Abstract
Sugar-sweetened beverages (SSBs) are widely consumed globally, with intake levels exceeding the recommended daily limits for free sugars in many countries. As the largest source of added sugars in modern diets, SSBs provide calories without essential nutrients, contributing significantly to poor dietary quality and various health problems, including obesity, type 2 diabetes, cardiovascular diseases, dental caries, and osteoporosis (Malik & Hu, 2022; Brownell et al., 2009; Malik et al., 2013; Mozaffarian et al., 2011; Li et al., 2021; Peñalvo, 2024).
In response to these public health concerns, SSB taxes have been implemented in over 45 countries to promote better nutrition, improve health outcomes, and generate revenue for public health initiatives. Meta-analyses have shown that such taxes are associated with higher prices for taxed beverages and significant reductions in sales, with consumption decreasing by up to 12% for every 10% increase in price (Cabrera Escobar et al., 2013; Andreyeva, 2022). Despite some studies demonstrating the effectiveness of SSB policies, SSB taxes face challenges, including cultural variability, regressive economic impacts, and uneven effectiveness across regions and beverage types.
In Western countries, most studies on SSB taxes have focused on carbonated drinks, with limited attention to other beverage categories (Gollust et al., 2014; Bélanger-Gravel et al., 2019; Pell et al., 2019). In Asia, taxation policies similarly target standardized beverages (ready-to-drink SSBs), such as canned or bottled drinks, as these are easier to regulate due to consistent sugar content. For example, Thailand implemented a six-tiered tax rate in 2017 for drinks containing over 6 grams of sugar per 100 milliliters, while Malaysia introduced a similar policy in 2019, taxing beverages with sugar content exceeding 5 grams per 100 milliliters. Malaysia’s 2024 budget further proposes increasing the tax, reflecting the region’s ongoing commitment to sugar reduction (Phulkerd et al., 2020; Ku et al., 2024). However, these policies do not address non-standardized beverages like handmade drinks, which are more prevalent in Taiwan and some other Asian countries or even the café shops in Western countries. Additionally, the effectiveness of such policies has shown mixed results. For instance, a study in Singapore found that modest price differences highlighted through tax and subsidy messaging had little impact on high-sugar beverage sales in vending machines (Seah et al., 2018).
Taiwan represents a unique case for SSB taxation due to its distinctive beverage culture, dominated by hand-shaken drinks like bubble tea. Between 2009 and 2020, annual revenue from beverage shops in Taiwan more than doubled, from NT$43.3 billion to NT$97.8 billion . Bubble tea, often made with tea, sweetened milk, and tapioca balls, has become a cultural phenomenon. These beverages are typically customized by consumers in terms of sugar levels and ice content, complicating the standardization of sugar content and posing challenges for taxation policies based on fixed sugar measurements (Chang et al., 2021).
Sweetened beverages in Taiwan contain an average of 9.19 grams of sugar per 100 milliliters. A single medium (500 ml) or large (700 ml) serving often exceeds the recommended daily limit for added sugar intake, which is set at 10% of total daily calories—about 50 grams for a 2,000-calorie diet . For example, a 700 ml bubble tea with “full level of sugar” customization contains over 52.5 grams of added sugar, already surpassing the daily limit in one drink (Tseng et al., 2010; Pan, 2020; Shih et al., 2020).
A national survey found that 42.2% of adults aged 19 to 44 consume at least one sugary beverage daily, with males drinking more frequently than females. Teenagers in Taiwan consume nearly twice as much sugary beverages as their peers in other countries. This overconsumption contributes to significant health risks, including obesity, diabetes, and dental problems. The resulting healthcare costs are substantial, with an estimated annual expenditure of NT$87 billion for primary diagnoses related to sugary drink consumption and NT$233 billion for combined primary and secondary diagnoses (Chang et al., 2021).
Nudging strategies have been widely used to encourage healthier food and beverage choices (Grech and Allman-Farinelli, 2015; Hendren and Logomarsino, 2017). These interventions are often categorized into two main types: priming, which involves increasing the visibility, accessibility, and availability of healthier products, and salience, which uses prompts such as front-of-pack calorie labels, traffic light labels, or descriptive labels to attract consumer attention. Recent research suggests that front-of-pack labels, including text warnings, graphic warnings, sugar content indicators, and Health Star Ratings (HSR), can reduce the selection of sugary beverages among young adults (Billich et al., 2018).
However, the effectiveness of these approaches varies. For instance, Hoenink et al. (2021) found that a traffic light sugar labeling system on store shelves did not significantly reduce unhealthy beverage sales or increase healthier beverage choices. Other studies have examined the use of traffic light labels, symbolic labels, and numeric labels to nudge healthier food choices (VanEpps et al., 2016; Haasova and Florack, 2019; Franckle et al., 2018; Ellison et al., 2014). Most findings suggest that symbolic or traffic light labels are more effective than numeric labels. For example, Mauri et al. (2021) compared traffic light labels with sugar teaspoon imagery in an online experiment and found that sugar teaspoons were more effective for prompting healthier choices, though this effect was limited to smoothies. To date, no studies have applied sugar cube imagery to handcrafted beverages, making this a novel aspect of our research.
In this study, we aim to compare the effects of three informational strategies—numeric calorie imagery, traffic light imagery, and sugar cube imagery—on reducing the added sugar content in handcrafted beverages. The sugar cube imagery will visually represent the amount of sugar added to each drink, which is designed to provide a clearer understanding of sugar content and its implications for health. Additionally, we propose a novel sugar policy—a no-sugar subsidy, as opposed to a sugar tax—to reduce sugar intake within Taiwan’s unique dietary culture.
Furthermore, there is a growing recognition of the interplay between health-conscious behaviors and pro-environmental actions. For example, individuals adhering to health-conscious dietary patterns tend to report lower greenhouse gas emissions, driven by reduced energy intake rather than specific dietary choices (Asvatourian et al., 2018). Encouraging individuals to take responsibility for their health may also foster positive attitudes toward sustainability, including recycling and energy-saving behaviors (Castellini et al., 2023; Urbanovich and Bevan, 2020). This potential alignment between health and environmental objectives provides an opportunity to design interventions that simultaneously address these dual goals.
To test these concepts, we will conduct a three-stage field experiment in a bubble tea store, aiming to understand the effects of informational and financial interventions on consumer behavior:
1. Baseline Data Collection: For one month, we will gather data on beverage sales, including details of added sugar levels, without implementing any interventions. This will establish a benchmark for consumer behavior under normal conditions.
2. Information-Based Interventions: Over three weeks, we will display different informational prompts at the ordering counter, each presented for one week. These include numeric calorie labels, traffic light labels, and sugar cube labels to indicate the added sugar content. By testing these strategies, we aim to evaluate their effectiveness in reducing sugar consumption across approximately 4,000 cups purchased.
3. No-Added Sugar Subsidy: For the final two weeks, we will introduce a NT$5 discount per cup for consumers who opt for no-added-sugar beverages. In addition to collecting sales data on approximately 2,500 cups, we will recruit 500 participants to complete surveys capturing data on dietary habits, physical and mental health, pro-environmental behaviors such as using reusable cups, and beverage purchasing patterns. These surveys will provide additional insights into how financial incentives interact with consumer characteristics to influence decision-making.
This comprehensive approach aims to address gaps in health promotion and environmental sustainability in consumer behavior research. By examining the impacts of sugar content information and a no-sugar subsidy on handcrafted beverage purchase behavior, the findings will inform policymakers on how to design effective health and sustainability strategies tailored to Taiwan’s unique beverage market.