The American grocery store is a place where a bevy of food, drink and sundries are at shoppers’ fingertips.
But researchers with the Network Science Institute at Northeastern University have found that despite the abundance of food options available on grocery shelves most contain processed or ultra-processed ingredients.
Northeastern researchers analyzed ingredient lists of food available online from Target, Whole Foods and Walmart. The results were collected in GroceryDB, an online database of over 50,000 foods and it is searchable on the website Truefood. The study reveals the degree of food processing, empowering consumers to make informed choices.
“Food labels omit key information: whether a product is natural, processed or ultra processed,” says Albert-Laszlo Barabasi, the Robert Gray Dodge professor of network science and a distinguished university professor at Northeastern. “Inspired by mounting evidence that food processing affects our health, we set out to change that.”
The study is the latest in a series of research projects that use artificial intelligence tools to identify ultra-processed foods in the American diet and understand their health implications.
Researchers first used machine learning to develop an algorithm that could identify ultra-processed foods by analyzing patterns of concentrations of different nutrients in food. The algorithm assigned a score — which researchers called FPro — to classify the amount of processing that an individual food has undergone. The higher the FPro, the more processed the food.
The system found that 70% of the country’s food supply is “ultra-processed,” and thus is linked to a higher risk of developing a range of health issues. The algorithm was validated using population studies.
Researchers next used the algorithm to analyze ingredient lists of food available online from Target, Whole Foods and Walmart. The results were aggregated in GroceryDB and made available on Truefood.
For the latest study, published this week in the journal Nature Food, the wealth of data collected allowed researchers to study the availability, and categories, of foods with varying degrees of processing and their price range.
“It’s the first time we’re able to extensively quantify the availability of choices in American grocery stores,” says Giulia Menichetti, an affiliated faculty with the Network Science Institute at Northeastern University.
“You can have the perception of having a lot of options when you go to the grocery stores because you have 10,000 brands,” says Menichetti, also an investigator at Brigham and Women’s Hospital in Boston and a faculty member at Harvard Medical School. “But the reality is that what matters the most is not the number of brands, but the variability of the nutritional properties that these brands have.”
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Menichetti and researcher Babak Ravandi, also of the Network Science Institute, found that Target, Whole Foods and Walmart contain mostly ultra-processed foods and only “a small fraction” of minimally-processed foods.
But there are differences among the stores in terms of the options they offer.
For instance, overall, WholeFoods offers more minimally-processed and fewer ultra-processed items compared with a “particularly high fraction” of ultra-processed offerings at Target, researchers found.
The researchers were also able to evaluate the degrees of food processing in different food categories.
Jerky, popcorn, chips, bread, biscuits and macaroni and cheese options had similar FPro scores, indicating that there are limited choices if you are shopping based on the amount of processing involved, researchers said.
On the other hand, a shopper could choose among a wider array of options from a food processing perspective if they were looking at cereals, milk and milk substitutes, pasta and snack bars, according to the research.
So, what may be driving the decision to select foods that have higher amounts of processing?
One suggestion is price.
Researchers found that among all categories in their database, a 10% decrease in FPro score results in an 8.7% decrease in the price per calorie of the product.
This relationship is even more pronounced in specific food categories.
Among soups and stews, the price per calorie drops by 24.3% per 10% increase in FPro, for instance. This means that the most processed soups and stews are, on average, 66.87% cheaper per calories than minimally-processed alternatives.
In contrast, cereals’ price per calorie drops only by 1.2% per 10% increase in FPro.
Interestingly, there is at least one food category that does not follow this trend.
For milk and milk-substitutes, higher processing yields higher prices — which researchers partially attribute to the higher price of plant-based milk substitutes that require more processing than dairy-based milks.
The network scientists say that research and related tools can help consumers better identify the degree of processing in their foods and make better informed choices. They add that grocery stores can also benefit by evaluating their offerings and stressing more natural or minimally-processed foods.
“You don’t only have the right to food, you have the right to nutritious food,” Menichetti says. “So, accordingly, we need to start tracking and quantifying the quality of food.”