Ultra-processed foods – demonized for years for their supposed effect on our waistlines – don’t actually make people fat, a bombshell report has found.
The US government’s top dietitians found “limited” evidence that these foods cause people to gain weight faster than any other food, after reviewing more than a dozen studies from the 1990s.
The report has not been released in full and alone segments have been uploaded online.
But the excerpts suggest that there is nothing intrinsic to processed food that causes obesity and that the number of calories one eats is the most important factor in weight gain.
People have been hearing a lot lately about the health risks of ultra-processed foods, which may make this report surprising, Carolyn Williams, a registered dietitian who was not involved in the review, told DailyMail.com.
Previous studies have linked ultra-processed foods to cancer, diabetes, mental illness and obesity. According to the new report, the evidence that the foods cause obesity is inconclusive.
The report comes from the U.S. Dietary Guidelines Advisory Committee (DGAC), whose findings form the basis for nutrition labels and public health recommendations for foods.
“What they’re saying is not that there isn’t a link between ultra-processed foods and larger body size or more body fat,” Dr. Williams to DailyMail.com.
“They say we don’t have enough conclusive research right now to say avoid all ultra-processed foods.”
This report comes from a group of 20 nutritionists from across the country chosen by the Department of Health and Human Services and the U.S. Department of Agriculture to create new national dietary recommendations. T
The current group has met to make recommendations on what Americans should eat between 2025 and 2030. This report will likely inform their new guidelines.
They recommend that more research needs to be done before they can make rules about ultra-processed foods.
The report has yet to go live online, but two slides were shared in a screenshot from Kevin D Hall, a nutrition scientist at the National Institutes of Health, in an X post.
In their report, the DGCA said they had “serious concerns” about bias in the studies linking ultra-processed foods to weight gain.
This is mainly because the definition of ultra-processed food is not an exact science, meaning the studies may be subject to ‘misclassification bias’.
This means that studies that use variables that are difficult to categorize can lead researchers to draw inaccurate conclusions.
There is a system for classifying ultra-processed foods called NOVA, which was developed by Brazilian scientists who first started looking into the subject in the 1990s. But there is a lot of “room for interpretation” in these guidelines, Dr. Williams said.
If a food contains ingredients you wouldn’t use at home (additives and stabilizers with long names, for example), it’s probably an ultra-processed product.
This system does not classify foods based on their nutritional value.
For example, mountain dew is ultra-processed, which has virtually no nutritional benefit, but so are many brands of multigrain bread, which contains fiber, vitamins and even some protein.
This, nutritionists like Dr. Williams said, calls into question the validity of ultra-processed foods as a label.
Dr. Carolyn O’Connor, an epidemiologist from Texas A&M who previously worked at the Department of Agriculture and the National Institutes of Health, told The New York Times that certain types of UPFs are much more harmful than others, so grouping them all together makes the measure a lot less accurate.
Ultra-processed foods are the kind of brightly packaged, aggressively marketed foods and drinks that fill our supermarket shelves (stock photo)
‘Unfortunately this is true. Until we have one definition of ultra-processed, the body of evidence will not provide a clear answer,” said Connie Diekman, a registered dietitian practicing in Missouri. said in an X respond to the DGAC’s findings.
Another problem that the DGAC appears to be facing is that many of the studies they found robust enough to include in their review took place in other countries and only one study was conducted in a laboratory.
Without laboratory research on a specific topic, it is difficult for scientists to conclude that ultra-processed foods definitely cause health problems.
Some commentators are hitting back at the report, saying it doesn’t address many of the other concerns people have about processed foods.
Ultra-processed foods have been linked to type 2 diabetes, heart disease and mental health problems, a 2024 study by Australian researchers Deakin University found.
The review looked at older studies – which totaled around 10 million people – and concluded that ultra-processed foods could be linked to a number of poor health outcomes.
This study was valuable and reinforced the belief of nutritionist Josiemer Mattei of the Harvard TH Chan School of Public Health that ultra-processed foods could be a serious problem, told The NYT.
The report also does not appear to address concerns that these foods have been linked to cancer.
A 2023 study from Imperial College London found that the more ultra-processed foods people reported eating, the more likely they were to develop all types of cancer.
Eating very sugary and fatty foods could dampen the influence of our genes that protect against cancer, according to a 2024 report from researchers in Singapore.
It’s understandable that people might read this portion of the DGAC report and react angrily, Dr. Williams said. It doesn’t seem consistent with what most people have heard lately, but it reflects how science works, she said.
According to her, and many other dietitians, these foods have likely contributed to some of the public health problems we’ve seen in the US. But science is a slow process and the world of research isn’t “finally there yet,” she said.
The report only emphasizes that ultra-processed foods require further investigation.
She added, “This is really what you want. You don’t want your federal commission to draw premature conclusions.’