult,” Hall said. “I don't know any people … with their backyard garden and their personal chef who can prepare all those foods from scratch on a day-to-day basis.”
“For the rest of us” he continued, “we need to use what knowledge we already have to choose what we think are probably the healthiest versions of the tasty, convenient, affordable foods that that we can incorporate into our day-to-day life.”
The goal is not to "throw the baby out with the bathwater," Hall said. Many UPFs are popular because they are tasty, inexpensive, and do not require a lot of time or equipment to prepare.
“They're what a lot of families rely on just to kind of make ends meet and make their families happy at the end of the day," he said. "So we need to know which foods that can be re-engineered in a way that can make them healthier for us.”
