Widen is an interdisciplinary nutritional epidemiologist and takes a life course approach to nutritional sciences at the intersection of nutrition, perinatal, and pediatric epidemiology, and human biology. She develops and applies advanced analytic methods and interdisciplinary approaches to rigorously evaluate the role of nutrition during the 1,000 days on short and long-term health of mothers and their children. In her research, Widen has significantly contributed towards the understanding of determinants and outcomes of body weight and body composition changes during pregnancy and postpartum in different populations. She leads the Mother Infant Nutrition Study (MINT), a longitudinal prospective pregnancy cohort study in the Austin area designed to evaluate how maternal weight and body composition trajectories during pregnancy (assessed with magnetic resonance imaging) are related to neonatal and infant adiposity, and other health outcomes. She is Co-PI of the Mothers and CAreGivers Investing in Children (MAGIC) study, a mother-caregiver infant feeding intervention program among low-income Hispanic families that focuses on healthy eating during infancy and responsive caregiving in relation to nutrition and body composition outcomes. In addition, she leads several other projects focused on maternal and child nutrition among high risk populations, including examining pregnancy outcomes among women with twin gestations and women with obesity, and investigating maternal and offspring body composition among HIV-exposed and unexposed dyads in Kenya and Uganda.