Table 3. Mean Discount Savings and Percentage Change in Spending Associated With Increases in Discount Savings Among Supermarket Shoppers, Philadelphia, Pennsylvania, April through August 2010 and December 2010 through October 2012.

Food Category	Mean Discount Savingsa, % (95% CI)c	Mean Change in Spending, Unadjusteda		Mean Change in Spending, Adjusteda , b
		% (95% CI)d	P Valuee	% (95% CI)d	P Valuee
Low-calorie foods	21.2 (18.6–24.2)	17.8 (10.2–21.7)	<.001	2.9 (0–4.6)	.08
Fruit	4.3 (3.6–5.2)	12.7 (2.5–17.6)	.002	6.7 (0.9–11.3)	.03
Vegetables	22.6 (19.3–26.3)	12.7 (8.3–23.4)	<.001	−1.2 (−6.0 to 3.7)	.55
Low-fat dairy	43.8 (42.8–44.4)	5.8 (−8.9 to 15.0)	.60	−10.5 (−43.8 to 9.1)	.44
High-calorie foods	23.5 (21.5–25.6)	9.5 (8.8–12.6)	<.001	3.3 (1.6–5.9)	.002
Sweet snacks	3.9 (3.3–4.5)	9.9 (6.9–11.4)	<.001	5.2 (2.2–7.2)	<.001
Savory snacks	24.8 (22.8–26.8)	23.3 (11.7–28.2)	<.001	1.6 (−7.9 to 3.0)	.61
Sugar-sweetened beverages	37.9 (34.9–40.7)	11.4 (10.4–18.8)	<.001	5.3 (4.5–12.3)	.001
Grain-based snacks	20.9 (18.9–23.1)	9.1 (5.7–10.2)	<.001	−0.01 (−3.5 to 1.6)	.97

Abbreviation: CI, confidence interval.

^a Spending is defined as the purchase price minus any discount savings and thus equal to the amount paid by the shopper, expressed as a percentage of dollars spent on all foods in the category.

^b Adjusted analyses control statistically for the number of ounces purchased.

^c Savings is defined as the dollar amount by which the purchase price was reduced by discounts, expressed as a percentage of dollars spent on all foods in the category.

^d All 95% CIs are bias corrected and accelerated with estimates based on 1,000 bootstrap samples.

^e P values were obtained from fixed effects generalized linear models with gaussian distribution and log links.