Chrononutrition is the study of interactions between diet, circadian rhythms, and sleep, and their impact on health. Misalignment between circadian rhythms and the timing of eating may have adverse effects on metabolic function and increase risk of weight gain. Poor sleep behaviours and sleep function - including short sleep, irregular sleep, and poor sleep quality - are associated with increased risk of cardiometabolic disease, overweight and obesity, and poor diet quality. Our research involves observational and interventional studies to investigate whether combining sleep behavioural change with lifestyle interventions can support better adherence and ultimately improve health outcomes.