July 25, 2024 -- As nutrition researchers publish more studies about processed food and health issues, the takeaway seems clear: Processed food isn’t great for you, and the more processed it is, the worse it seems to be for you. At the same time, not all processed food is harmful, and scientists are still trying to understand the specific aspects to avoid.
In the U.S., more than half of energy intake comes from ultra-processed foods, which include a wide range of ready-to-eat products, including packaged snacks, carbonated soft drinks, instant noodles, and packaged meats. In general, the products include additives to help with taste, texture, appearance, and shelf life, and they often contain more calories, salt, sugar, and saturated fat as well as low fiber, nutrients, and vitamins.
In February 2024, researchers from the U.S. and Australia published a study in BMJ based on data from nearly 10 million people, which found associations between ultra-processed food and 32 health domains, including death, cancer, and issues related to the brain, heart, lungs, stomach, and metabolism. They also food links to poor sleep, anxiety, depression, and other mental health disorders.
As processed food consumption increases worldwide — due to convenience, human behaviors, and commercial influences — nutritionists are concerned about the potential impact, both now and decades from now.
Read on to learn more about what the latest studies show.
Ultra-processed Foods May Carry Higher Death Risks
In a study of more than 500,000 U.S. adults, those who ate more ultra-processed food were more likely to die during the next 2 decades than those who ate less processed food. However, they only appeared to be about 10% more likely to die and had a higher likelihood of deaths related to heart disease or diabetes but not cancer, indicating an area with ongoing questions.
In general, soft drinks and highly processed meats — such as hot dogs, sausages, and deli meat — carried some of the strongest risks for death. These associations remained across the board, whether people had a better or worse diet and among those classified as normal weight or having obesity.
Even so, the U.S. food supply and people’s dietary preferences have changed dramatically since the mid-1990s, when the data was first collected. The links between food processing and health risks could be more dramatic and clear now, which calls for further research.
“Our study results support previous studies, which indicate that ultra-processed food intake adversely impacts health and longevity,” said Erikka Loftfield, PhD, MPH, a researcher at the National Cancer Institute who presented the results at the annual American Society for Nutrition meeting in July.
“However, there is still a lot that we don’t know, including what aspects of ultra-processed foods pose potential health risks,” she said.
Processing and Baking Foods Can Break Down Nutrients
Looking at grains in particular, processing makes a significant difference. In refined flours and breads, major minerals — such as calcium, magnesium, phosphorous, and potassium — dropped by 72% when compared with whole wheat, and trace minerals — such as copper, iron, and zinc — fell by 64%. Beyond that, both refined and whole wheat products had less vitamin E and carotenoids (vitamin A-related compounds) than raw wheat kernels.
“Both milling and baking have significant impacts on multiple nutrient levels within wheat flour and bread,” said David Killilea, PhD, a research scientist focused on mineral metabolism at the University of California, San Francisco, who also presented at the ASN meeting.
Although the Dietary Guidelines for Americans recommend whole grains for at least half of total grains consumed, most people don’t meet the suggestion, he said. Aiming for unrefined flours can help, as well as looking at processes that help to preserve vitamin and mineral content in wheat products.
“Whole grains have an important role to play in the nutritional palette of the Western diet,” Killilea said. “Processes that enrich the nutrient density of wheat-based foods should be encouraged.”
Limiting UPFs Doesn't Necessarily Equal a Healthy Diet
Eating only minimally processed foods doesn’t automatically make a meal healthy. Instead, the type of food is likely more important than the processing method. For instance, many packaged foods may be classified as ultraprocessed but have high-quality nutrients, such as unsweetened applesauce, liquid egg whites, and certain brands of packaged produce, including raisins and canned tomatoes. Similarly, plenty of non-processed foods may be considered low-quality.
Researchers compared two menus that reflected a typical Western diet, with one emphasizing minimal processing (20% of calories) and the other emphasizing ultra-processing (67% of calories). They found the less processed menu was more than twice as expensive and expired about three times sooner but didn’t contain any additional nutritional value.
“More-processed and less-processed diets can be equally nutritious (or non-nutritious), but the more-processed diet may have a longer shelf life and be less costly,” said Julie Hess, PhD, a research nutritionist at the USDA-Agricultural Research Service Grand Forks Human Nutrition Research Center in North Dakota. Hess presented the results at the ASN meeting.
In one example, the research team compared a Western breakfast with eggs, potatoes, and bread with jam. In the less-processed meal, the bread and jam were homemade, and the eggs and potatoes were whole and unprocessed, as compared with a more-processed meal with packaged bread, jam, eggs, and tater tots.
“Building a nutritious diet involves more than a consideration of food processing,” Hess said. “The concepts of ultra-processed foods and less-processed foods need to be better characterized by the nutrition research community.”
Making Better Choices Is Key
Small swaps can make a big difference in diet quality and overall health. Sugar-sweetened beverages (such as sodas, fruit drinks, sports drinks, energy drinks, sweetened waters, coffees, and teas with added sugars) top the list of ultraprocessed drinks that should be nixed due to associations with obesity, diabetes, and diseases linked to the heart, kidney, and liver.
Typically, nutritionists recommend water as the best replacement, but other non-sugary options can help, such as unsweetened tea or coffee. Sugar-free options or drinks with other sweeteners (such as stevia or monk fruit) may serve as alternatives, especially while taking steps to consume less sugar.
Processed meats are also named often as the biggest culprits of unhealthy diets due to high calories, low protein, fillers, and preservatives such as nitrates and nitrites. Although it may be easier for some people to ditch bacon or hot dogs, sandwich lovers may find it more difficult to go without deli meat.
In general, it’s a good idea to swap fattier and saltier meats such as bologna and salami for leaner cuts of turkey, chicken, ham, or roast beef. Ask for low-sodium or uncured meat, and try to choose fresh cuts over prepackaged slices.
“Deli meat that is sliced fresh off the bone or slab contains natural nitrates and can be less processed. When possible, buy nitrate-free and low-sodium options,” said Julia Zumpano, a registered dietitian with the Cleveland Clinic.
Opting for other sandwich fillers can help reduce your processed meat intake, especially if you choose eggs, nut butters, natural cheeses, tempeh, tofu, or beans, she said. And if you have the time and ability, making your own sandwich meats is an option, though it may not be possible for everyone.
“You can buy a roast, ham, or chicken breast and cook it yourself, then slice it off into lunch meat size portions,” she said. “This helps to ensure you know what you’re eating.”
When it comes to other ultraprocessed foods, looking at food labels and making little swaps can help. If you aim for less sugar, salt, and saturated fats and focus on increasing fiber, protein, and unsaturated fats, you’ll reduce your health risks and improve your diet quality for healthier living.
