Nudging plant-based alternatives to meat and dairy in a real-life online supermarket: A randomized controlled trial.

A shift from predominantly animal-based to plant-based consumption can benefit both planetary and public health. Nudging may help to promote such a shift. This study investigated nudge effects on plant-based alternatives to meat and dairy in an online supermarket. We conducted a two-arm, parallel-group, randomized controlled real-life online supermarket trial. Each customer transaction was randomized to a control arm (regular online supermarket) or an intervention arm (addition of placement, hedonic property and dynamic social norm nudges promoting meat and dairy alternatives). Outcomes were the aggregate of meat and dairy alternative purchases (primary outcome), the number of meat purchases, dairy purchases, meat alternative purchases, and dairy alternative purchases (secondary), and retailer revenue (tertiary). Generalized linear mixed models with a Conway-Maxwell Poisson distribution were used to estimate incidence rate ratios (IRRs). Analyzed data included 8488 transactions by participants (n = 4,266 control arm, n = 4,222 intervention arm), out of which 2,411 (66%) were aged above 45 years, 5,660 (67%) were females, and 1,970 (23%) lived in socially disadvantaged neighborhoods. Intervention arm participants purchased 10% (IRR 1.10 (95% CI 0.99-1.23)) more meat and dairy alternatives and 16% (1.16 (0.99-1.36)) more meat alternatives than control arm participants, although these findings are not statistically significant. There was no difference in dairy alternative purchases (1.00 (0.90-1.10)). Intervention arm participants purchased 3% less meats (0.97 (0.93-1.02)) and 2% less dairy products (0.98 (0.95-1.02)) than control participants. Retailer revenue was not affected (0.98 (0.95-1.01)). Online nudging strategies alone did not lead to a statistically significant higher amount of plant-based purchases, but replication of this work is needed with increased study power. Future studies should also consider nudging strategies as part of a broader set of policies to promote plant-based purchases. TRIAL REGISTRATION: Prospectively registered on 14th of May 2022. ISRCTN16569242 (https://doi.org/10.1186/ISRCTN16569242).

[Financial incentives for lifestyle behavior change]. / Financiële prikkels om de leefstijl te bevorderen.

A considerable part of the burden of disease in the Netherlands is caused by unhealthy behavior. Prevention is therefore an important part of recent national agreements, which must now be given practical shape. It is widely known that behavior change is difficult and requires intervening at many levels simultaneously. A relatively scarcely used instrument are financial incentives for lifestyle behavior, despite increasing knowledge about its effectiveness. In this paper, we present ten insights from science for practice about offering financial incentives for lifestyle support, with the aim to fuel the discussion.

Cohort profile: The Corona Behavioral Unit cohort, a longitudinal mixed-methods study on COVID-19-related behavior, well-being and policy support in the Netherlands.

This 'cohort profile' aims to provide a description of the study design, methodology, and baseline characteristics of the participants in the Corona Behavioral Unit cohort. This cohort was established in response to the COVID-19 pandemic by the Dutch National Institute for Public Health and the Environment (RIVM) and the regional public health services. The aim was to investigate adherence of and support for COVID-19 prevention measures, psychosocial determinants of COVID-19 behaviors, well-being, COVID-19 vaccination, and media use. The cohort also examined specific motivations and beliefs, such as for vaccination, which were collected through either closed-ended items or open text responses. In April 2020, 89,943 participants aged 16 years and older were recruited from existing nation-wide panels. Between May 2020 and September 2022, 99,676 additional participants were recruited through online social media platforms and mailing lists of higher education organizations. Participants who consented were initially invited every three weeks (5 rounds), then every six weeks (13 rounds), and since the summer of 2022 every 12 weeks (3 rounds). To date, 66% of participants were female, 30% were 39 years and younger, and 54% completed two or more questionnaires, with an average of 9.2 (SD = 5.7) questionnaires. The Corona Behavioral Unit COVID-19 cohort has published detailed insights into longitudinal patterns of COVID-19 related behaviors, support of COVID-19 preventive measures, as well as peoples' mental wellbeing in relation to the stringency of these measures. The results have informed COVID-19 policy making and pandemic communication in the Netherlands throughout the COVID-19 pandemic. The cohort data will continuously be used to examine COVID-19 related outcomes for scientific analyses, as well as to inform future pandemic preparedness plans.

Lottery incentives for smoking cessation at the workplace: design and protocol of the smoke-free lottery - a cluster randomized trial.

