While all three lifestyle patterns, diet quality, energy distribution, and sleep behavior can influence diabetes management, limited research has evaluated how each individually and in combination affect glycemic control among adolescent and young adults with T1DM compared to older adults with T1DM. To address this gap, we propose to examine diet quality, meal timing specifically to energy distribution, and sleep behavior of adolescents and young adults with T1DM (n=15) compared to older adults with T1DM (n=33) who participated in the T1 DEXI pilot study.