Objectives A key challenge for behaviour change is by-passing the influence of habits. Habits are easily triggered by contextual cues; hence context changes have been suggested to facilitate behaviour change (i.e., habit discontinuity). We examined the impact of a COVID-19 lockdown in England on habitual consumption of sugar-sweetened beverages (SSBs). The lockdown created a naturalistic context change because it removed typical SSB consumption situations (e.g., going out). We hypothesised that SSB consumption would be reduced during lockdown compared to before and after lockdown, especially in typical SSB drinking situations. Design In two surveys among the same participants (N = 211, N = 160; consuming SSBs at least once/week) we assessed the frequency of SSBs and water consumption occasions before (Time 1), during (Time 2) and after lockdown (Time 3), across typical SSB and water drinking situations. We also assessed daily amount consumed in each period, and perceived habitualness of drinking SSBs and water. Results As predicted, participants reported fewer occasions of drinking SSBs during lockdown compared to before and after, especially in typical SSB drinking situations. However, the daily amount of SSBs consumed increased during lockdown, compared to before and after. Exploratory analyses suggest that during lockdown, participants increased their SSB consump¬¬tion at home, especially if they had stronger perceived habitualness of SSB consumption. Conclusion These findings suggest that SSB consumption is easily transferred to other situations when the consumption context changes, especially for individuals with strong consumption habits. Habitual consumption may be hard to disrupt if the behaviour is rewarding.What is the motivation for consuming sugary drinks? Why do some people choose Coke, and others water, to accompany their dinner or to quench their thirst? We know very little about the psychological processes underlying these behaviours. While the motivation for unhealthy food has been researched extensively, the motivation for sugary drinks remains understudied, despite their negative health implications. Up to 19% of daily calorie intake consists of sugar from drinks, and the consumption of sugary drinks contributes to weight gain. The consumption of sugary drinks is a main contributor to poor dental health and to overweight, which cost the NHS £ 3.4 billon and £ 4.7 billion a year in England alone (Public Health England, 2014). Especially given the recent media attention, many consumers are aware of the health implications of sugary drinks, but struggle to successfully reduce their intake. Therefore, it is important to understand what underlies the motivation for sugary drinks, and how we can effectively assist consumers in replacing sugary drinks with healthier alternatives such as water. We propose that sugary drinks gain their attractiveness through consumption and reward simulations. In other words, when people see or think about a sugary drink, they spontaneously simulate (i.e., re-experience) the sensation and the reward of consuming it, such as its taste, the resulting energy boost, and the quenching of thirst, based on their previous, rewarding experiences. These simulations trigger a desire to consume sugary drinks, particularly when feeling thirsty. Although evidence exists for the role of such simulations in the motivation for food, no previous studies have applied this account to drinks. Our research will first systematically test this simulation account of the motivation for sugary drinks, and then use it to stimulate healthier choices in innovative ways. In Subproject 1, we will investigate the specific simulations that are triggered by sugary drinks and by water. Building on recent pilot data that we have collected, we expect that sugary drinks will trigger more consumption and reward simulations ("cold", "fizzy", "tasty", "refreshing") than water, particularly among high consumers of sugary drinks, and particularly when thirsty. In Subproject 2, we will link these consumption and reward simulations to the motivation to consume sugary drinks and water. To this end, we will use a novel method to assess motivation unobtrusively: we will measure the degree to which participants slightly lean forward on a Wii balance board when viewing images of drinks. Such subtle approach movements have been shown to reflect motivation and desire. We predict that more consumption and reward simulations will be associated with leaning forward more toward sugary drinks images, especially among high consumers of sugary drinks and especially when thirsty. Finally, in Subproject 3, we will use these findings to develop an intervention approach to help consumers replace sugary drinks with water. Typically, advertisements for sugary drinks focus heavily on consumption and reward, whereas advertisements for water focus on purity and health benefits. We propose that motivation for consuming water can be increased by boosting consumption and reward simulations, in a similar way as for sugary drinks. Thus, we will test whether using images and words that trigger consumption and reward simulations for drinking water makes water more attractive and increases water choices, and reduces choices for sugary drinks. We will test this in both online and field experiments with actual consumers in naturalistic settings. Together, these experiments will help us understand what makes sugary drinks so difficult to resist, and how health practitioners, intervention developers, and industry can boost the motivational appeal of healthier alternatives to stimulate healthier beverage choices.

Participants were recruited through an announcement on Prolific (https://www.prolific.co) detailing the purpose and duration of the experiment. Informed consent was obtained from participants prior to the study. We included participants who were between 18 and 70 years old, where a resident in the UK, and had not previously participated in any of our other studies. The study consisted of a survey that participants filled in online at a location of their choice.