Effect of price, variety, and
caloric cost on food
purchases in corner stores in
NYC
Mindy Chang, MPH, DVM
City Harvest Evaluation Dept.
November 2014
Disclosure
I have no relationships to
declare
2
Introduction
•
Obesity
– 34.9% (78.6 million) U.S. adults are obese1
– Disproportionately affect groups with the highest poverty rates2
– In NYC, 22% are obese3
•
•
Rates of obesity increases as poverty increases4
–
15.7% with highest income are obese
–
26.8% with lowest income are obese
Food environment of low-income neighborhoods
– Predominantly corner stores5
• Charge higher prices for healthier food6
• Limited availability of fruits and vegetables7
• Primarily offer inexpensive snack foods8
– Candy, fried snacks
– Sugar sweetened beverage
– Packaged bakery product
– Presence of corner stores associated with increased risk of
obesity9
3
Introduction
• City Harvest Healthy Corner Store program
– Work with corner stores to encourage
• Expansion of produce sales
• Expansion of healthy choices in stores
• Question: What factors will affect customer
purchases
4
Methods
• Inventory of corner stores (n=29)
– List varieties of produce, potato chips and candy
– List prices of produce, potato chips and candy
– List sizes of potato chips and candy
• Customer surveys (n=437)
– What do you purchase most often from corner
stores
– How far is supermarket, corner store and fast food
restaurant from where you live
– Did you notice food advertisements
• Pictures of ads present in 2 block radius
around corner store
5
Methods
• Data collection
– June 2013 to September 2014
• Inventory of corner stores (n=29)
–
–
–
–
–
Bedford-Stuyvesant (n=11)
South Bronx (n=9)
Long Island City/Astoria (n=4)
Stapleton (n=2)
Washington Heights/Inwood (n=3)
• Customer surveys (n=437)
– Gender
• Female
45%
– Race/ethnicity
• Black
• Hispanic
41%
36%
– Average age
41.3 years old
– Average education level: High school graduate/GED
6
What are customers buying-food
(n=437)
36%
36%
Chips
Candy
32%
24%
9%
Fresh fruit
Fresh vegetable
Canned fruit
8%
Canned vegetable
7
Factors that may affect corner store
purchases
• Distance to stores
– Supermarket
– Corner stores
– Fast food restaurants
• Quality of produce available in corner stores
• Number of varieties available of produce and
snack foods at corner stores
• Cost of produce and snack foods at corner
stores
• Advertising
Factors that may affect purchases:
Distance to stores
Store type
Range of blocks to
store
Average number of blocks
to store (+/- stdev)
Supermarket
0-20
3.17
(+/-3.18)
Corner store
0-8
1.36
(+/-0.98)
Fast food restaurant
0-25
3.36
(+/-3.35)
• Distance to supermarkets, corner stores and
fast food restaurants categorized as
– Close (less than 3 blocks)
– Medium (3 to 6 blocks)
– Far (more than 6 blocks)
Factors that may affect purchases:
Distance to stores
% of Customer who
Purchase Fruits
% of Customers who Purchase
Vegetables
40%
33%
36%
32%
31%
27%
33%
31%
29%
26%
26%
24%
23%
24%
26%
20%
17%
16%
Corner store
Supermarket
Close
Medium
Fast food
restaurant
Far
Corner store
Supermarket
Close
Medium
Fast food
restaurant
Far
Factors that may affect purchases:
Distance to store
% of Customers who
Purchase Chips
% of Customers who Purchase
Candy
42%
42%
38%
36%
42%
38%
33%
36%
32%
33%
27%
21%
20%
0%
Corner store
38%
37%
42%
0%
Supermarket
Close
Medium
Fast food
restaurant
Far
Corner store
Supermarket
Close
Medium
Fast food
restaurant
Far
Factors that may affect purchases:
Quality of produce
• Quality of produce categorized as
– Poor (1)
– Fair (2)
– Good (3)
Average fresh fruit
quality
2.4
Average fresh vegetable
quality
(+/- 0.49)
2.2
(+/- 0.49)
Factors that may affect purchases:
Quality of produce
40%
31%
24%
24%
24%
15%
Fruit quality
% Customers who
purchase fruits
Vegetable quality
Poor
Fair
Good
% Customers who
purchase vegetables
Factors that may affect purchases:
Variety
Food type
Range of variety
Average variety (+/- stdev)
Fruit
0-16
7.18
(+/-3.92)
Vegetable
0-20
9.28
(+/-4.89)
Potato chips
0-46
14.14
(+/-11.64)
Candy
0-165
38.48
(+/-33.57)
• Variety of produce, chips and candy available
categorized as (based on tertile)
– Low variety
– Medium variety
– High variety
Factors that may affect purchases:
Variety
55%
*
43%
37%
*
34%
30% 30%
13%
Fruit
% Customers
who purchase
fruit
*p <0.05
41%
29%
31% 31%
13%
Vegetable
% Customers who
purchase vegetable
Low variety
Potato Chips
% Customers who
purchase chips
Medium variety
High variety
Candy
% Customers who
purchase candy
Factors that may affect purchases:
Cost (per ounce)
Food type
Range of cost per
ounce
Average cost per ounce
(+/- stdev)
Fruit
$0.05-$0.34
$0.12*
(+/-0.04)
Vegetable
$0.04-$0.33
$0.12*
(+/-0.05)
Potato chips
$0.17-$1.00
$0.41
(+/-0.12)
Candy
$0.01-$1.25
$0.47
(+/-0.26)
•
