Based on our prior pilot data, the mean yearly change in TBBMC in 30 HIV-infected children between the ages of 7-14 years was 120 g with a standard deviation of 84. A difference in SD between boys and girls was noted. In order to maintain conservative estimates we chose SD observed in girls. This can be assumed to be the level of yearly change that will be observed in the placebo group. Based on data from the Pediatric Rosetta Project (NIDDK 37352), a cross-sectional study of >1300 children, the mean yearly change in TBBMC in healthy African-American and Hispanic children ages 7-14 years is 195 g.