Milk provides various nutrients such as calcium, protein, and vitamin D, which are essential for health and brain development. In the US, it is advised that children switch from the recommended whole cow's milk from ages 1-2 to low-fat or non-fat milk after age 2 to reduce saturated fat and calorie intake, however, few studies support this recommendation. Nutrition Policy Institute researchers and Anisha Patel with the Stanford Medicine Department of Pediatrics recently received funding for a research study from the National Institute of Health. The study, Milk Type in Toddlers or Milk-TOT, includes a randomized controlled trial that will investigate how whole and low-fat 1% milk affect child adiposity, dietary intake, and health outcomes, aiming to provide evidence-based recommendations for dietary guidelines. The California Dairy Research Foundation provided additional funding to include the assessment of the impacts of varying milk types on participating children's gut microbiota diversity, in collaboration with Justin Sonnenburg with the Stanford Medicine Department of Microbiology and Immunology. Parents or caregivers with children between 23-30 months old living in the San Francisco Bay Area may be eligible to participate in the study. The four-year project began in January 2024 and is estimated to end in June 2028. The project is led by Lorrene Ritchie as the principal investigator, and NPI researchers, Kassandra Bacon, Ryan Williams, Suzanne Rauzon, Celeste Felix, Hannah Thompson, Fanta Jimissa, Reka Vasicsek and Meirong Liao.