Background and RationaleRecent reports have noted unhealthy shifts in diet and increased consumption of alcohol and sugary beverages during the COVID-19 pandemic. This dissertation delves into changes in consumption, knowledge and ways to mitigate intake of sugar sweetened beverage (SSB) intake on a university campus.
Objective
The 3 studies of this dissertation build upon each other to: (1) understand university students’ knowledge and consumption behavior of SSBs and how it changed over COVID-19; (2) determine preferences and tradeoffs people make when deciding on a beverage; and (3) Using behavioral economics to propose different policies and their likely effectiveness. The policies dissertation examines are: (1) Increasing the tax/price of soda; (2) Increasing the distance or time it takes to get soda; (3) How the funds of a SSB tax should be used.
Study Design, Settings, Participants
315 students prior and 179 during the COVID pandemic completed a 2-part survey that: (1) detailed their SSB knowledge, consumption amount and size of beverages consumed, purchasing frequency and knowledge of sugar consumption per beverage; and (2) students completed a Discrete Choice Experiment (DCE) which included five drink attributes—each with separate related choices. Participants could select from among 2 drinks which were randomly rotated. Separate analyses were run for low and high consumers to determine differences between the groups for all studies. Consumption analysis: a linear model was run to determine differences in SSB intake behavior between years. To determine knowledge of the sugar content in common SSB students were given a table of 25 beverages with pictures and names. They were asked to pick which drink they believed had added sugar. The percentage of drinks chosen was determined by how often each drink was identified as being sweetened. Additionally, they were asked to identify the correct amount of sugar in a regular soda, diet soda, water, and juice. The DCE was analyzed using a conditional logistic regression model. Willingness to pay and marginal analyses were determined for both low and high consumers.
Results
Consumption: most participants reported drinking 1 - 4 sodas per week (58%, 2018 and 57%, 2022). This is considered to be low SSB consumption among nutrition experts (Powell & Han, 2013; Rosinger et al., 2017). In 2022, students reported drinking smaller size drinks than previously conveyed, however when averaged both years reported drinking 12 oz servings. The number of participants reporting to not drink soda went down in 2022 from 17% to 14%. There was a 3% increase in soda consumption during lockdown. The percentage of students drinking 8 or more sodas also increased by 3% in 2022.
Knowledge: most students overestimated the amount of sugar in drinks. The added sugar content of milk and milk substitutes was not understood by students. Twenty-three percent of low SSB consumers believed regular milk contains added sugar. High SSB consumers were more likely to know there is not added sugar in regular milk with 100% getting this correct in 2022. The naturally occurring sugars in both milk and milk substitutes are often confused for added sugar.
DCE: Students overwhelmingly choose to drink juice or water compared to soda (p=0.00). They are willing to pay $1.75 more for water than soda when the years of the study are combined ($1.63 in 2018 and $2.02 in 2022). In addition, they would pay 75₵ more for juice than soda (71₵ and 84₵ respectively; p<0.00). When given the option of where the funds of the tax should go, participants are willing to pay 82₵ more (69₵ and $1.15, respectively; p<0.00) for the funds from the sales tax to go towards healthy foods and beverages on campus than to the general fund of the university. Students choose a lower sugar content of 6 tsp / 96 calories is significant (p=0.05) when they are making drink choices, compared to 0 sugar and calories. The time it takes to get a beverage was significant at all times compared to 0 (p<0.00). Time is an important factor when students are making drink choices. They are willing to pay 7₵ more to be able to get the drink within 0 – 5 minutes (p<0.00). When compared to no tax – tax at any level is unpopular.
In a realistic base case scenario of with the choices of water, juice, soda, and diet soda, sugar is linearized, time and tax are held at 0 and there are no funds going to any cause, 35% of students will choose water; 38% juice; 10% diet soda; and 17% soda. This differs for high SSB consumers 27% choose water, 37% juice, 11% diet soda and 24% soda. In both populations juice s the preferred choice across all scenarios. Soda consumption drops the most in the high SSB consumer group only when a $1.00 tax is applied and the revenue of the tax goes to the general fund. If the tax goes to a popular program such as decreased healthy food on campus soda is chosen 24% of the time, equal to the no tax base case for this group. This group is not affected by the time it takes to get the beverage. When a 10-minute wait is added and there is no tax the choice of soda only drops by 1% and 2% if the wait is also added to a $1.00 tax that goes to the general fund.
Conclusion
This study investigates the complex issue of SSB consumption among college students. Curbing consumption of these beverages is not as simple as adding a tax or banning these beverages on campus. Having funds go toward popular cause will raise consumption of soda. This implies that the revenue from a tax should go toward a neutral program in order to be effective. However, this will make a tax unpopular and unviable. There are simple ways to increase knowledge of healthier options. Increasing knowledge and access to healthier options is a more sustainable option for both students and the university. Behavioral economic interventions such as redesigning the cafeteria and student stores using choice architecture and implementing the stoplight labeling system for students to easily recognize healthier food and beverage options have shown to be effective and popular with students and staff.
