The Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) was launched in 1974. Its goal was to provide supplemental foods that would supply nutrients lacking in the diets of low-income pregnant, breastfeeding, or postpartum women, infants, and children less than 5 years of age, who had at least one nutritional risk factor. The WIC program also provides nutrition education and referrals to health and social services. The U.S. Department of Agriculture’s Food and Nutrition Service requested that the Institute of Medicine undertake a review of the WIC food packages to align the program with dietary guidance in the 2015 Dietary Guidelines for Americans. In response, the IOM convened the Committee to Review WIC Food Packages to address this task. This, the phase I interim report, is the second of three reports. The first report, the Evaluation of White Potatoes in the Cash Value Voucher: Letter Report, recommended allowing white potatoes for purchase with the cash value voucher. This second report presents the evidence, analyses, and framework that will be applied to develop the final report (phase II), which will include recommendations.