Although Americans continue to buy most of their packaged foods at traditional grocery stores, they are increasingly shopping for such products at convenience stores (such as 7-Eleven and CVS), mass merchandisers (such as Target and Walmart), and warehouse clubs (such as Sam’s Club and Costco), according to a recent study published in the American Journal of Preventive Medicine.
That trend raises a potential public health concern, say the University of North Carolina researchers who conducted the study. For their research also found that the packaged foods people are buying at places other than grocery stores tend to be significantly less nutritious, containing much more sugar, sodium and saturated fat.
Yes, yes, this finding — particularly in regard to convenience stores — may seem obvious. But as the researchers point out in their study, very little actual data exists on the types of stores where people shop for packaged foods, what they buy when they get there, and the nutrient profile of those purchases.
Where people buy packaged foods (defined as any food with a barcode) is important, as such items make up 78 percent of the average American’s store-bought food.
Study details and key findings
The data for this new study came from thousands of Nielson Homescan participants who used barcode scanners to report all their purchases. The data was collected from 2000 to 2012. Participants also reported where they had shopped. The researchers then used the barcodes to determine the specific items that were bought — and their nutritional content.
Over the 12-year course of the study, the percentage of packaged foods bought by the Nielson Homescan households from non-grocery stores rose about 60 percent at each type of store — from 13.2 percent to 23.9 percent at mass merchandisers, from 3.6 percent to 5.9 at warehouse clubs, and from 6.2 percent to 9.8 percent at convenience stores.
The percentage of packaged foods bought from grocery stores during that same period decreased by more than 12 percent, from 58.5 percent to 46.3 percent.
Throughout the study, most of the calories in the packaged food purchased at all the stores — including the grocery stores — came from junk foods: savory snacks (such as potato chips, tortilla chips and crackers), grain-based desserts and snacks (such as cookies, doughnuts and granola bars), and fruit drinks and regular soft drinks.
But, overall, the packaged foods bought at grocery stores consistently had fewer calories than those bought elsewhere. They also tended to be packed with more nutrients.
Not surprisingly, perhaps, the packaged foods bought at convenience stores had the most sugar. In fact, more than a third of all calories purchased at those stores came from just two types of products: gum and candy.
The food purchased at the warehouse clubs had the most sodium.
A third of the beverage calories purchased at convenience stores and mass merchandisers came from soft drinks or fruit drinks.
Limitations and implications
The study comes with several caveats. For example, the researchers had no way of determining how much choice the participants had in where they shopped. In addition, the people in the study may not have scanned every item they purchased — especially ones bought “on the go.” And the scanners did not capture non-store sources of foods, such as those purchased at restaurants.
The researchers also stress that their findings reflect purchases, not diets. No data was collected on how much of the purchased packaged foods was actually consumed.
Still, the study suggests, say its authors, that “food deserts” — neighborhoods with few stores that offer healthy food choices — may not be as big a factor in the obesity epidemic and the rise in nutrition-related chronic diseases as believed.
“It may not be the store type availability that matters,” they write, “but the fact that unhealthy foods/beverages are ubiquitous and are purchased everywhere.”
You can download and read the study in full through the American Journal of Preventive Medicine website.