BACKGROUND: Smoking is the leading behavioral risk factor for the loss of healthy life years. Many smokers want to quit, but have trouble doing so. Financial incentives in workplace settings have shown promising results in supporting smokers and their design influences their impact. Lotteries that leverage behavioral economic insights might improve the effectiveness of workplace cessation support. METHODS AND DESIGN: We examine in a cluster randomized trial if a workplace cessation group training paired with lottery deadlines will increase continuous abstinence rates over and above the cessation training alone. Organizations are randomized to either the control arm or lottery arm. The lotteries capitalize regret aversion by always informing winners at the deadline, but withholding prizes if they smoked. In the lottery-arm, winners are drawn out of all participants within a training group, regardless of their smoking status. In weeks 1-13 there are weekly lotteries. Winners are informed about their prize (€50), but can only claim it if they did not smoke that week, validated biochemically. After 26 weeks, there is a long-term lottery where the winners are informed about their prize (vacation voucher worth €400), but can only claim it if they were abstinent between weeks 13 and 26. The primary outcome is continuous abstinence 52 weeks after the quit date. DISCUSSION: There is a quest for incentives to support smoking cessation that are considered fair, affordable and effective across different socioeconomic groups. Previous use of behavioral economics in the design of lotteries have shown promising results in changing health behavior. This cluster randomized trial aims to demonstrate if these lotteries are also effective for supporting smoking cessation. Therefore the study design and protocol are described in detail in this paper. Findings might contribute to the application and development of effective cessation support at the workplace. TRIAL REGISTRATION: Netherlands Trial Register Identifier: NL8463 . Date of registration: 17-03-2020.

Commitment Lotteries Promote Physical Activity Among Overweight Adults-A Cluster Randomized Trial.

Background: The World Health Organization has identified physical inactivity as the fourth leading risk factor for global mortality. People often intend to engage in physical activity on a regular basis, but have trouble doing so. To realize their health goals, people can voluntarily accept deadlines with consequences that restrict undesired future behaviors (i.e., commitment devices). Purpose: We examined if lottery-based deadlines that leverage regret aversion would help overweight individuals in attaining their goal of attending their gym twice per week. At each deadline a lottery winner was drawn from all participants. The winners were only eligible for their prize if they attained their gym-attendance goals. Importantly, nonattending lottery winners were informed about their forgone prize. The promise of this counterfactual feedback was designed to evoke anticipated regret and emphasize the deadlines. Methods: Six corporate gyms with a total of 163 overweight participants were randomized to one of three arms. We compared (i) weekly short-term lotteries for 13 weeks; (ii) the same short-term lotteries in combination with an additional long-term lottery after 26 weeks; and (iii) a control arm without lotteries. Results: After 13 weeks, participants in the lottery arms attained their attendance goals more often than participants in the control arm. After 26 weeks, we observe a decline in goal attainment in the short-term lottery arm and the highest goal attainment in the long-term lottery arm. Conclusions: With novel applications, the current research adds to a growing body of research that demonstrates the effectiveness of commitment devices in closing the gap between health goals and behavior. Clinical Trial information: This trial is registered in the Dutch Trial Register. Identifier: NTR5559.

Emotional responses to behavioral economic incentives for health behavior change.

Many people aim to change their lifestyle, but have trouble acting on their intentions. Behavioral economic incentives and related emotions can support commitment to personal health goals, but the related emotions remain unexplored. In a regret lottery, winners who do not attain their health goals do not get their prize but receive feedback on what their forgone earnings would have been. This counterfactual feedback should provoke anticipated regret and increase commitment to health goals. We explored which emotions were actually expected upon missing out on a prize due to unsuccessful weight loss and which incentive-characteristics influence their likelihood and intensity. Participants reported their expected emotional response after missing out on a prize in one of 12 randomly presented incentive-scenarios, which varied in incentive type, incentive size and deadline distance. Participants primarily reported feeling disappointment, followed by regret. Regret was expected most when losing a lottery prize (vs. a fixed incentive) and intensified with prize size. Multiple features of the participant and the lottery incentive increase the occurrence and intensity of regret. As such, our findings can be helpful in designing behavioral economic incentives that leverage emotions to support health behavior change.

Physical activity after commitment lotteries: examining long-term results in a cluster randomized trial.

To overcome self-control difficulties, people can commit to their health goals by voluntarily accepting deadlines with consequences. In a commitment lottery, the winners are drawn from all participants, but can only claim their prize if they also attained their gym-attendance goals. In a 52-week, three-arm trial across six company gyms, we tested if commitment lotteries with behavioral economic underpinnings would promote physical activity among overweight adults. In previous work, we presented an effective 26-week intervention. In the present paper we analyzed maintenance of goal attainment at 52-week follow-up and the development of weight over time. We compared weight and goal attainment (gym attendance ≥ 2 per week) between three arms that-in the intervention period- consisted of (I) weekly short-term lotteries for 13 weeks; (II) the same short-term lotteries in combination with an additional long-term lottery after 26 weeks; and (III) a control arm without lottery-deadlines. After a successful 26-week intervention, goal attainment declined between weeks 27 and 52 in the long-term lottery arm, but remained higher than in the control group. Goal attainment did not differ between the short-term lottery arm and control arm. Weight declined slightly in all arms in the first 13 weeks of the trial and remained stable from there on. Commitment lotteries can support regular gym attendance up to 52 weeks, but more research is needed to achieve higher levels of maintenance and weight loss.

Design and protocol of the weight loss lottery- a cluster randomized trial.

People often intend to exercise but find it difficult to attend their gyms on a regular basis. At times, people seek and accept deadlines with consequences to realize their own goals (i.e. commitment devices). The aim of our cluster randomized controlled trial is to test whether a lottery-based commitment device can promote regular gym attendance. The winners of the lottery always get feedback on the outcome but can only claim their prize if they attended their gyms on a regular basis. In this paper we present the design and baseline characteristics of a three-arm trial which is performed with 163 overweight participants in six in-company fitness centers in the Netherlands.