Colorectal cancer among adults 50 and younger has increased over the past three decades. Although the disease is still rare among younger adults, researchers question whether the spike is related to the growing popularity of ultra-processed foods (UPFs).
Scientists are paying more attention to UPF and their findings are becoming mainstream. A study in cellular metabolism, for example, made headlines after researchers found that participants lost weight after two weeks of eating minimally processed foodsonly to get it back when they switched to UPF for two weeks.
The attention surrounding UPFs has helped educate the public about why they are unhealthy. But more than half of Americans don’t even know what qualifies as UPF. The problem is that scientists don’t agree on the answer.
Ultra processed foods
Among nutrition researchers, there is no single way to define UPF. 2021 survey Trends in Food Science and Technology reviewed 470 scientific papers and found 146 definitions of what it means to be “minimally processed”.
NOVA Food Classification
Many researchers follow NOVA classification system developed by a Brazilian research group. NOVA has four categories, placing foods on a spectrum from freshest to most processed.
1. NOVA1 consists of unprocessed and minimally processed foods. This group includes all fresh fruits and vegetables, milk, eggs, meat, rice and whole grains.
2. NOVA2 usually includes ingredients one would keep in one’s fridge or pantry – butter, lard, oil, salt and sugar.
3. NOVA3 is for processed foods. Canned tuna, for example, is fresh fish preserved in oil. Canned beans, frozen fruits and vegetables also fit into this category. Wine, beer and bacon are in group three.
4. NOVA4 is reserved for UPF. Most ready-to-eat foods fall into this category, including candy, cookies, and crackers. Soda is also a Category 4 product.
Read more: The paradoxical antinutrients in our produce
Confusion of food categories
Categorizing food types can be confusing. Where will the bread and cheese go, for example? Fresh bread and cheese will enter the third group. Crumbled cheese and sliced bread will be in the fourth group.
And what about the pasta? It depends on the specific item. Fresh pasta made at home with an old manual pasta machine would be first class. However, most dried pasta would also be considered minimally processed and in the same category. Pre-made, microwave-ready pasta would be category four.
Most people wouldn’t be surprised that Chef Boyardee Beefaroni is a Category Four item. But not all category placements are clear. For example, maple syrup and honey are items you might expect in the first category. But they go through processing, which puts them in the second category.
It’s not just users who can feel confused by the categories. Researchers have also struggled to sort groceries into NOVA categories.
Read more: What science says about the weight-loss potential of the one-meal-a-day diet
Duplication of definitions
Although NOVA is widely used, some researchers are concerned that it is too subjective. In a 2022 article in European Journal of Clinical Nutrition, the researchers tried to see if the participants could find a consensus between which items belonged to which categories. Spoiler alert – they couldn’t agree.
The researchers recruited “assessors” who were health and scientific professionals in France with at least a basic knowledge of nutrition. Raters worked alone and were given 120 branded or 111 generic foods and asked to place them into one of four NOVA categories.
The researchers found the process too subjective and open to interpretation. Orange juice, for example, placed in all four categories. More than 70 percent of raters labeled it a NOVA3 or NOVA4. But 26 percent of raters coded it as minimally or lightly processed.
The study did not specify whether the OJ is the low-ingredient Whole Foods organic version or the French equivalent of Sunny D, made from water and high-fructose corn syrup. Both types are labeled as “orange juice” and demonstrate how each product’s ingredients and production process should be considered in the NOVA classification system.
The study also found that descriptions of NOVA were often confusing. Yogurt, for example, is listed in the official descriptions as a category one item. However, fermented products are categorized under NOVA3, and some programmers believe that because yogurt goes through a non-alcoholic fermentation process, it belongs with other processed foods.
Read more: 4 science-based diets to improve your health
Processed food overload
Although scientists don’t fully agree on how to define or categorize UPFs, they do agree that Americans eat too many of them. 2021 survey in nutrients found that 80 percent of calorie intake in America and Canada comes from UPFs.
The majority of UPF calorie consumption comes from soda and, as the study authors eloquently put it, “confectionery.” Their analysis found that the more UPF a person ate, the less real food they consumed. A higher UPF intake is associated with an increase in the amount of sugar and fat a person eats. It is also associated with a decrease in fiber, protein and important minerals such as magnesium, niacin, potassium, zinc and vitamins A, B12, C, D and E.
Researchers also agree that UPFs are a driving force gaining weight and that people with a diet high in processed foods are prone to to overeat and have a higher caloric intake.
People who are ready to ditch the Pop-Tarts and opt for minimally processed meals may want to consider the mediterranean diet, who prefers fruits, nuts, healthy oils, vegetables and whole grains. And in moderation, it also includes NOVA3 products such as wine, beer and bacon.
Read more: The benefits of eating a plant-based diet