In recent years, ultra-processed foods have been linked to everything from obesity to cancer.
But Jessica Wilson, a registered dietitian in California, is part of a large group of health experts who believe the evidence is not so clear.
She and many others argue that the “ultra-processed” food category is too broad and doesn’t distinguish between products like bread and candy, or almond milk and soda.
Putting his words into practice (literally), Wilson conducted a month-long experiment to measure the effects of a diet dominated by processed foods on his body and mind.
She found that eating this way helped her have more energy, feel fuller for longer, and overall, she said on Instagram, “just feel so much better.”
Ms. Wilson’s diet for one month consisted of 80 percent processed foods, like those pictured above. She said the processed food category is broad and can include items that many Americans rely on for nutrition.
Wilson ate a diet consisting almost exclusively of processed foods for a month, including all the different definitions of ultra-processed foods, including prepackaged meals, frozen meals, takeout meals and foods with more than five ingredients.
Her goal, it seems, was partly to demonstrate that the definition of ultra-processed foods is tenuous, so she consumed things like tofu, oat milk and grain-free granola — which have dozens of ingredients but can be considered healthy — as well as familiar favorites like hot dogs.
“How can this entire category of foods be something we’re supposed to avoid?” asks Ms. Wilson. He told TIME.
While most dietitians have spoken out against processed foods, Ms Wilson is not alone in questioning the confusing guidelines in place.
The most widely recognized way of classifying foods is called NOVA. A good rule of thumb is that if your food contains ingredients you don’t recognize or can’t pronounce, it’s probably processed.
There is a lot of “room for interpretation” in these guidelines, registered dietitian Carolyn Williams previously told DailyMail.com.
For example, mass-produced multigrain bread can be considered ultra-processed, even though it is a good source of fiber, vitamins and other nutrients that most dietitians would recommend including in the diet, Williams said.
Clearly, he explained, multigrain bread is not in the same nutritional category as Mountain Dew, which is also highly processed but lacking in nutrients and high in sugar.
Therefore, not all ultra-processed foods are the same and therefore may not have the same health effects.
To challenge this gap, Ms. Wilson decided to make 80 percent of her diet ultra-processed foods for the month of September 2023, including the usual monsters like pizza and hot dogs, plus vegan cheese, oat milk and grain-free granola.
The remaining 20 percent came from vegetables, fruits, eggs, nuts and seeds.
At the end of the month, the dietitian said she felt better, had more energy, and was not as hungry as usual while eating mostly processed foods.
She noted in a diet summary that a ‘noticeable gap’ had appeared in the leash she uses around her waist to walk her dog during the month, suggesting she had even lost weight.
These results are likely evidence that she had not consumed enough calories before starting the diet, Wilson said. Eating these packaged foods provided her with the amount of calories she needed to get through the day with energy, she suggested.
The NOVA food processing classification system classifies foods into four categories based on their ingredients and manufacturing process. Some dietitians say these guidelines leave room for interpretation.
Still, the popular idea among many dietitians is that processed foods are linked to weight gain and other health problems.
Processed meats containing nitrates (a common additive in many sausages and cold cuts) have been linked to an increased risk of colorectal and stomach cancer, according to MD Anderson Oncologists.
A 2019 study by dietitians at the National Institutes of Health fed 20 people a diet consisting of 80 percent ultra-processed foods for two weeks, and a whole foods diet for two weeks.
The processed breakfast, for example, might include a bagel and turkey bacon, while the unprocessed breakfast might include oatmeal and fruit.
At the end of the study, researchers found that when following the processed plan, people consumed an average of 500 more calories than they would on a whole-foods diet and gained weight as a result.
In one of the best-known studies on processed foods, Dr. Chris van Tullken, a virologist and professor at University College London, ate a diet consisting of 80 percent processed foods for a month.
By the end, he had gained weight, suffered from constipation and, he said, tests showed worrying changes in his hormone levels and brain biology. “Within just a few weeks, I felt like I had aged ten years. I was in pain, exhausted, miserable and angry,” Dr van Tullken wrote in a column for DailyMail.com.
Ms. Wilson said it was possible that both Mr. Van Tullken’s study and her own were true.
In her opinion, it is important to keep in mind that there are many ways to use processed foods, and that making them all seem bad makes it harder for people to get the cost-effective nutrition that some processed foods offer.
She added“Both experiences are real. The public deserves to hear more than one side of the story,” Wilson said.