Lay summary
Sugar reduction has been the focus of dietary restraint and public health educational initiatives. Yet, around half of the population in Aotearoa New Zealand continue to overconsume sugar despite short- and longer-term harm. This study hypothesises that sugar is an addictive substance that produces symptoms like craving, withdrawal, and loss of control, and that some people are more vulnerable to sugar addiction than other people. This study will be the first to use a smartphone app to assess sugar addiction in real-time and in real-world settings. The study will prompt participants to reduce sugar consumption to within the World Health Organisation recommendations to observe the presence of withdrawal, craving, triggers, and loss of control. If hypotheses are substantiated, this will pave the way for radical new approaches to early intervention and treatment for excessive sugar consumption such as delivery of non-dietary interventions delivered by addiction specialists.