The investigators will compare weight gain based on fat accretion and change in body composition in preterm infants receiving different amounts of enteral protein.

American Academy of Pediatrics guidelines define the growth rate of preterm, underweight babies as adequate if it matches the age-equivalent weight gains typical of term infants, approximately 10-15 grams per kg per day. Unfortunately, many pre-terms, especially very low birth weight ones, do not achieve this rate, resulting in neurodevelopmental deficits and low discharge weights. Typical feeding regimens, designed to increase weight gain, however, have been shown to increase the rate of fat accretion and increase the risk of obesity and metabolic disorders, such as insulin resistance and type 2 diabetes, later in life. Research has shown that higher protein diets can reduce the accretion of body fat in older, normal weight infants but this has not been systematically tested in low birth weight pre-terms. The current study will compare weight gain based on fat accretion and change in body composition in preterm infants receiving higher (4g/100 kcal) versus lower (3 g/100 kcal) protein-energy ratio diets. The hypothesis tested in this study is: Increased protein intake will reduce the percentage of weight gain due to fat accretion in pre-term infants. The identification of an effective feeding regimen that would both allow pre-term infants to acquire age-equivalent growth rates similar to those of term infants while avoiding the excess accretion of body fat could significantly improve the long term health outcomes of this high-risk population.

Inclusion Criteria:

• Premature infants born less than 32 weeks EGA
• Growth that is appropriate for gestational age (AGA)
• Admitted to OU Children's NICU, inborn or outborn
• Receiving enteral feedings <100 mL/kg/day
• Hemodynamically stable

Exclusion Criteria:

• Severe congenital anomalies to include congenital heart disease, chromosomal anomalies, open neural tube defects, and/or intestinal anomalies precluding enteral feedings
• Growth restriction, growth that is small for gestational age (SGA) or large for gestational age (LGA)
• Inborn errors of metabolism
• History of necrotizing enterocolitis Bell stage III
• Cerebrospinal fluid indwelling shunt (affects body composition measurements)
• Expected death prior to 36 weeks EGA (the end of the study period)
• Inability to meet Pea Pod® requirements for the first measurement
• On vasopressor medications