Why are lower income Americans eating more snacks?
A geographically diverse sample of adults living in neighborhoods of low socioeconomic status (NSES) – and more specifically, in areas with fewer local food stores (supermarkets, supercenters, convenience stores, fruit and vegetable markets, etc) – found a higher intake of snacks and sweets than those in higher-income areas and in neighborhoods with many food stores.
While the past two decades has seen a lot of research in this area, researchers from the University of Michigan and University of Alabama-Birmingham maintain there is inconsistent evidence regarding the role of objectively-measured food environments on dietary behavior across socioeconomic groups.
Food deserts
A USDA-defined food desert is a geographic area where residents have limited access to affordable and nutritious food. Specifically an urban area where at least 500 people (or 33% of the population) reside more than one mile from a supermarket or large grocery store. This is ramped up to more than 10 miles from a supermarket for the rural area measurement.
These areas must have a poverty rate of 20% or higher. Alternatively, the average family income must be at or below 80% of those across the metropolitan area or state.
Studies have applied a range of methods for characterizing food store availability – from the well-known US Department of Agriculture’s ‘food desert’ measure to methods like sausage buffers – which has resulted in mixed quantitative evidence.
The researchers also said past research has been limited to select cities and specific store types and focused exclusively on fruit and vegetable consumption or on overall diet quality. Far less is known about the intake of snacks and sweets.
Consumption of these foods remains high amongst Americans, despite the consistent pressure by health watchdogs like the American Heart Association to encourage citizens to reduce their sugar and salt intake.
The current study was designed to fill that information gap, examining the association of food store availability and NSES with the total intake of sweets and snacks. The study also broke down the category into four subcategories, including bakery sweets; candy and desserts; savory snacks and crackers; and nutrition bars and low-fat snacks and sweets.
Key findings
Living in a USDA-defined food desert was not associated with intake, regardless of race or income.
Middle and older aged Americans who live in neighborhoods with a higher density of sfood stores ate 9% fewer snacks and sweets overall. There was also 10% fewer sweet bakery and 6% fewer candy and desserts sales than people in NSES without local food stores.
People in the highest income areas ate 11% fewer snacks and sweets overall, 19% fewer bakery products and 6% fewer savory snacks and crackers.
Higher-income households ate more nutrition bars and low-fat snacks and sweets compared to lower-income households.
The study did not conclude a causal relationship between income and neighborhood food store availability and snack consumption.
'Unjustly exposed to greater targeted marketing'
Lead author Ian-Marshall Lang, research project manager at U-M’s Environment and Policy Laboratory, hypothesized that people in neighborhoods without food stores typically buy more shelf-stable foods – which obviously include treats like snacks and sweets. He also believes they frequent less traditional food stores like dollar stores, which carry fewer healthy options.
Sausage bufffers
To understand environmental contexts of populations, researchers have for the past two decades often used ‘buffers’ of a certain distance around key environments such as homes, schools, work sites and parks. Straight line buffers (also called circular, crow flies or airline buffers) simply go out a certain distance in a straight line from the facility or place, creating a circle.
While results using sausage buffers are similar to those using other buffering techniques, the sausage buffer approach can be replicated across various software programs, allowing for greater independence from specific software.
However, the sausage buffering approach does not solve all problems related to physical activity and food environments, the most acute being that pedestrians and cyclists do not always move along the street network.
More importantly, he contended, “Our neighborhood income findings may be explained by previous research showing lower-income areas are unjustly exposed to greater targeted marketing for snacks and sweets, higher prices for healthy food, fewer healthy food options in stores and greater stress.”
Added Lang, “Surprisingly, the study found that people living in USDA-defined food deserts ate the same number of snacks and sweets as people who did not live in food deserts.
“This could be because the USDA defines food stores as large supermarkets (for example, Walmart, Meijer), whereas our study defines primary food stores as places where 94% of US households do the majority of their food shopping, regardless of income.”
These include supermarkets, supercenters and select food retailers (small grocery stores, fruit and vegetable markets, bakeries, convenience stores and drug stores).
“In identifying potential settings for future programming and interventions that target snacks and sweets intake, it may be important to consider places devoid of primary food retailers rather than places only devoid of large traditional supermarkets,” Lang said.
What do these numbers mean in terms of America’s healthy food choices?
“Though we didn’t look at the health impacts of snacks and sweets consumption in this paper, we do know from previous research that consumption of snacks and sweets like the ones examined in this study is associated with higher calorie intake and body weight in adults,” said Lang.
“We also know that making even small, positive dietary changes – like swapping a one calorie-dense snack or sweet for a more nutrient-dense snack like fresh fruit – can have benefits for population health.”
Methodology
The cross-sectional study used data from 21,204 participants in the ongoing REasons for Geographic And Racial Differences in Stroke study, sponsored by the National Institutes of Health (NIH).
What We Eat in America food group categorizations guided outcome classification into one main category (total snacks and sweets) and four subcategories (savory snacks and crackers; sweet bakery products; candy and desserts; nutrition bars and low-fat snacks and sweets).
NSES and food store availability were determined using geographic information systems.
Food store availability was characterized as geographic access to primary food stores (for example, supermarkets, supercenters and select food retailers) in urbanicity/rurality-tailored neighborhood-based buffers.
Multiple linear regression was used to predict each outcome.
Studies:
Intake of Snacks and Sweets in a National Study of Built and Social Environments: the REasons for Geographic And Racial Differences in Stroke Study’
Authors: Ian-Marshall Lang, Cathy L Antonakos, et al
The Journal of Nutrition (2024), available online, Article In Press
https://doi.org/10.1016/j.tjnut.2024.05.017
Creating a replicable, valid cross-platform buffering technique: The sausage network buffer for measuring food and physical activity built environments
Authors: Forsyth, A., Van Riper, D., Larson, N. et al
Int J Health Geogr 11, 14 (2012)
https://doi.org/10.1186/1476-072X-11-14
The reasons for geographic and racial differences in stroke study: objectives and design
Authors: Virginia J Howard, Mary Cushman, Leavonne Pulley, et al
Neuroepidemiology, 2005;25(3):135-43
