The overall objective of this project is to understand how consuming a prescribed diet of different infant foods (which may contain cereals,fruits, vegetables, meats, dairy) during the time of early complementary feeding (~5 to 12 months) in breastfed infants has on growth trajectories, neurodevelopment and sleep patterns in relation to gut microbiota, compared with a traditional diet that is usually provided in the home to infants.

The three primary aims include:

Aim 1: Identify the effects that the prescribed early complementary feeding specific study diet has on growth trajectories in breastfed infants.

Aim 2: Identify whether the relationship between the prescribed early complementary feeding specific study diet and growth is mediated by gut microbiota.

Aim 3: Characterize infant neurodevelopment and sleep patterns.

Some details are intentionally left to out to preserve the scientific integrity of the study, and they will be included in the record after the study is completed.

Inclusion Criteria:

• Full term: gestational age > 37 weeks
• Exclusively breastfed (< 2 weeks of cumulative formula exposure). Any formula consumption on a given day is considered one day of formula exposure. During the intervention, if the participant receives more than 50% of the liquid diet from infant formula, s/he will be excluded from the study.
• Maternal conditions such as gestational diabetes mellitus, preeclampsia, multiple pregnancies are acceptable.

Exclusion Criteria:

• Large for gestational age or small for gestational age
• Antibiotic use from birth to the time of enrollment
• Documented food allergies
• Previous complementary food exposure
• Conditions that would affect protein metabolism or growth