Candy and potato chips are significantly more expensive
– Contradictory to what customers are purchasing
•
Cost per ounce of produce, chips and candy available categorized as (based on
tertile)
– Low cost
– Medium cost
– High cost
*p<0.05 significantly different compared to chips or candy
Factors that may affect purchases:
Cost (per ounce)
50%
43%
45%
40%
35%
34%
41%
37%
36%
32%
30%
28%
26%
23%
25%
20%
15%
17%
14%
10%
7%
5%
0%
Fruit
% Customers
who purchase
fruit
*p <0.05
Vegetable
% Customers who
purchase vegetable
Low cost
Potato Chips
% Customers who
purchase chips
Medium cost
High cost
Candy
% Customers who
purchase candy
Factors that may affect purchases:
Cost (per calorie)
Food type
Range of cost per
calorie
Average cost per calorie
(+/- stdev)
Fruit
0.33¢-7.14¢
1.76¢
(+/-1.233)
Vegetable
0.19¢-3.62¢
1.11¢*
(+/-0.53)
Potato chips
0.11¢-0.65¢
0.27¢
(+/-0.08)
Candy
0.09¢-1.15¢
• $0.0043
+/- 0.0024 per calorie
0.43¢
(+/-0.24)
• Potato chips and candy is significantly cheaper per calorie
• Cost per calorie of produce, chips and candy available
categorized as (based on tertile)
– Low cost
– Medium cost
– High cost
*p<0.05 significantly different compared to chips or candy
Factors that may affect purchasesCost (per calorie)
*
*
39%
37%
35%
41%
38%
36%
33%
*
27%
24%
15%
14%
Fruit
% Customers
who purchase
fruit
*p <0.1
12%
Vegetable
% Customers who
purchase vegetable
Low cost
Potato Chips
% Customers who
purchase chips
Medium cost
High cost
Candy
% Customers who
purchase candy
Factors that may affect purchases:
Advertising
Ads for type of
food
Range of number
of ads seen
Average number of
ads seen
Fruits and
vegetables
0-9
2.71
Fast foods
0-14
5.36
• Number of advertisements of produce and fast foods chips in
neighborhood categorized as (based on tertile)
– Low number of ads
– Medium number of ads
– High number of ads
Factors that may affect purchases:
Advertising
78%
62%
38%
65%
37%
25%
Percent of customers who notice produce Percent of customers who notice fast food
ads
ads
Low number of ads
Medium number of ads
High number of ads
55%
*
25%
27%
22%
24%
25%
Percent of customers who purchased
Percent of customers who purchased chips
produce
Low number of ads
Medium number of ads
High number of ads
Conclusions
• Factors that showed significant association with
customer reported purchases from corner stores
– Number of varieties available
– Cost of produce (per calorie)
• Factors that did not show any significant
association
– Distance to store
– Quality
– Advertising
• Program should focus on availability
– Increasing variety of fruits and vegetables sold
• Work with suppliers, retailers and policy makers
to affect prices
– May be difficult to achieve
Limitations
• Self-report
• Sample size
– 437 customers
– 29 corner stores
• Assessment of quality of produce
– Subjective process
• Number of varieties available of produce
– Seasonality not accounted for
• Cost of produce at corner stores
– Approximation of produce based on average size and calorie
content of produce
• Advertising
– Only print ads present in neighborhood
– May not have captured all ads
– TV commercial ads not accounted for
Works cited
1.
2.
3.
4.
5.
6.
7.
8.
9.
Centers for Disease and Prevention. Overweight and Obesity: Adult Obesity Facts.
Accessed Nov 11, 2014. www.cdc.gov/obesity/data/adult.html
Arfken CL, Houston CA. Obesity in inner-city African Americans. Ethn Healthy. 1996
Dec; 1(4): 317-26.
New York City Department of Health and Mental Hygiene. Obesity. Access Nov 11,
2014. www.nyc.gov/html/doh/html/living/obesity.shtml
New York City Department of Health and Mental Hygiene. Community Health
Survey (2012): public use dataset accessed on Nov 11, 2014.
http://www.nyc.gov/html/doh/html/data/chs-data.shtml
Cannuscio CC, Tappe K, Hillier A, Buttenheim A, Karpyn A, Glanz K. Urban food
environments and residents shopping behaviors. Am J Prev Med. 2013; 45(5):606614.
Krukowski RA, West DS, Harvey-Berino J, Elaine Prewitt T. Neighborhood impact
on healthy food availability and pricing in food stores. J Community Health. 2010;
35: 315-20.
Leone AF, Rigby S, Betterley C, et al. Store type and demographic influence on the
availability and price of healthful foods, Leon County, Floriday, 2008. Prev. Chronic
Dis.. 2011; 8, A140.
Lucan SC, Karpyn A, Sherman S. Storing empty calories and chronic disease risk:
Snack-food products, nutritive content and manufacturers in Philadelphia corner
stores. J Urban Health. 2010; 287: 394-409.
Bodor JN, Rice JC, Farley TA, Swalm CM, Rose D. The association between
obesity and urban food environments. J Urban Health. 2010; 87(5):771-81.
Special Thanks To
Aditi Puri
Jennifer
McLean
Veronica
Uzoebo
Sally
Cooper
Sheilah
Crowley
Raul
Barrios
Touro
Interns
Sarah
MacLeod
CUNY Corp
Interns