Methods The project is an unmasked randomized controlled trial with cluster design in which 60 rural village communities, each with 30 infants, within the County of Xi-Chou, Wen-Shan, Yunnan Province, SW China will be randomly selected and randomly assigned to intervention or control clusters. The intervention will be meat fed daily from age 6-18 months. Control participants will receive an equi-caloric rice-based supplement or a commercially available fortified rice cereal. The intervention team will include 80 community doctors, supervised and supported by senior staff at Xi-Chou Women's and Children's Hospital. This senior staff will be also be responsible for purchasing and quality of intervention foods. The intervention meat will be certified safe pork, because pigs are ubiquitous in rural China and can be maintained cheaply by foraging/scavenging. Lean pork, which will be increased as accepted up to a plateau of 2 oz/d, will be provided as a meat-rice recipe daily in the community doctors' homes; any food remaining will be fed at home later in the day. Control children will receive a daily plant-based recipe or fortified rice cereal also in their community doctors' homes. Starting at the time of recruitment at age 3 months, monthly nutrition education messages will be given to mothers. Initially focusing on exclusive breast feeding; after 6 months of age, education for both test and control clusters will focus on optimizing diversity of locally available, affordable complementary foods and on responsive feeding (messages designed to increase energy intake are not required in this population). Specially trained local and Shanghai health research teams will obtain longitudinal outcome measures between 6-18 months. Outcomes include: anthropometry at 6, 9, 12, 15 and 18 months; daily records of infectious disease morbidity (kept by community doctors); Bayley Scales of Infant Development III at 6, 12, 18 months plus the WHO motor questionnaire; 24-hr dietary recall data at 6, 7, 9, 12, 15 18 months; biomarkers and, on a subsample, measurements of zinc absorption and gut function at 6, 9 and 18 months. Data will be transferred daily to the local research base at Xi-Chou Women and Children's Hospital, checked for accuracy and entered into the data management system. These data will be transferred weekly to the data manager in Shanghai Jiao Tong University, School of Medicine, Xin-Hua Hospital. Data will be collated and shared with the Colorado research group at 3-monthly intervals. SAS software will be used for a range of outcome-specific statistical measures.