Background: Obesity, diabetes and cardiovascular disease are among the leading causes of death in the United States. Consumption of sugar-sweetened beverages (SSBs) such as sodas, fruit drinks and sports drinks increases risk of these preventable conditions. SSBs are particularly problematic because they are high in calories but offer little nutritional value, and because the liquid calories in SSBs cause faster spikes in blood sugar and lower feelings of fullness than solid foods.~Despite these risks, the average American adult consumes more than 130 calories per day from SSBs, well above recommended levels. A promising strategy for reducing SSB consumption is requiring health warnings on SSB containers. Online studies show that health warnings attract consumers' attention and reduce intentions to purchase SSBs. However, no research has tested the impact of SSB health warnings on actual behaviors. This randomized trial evaluates whether health warnings reduce purchases of SSBs.~Setting: The trial will take place a mock convenience store setting created for researchers to examine how store and product characteristics influence consumer purchases in a controlled but realistic environment. The store reflects a convenience store's characteristics, selling foods, beverages, and household items at real-world prices. Participants can buy these products using cash.~Recruitment: Participants will be recruited via university community subject pools, printed flyers posted, and online listings. Interested potential participants will complete an online pre-enrollment screening questionnaire to determine their eligibility. If eligible, they will be invited to schedule a time to visit the mock store for the trial.~Informed consent: At the beginning of the study visit, research staff will review the consent documents with the participants. After reviewing the form, the research staff member will ask the participant if he or she has any questions. Then both parties will sign the consent form and the participant will receive a copy of the consent form to keep.~Randomization: Participants will be randomly assigned to trial arms. An independent biostatistician will conduct the randomization a priori. Participants will have an equal chance of being randomized to either arm of the trial. Randomization will be carried out by generating a random number for each participant identification code (ID). Participant IDs will be ordered on this random number from smallest to largest. The bottom half of the IDs will be assigned to the control arm and the top half to the treatment arm (trial arms are described below). When participants arrive for their study visit, they will be assigned the next consecutive participant ID and will be allocated to the trial arm previously assigned to that ID.~Experimental Procedures: When participants arrive at the mock store, they will be provided with a shopping basket and their participation incentive in cash. Participants will be instructed to pretend they are on a usual shopping trip and reminded that there are no right or wrong products to select. They will not be told the trial's purpose.~Participants will be asked to complete a shopping task. They will be given a list of product categories and asked to select their preferred products in each of these categories. They will indicate their selections by placing products in their shopping basket. Before they begin the shopping task, participants will be instructed that they will be required to purchase one of the items they select, and that this item will be chosen for them at random by the experimenter. This procedure incentivizes participants to only select products they are actually interested in purchasing. After participants have completed the shopping task, the experimenter will randomly choose one of the products in the participant's basket for participant to purchase with his or her incentive cash. The participant will pay for the product and will receive change as necessary. After paying for their item, participants will complete a computer-based survey in another room.~Assessment: The products participants select will be recorded by the experimenter at the end of the shopping task. Participants will also complete 1 computer-based survey immediately after completing the shopping task.~Detailed description of the trial arms: Participants will be assigned to either a health warnings arm or a control arm. In the health warnings arm, all SSB products will be labeled with a health warning label. Investigators developed the text and design of these labels based on previous research and on label designs described in US and international legislation. In the control arm, all SSB products will be labeled with a neutral label, also developed by the investigators. In both arms, labels will be adhered directly on the front-of-package of SSB containers.
Consumption of sugar-sweetened beverages (SSBs) like sodas, sports drinks, and fruit drinks remains a pressing public health concern in the United States. Consumption of SSBs remains well above recommended levels, and has been linked to obesity, diabetes, and cardiovascular disease. In response, policymakers across the U.S. have proposed requiring warning messages on SSB containers to inform the public and reduce consumption to healthier levels. While online studies find that such warnings reduce intentions to purchase SSBs, no studies have yet examined the impact of warnings on actual consumer behavior. The purpose of this randomized trial is to determine whether health warnings on sugar-sweetened beverages are more effective than control labels at reducing purchases of sugar-sweetened beverages. The trial will take place in a mock convenience store. Participants will be randomly assigned to a health warnings arm in which all sugar-sweetened beverages in the store are labeled with a health warning, or to a control arm in which all sugar-sweetened beverages in the store are labeled with a neutral label. Participants will select items to purchase with cash, and purchases will be compared across trial arms.