The Surprising Side of Ultra-Processed Foods: What You Didn’t Know

By Jiri Kaloc

Processed meat, fizzy drinks, cereals, packaged snacks, and pre-made meals all belong under the umbrella term ultra-processed foods. We know these can promote overeating and weight gain because they are rich in calories and very pleasurable to eat. However, new research shows that these foods pose yet another unique challenge for people. Let’s take a look at what it is and what should we do about it.

Are ultra-processed foods the new silent killer?

Just like high blood pressure and diabetes, ultra-processed food may have to be added to the list of silent killers. The evidence is mounting that these foods are a contributor to avoidable morbidity and mortality. A landmark study from 2019 showed that ultra-processed diets cause excess calorie intake and weight gain. More studies followed, showing thenegative effects of these foods, including on mental health.

We wrote about a study from 2022 that found that people who consumed the most ultra-processed foods had more depressive symptoms and anxious days. Some of the authors from Florida Atlantic University who worked on this study published a new paper in early 2024 that discusses the mechanisms of how ultra-processed foods are harmful.

Novel ingredients cause problems

The authors of this new study point their fingers to the ingredients that are commonly used in ultra-processed foods: things such as oils, sugars, starch, sodium, and emulsifiers such as carrageenan, mono- and diglycerides, carboxymethylcellulose, polysorbate and soy lecithin. They say that these ingredients are causing us harm because they are novel and there are too many of them in our diet. Hundreds of these additives are now found in nearly 60% of the average adult’s diet and nearly 70% of children’s diets in the USA.

“Those of us practising medicine in the U.S. today find ourselves in a unique position – we are the first cohort of health care professionals to have presided over a decline in life expectancy in 100 years. When we look at the increasing rates of non-communicable diseases in less developed nations, we can see a tracking of this increase along with increasing consumption of ultra-processed foods in their diets,” said Dawn H. Sherling, M.D., corresponding author.

Junk food
Are ultra-processed foods the new silent killer? © Profimedia

How are whole foods better?

The authors say that whole foods that are minimally processed are naturally healthier because of the way we digest and absorb them.

“When the components of a food are contained within a natural, whole food matrix, they are digested more slowly and more inefficiently, resulting in less calorie extraction, lower glycaemic loads in general, and lower rise in triglyceride-rich lipoproteins after eating, which could result in atherosclerotic plaque. Therefore, even if the troublesome additives were removed from the ultra-processed food, there would still be a concern for an over-consumption of these products possibly leading to obesity, diabetes and heart disease,” said Allison H. Ferris, M.D., senior author.

Additives influence our digestive tract and microbiome

Emulsifiers and other additives that move through the gastrointestinal tract mostly undigested could be behind the harmful effects of ultra-processed foods. They may act as a food source for our microbiota, and create a microbiome that can promote disease in some people.

“Additives, such as maltodextrin, may promote a mucous layer that is friendly to certain species of bacteria that are found in greater abundance in patients with inflammatory bowel disease. When the mucous layer is not properly maintained, the epithelial cell layer may become vulnerable to injury, as has been shown in feeding studies using carrageenan in humans and other studies in mice models, using polysorbate-80 and cellulose gum, triggering immunologic responses in the host,” said Dawn H. Sherling.

The authors say we still need more research to better understand how much are ultra-processed foods contributing to rising rates of non-communicable disease. But they urge healthcare professionals to promote whole food consumption.

“In the meantime, we believe it is incumbent upon all health care professionals to discuss the benefits of increasing consumption of whole foods and reducing consumption of ultra-processed foods with their patients,” said Charles H. Hennekens, M.D., co-author.