RecruitingBehavioural interventionHealthy Lifestyles in Bipolar Disorder: Bay Area StudyThe goal of this clinical trial is to understand how level of adherence with time-restricted eating (TRE) predicts change in diurnal rhythms (as measured using the amplitude of diurnal peripheral clock gene expression), and how those changes predict lower mania and depressive symptoms, and downstream improvements in quality of life. The effects of diurnal amplitude of clock gene expression is expected to remain significant when controlling for change in glucose tolerance and inflammation. Participants will be enrolled who are already receiving medication treatment for bipolar disorder. Participants will complete daily measures of eating, sleep and mood for two weeks, and then will be assigned to follow TRE for eight weeks. Symptoms and Quality of Life will be measured at baseline and during and after the food plan.