Encouraging Healthy Food Shopping and Eating Behaviors by Price Reduction: A Community Supermarket Study

• Body weight [ Time Frame: Assessed every 4 weeks for 16 weeks (weeks 0, 4, 8, 12, 16) ] [ Designated as safety issue: No ]
  Body weight is measured in a private area of the supermarket during participant visits every 4 weeks for 16 weeks (4 weeks of baseline period, 8 weeks of intervention period, 4 weeks of follow-up period).
• Food intake [ Time Frame: Assessed every 4 weeks for 16 weeks (weeks 0, 4, 8, 12, 16) ] [ Designated as safety issue: No ]
  Food intake is assessed via 24-h dietary recalls conducted over the phone by trained research assistants. Calls are made every 4 weeks for 16 weeks (4 weeks of baseline period, 8 weeks of intervention period, 4 weeks of follow-up period).
• Food purchasing ($) [ Time Frame: 4-week blocks for 16 weeks ] [ Designated as safety issue: No ]
  Purchasing is tracked automatically via store scan cards. Results are measured as the total dollars spent in a 4-week block (a 4-week baseline period, two 4-week blocks comprising the 8-week intervention period, and a 4-week follow-up period).

The investigators plan to test the effect of price reduction of fruits and vegetables and non-caloric beverages on food purchasing, food intake, body weight, and body composition of primarily single adult shoppers. One hundred subjects will be randomized to an experimental or control group for a 4 month period. In the experimental group, there will be an automated 50% reduction in fruits vegetables and non-caloric beverages during the middle 2-month period. The investigators expect to observe significant changes in food shopping and eating behavior during this period, which should lead to body weight and fat loss. Some of these new shopping patterns should persist in the last month of the study even though prices revert.

• Experimental: Discount intervention
  Receives 50% discount intervention on selected fruits and vegetables at participating supermarket.
  Intervention: Behavioral: Discount intervention
• No Intervention: Control
  Received no discount at the participating supermarket.

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Inclusion Criteria:

• regularly buy 50% of groceries at designated supermarket
• primary food shopper for household, shopping for up to one other person, not counting children ≤ 6 years old

Exclusion Criteria:

• significant medical or psychiatric conditions
• participation in a weight loss program or a related study

• Robert Wood Johnson Foundation
• Columbia University