The aim was to compare the relationship between body composition and body size in two subgroups with different metabolic risk. Body-mass index z-scores (BMIZ), bicipital, tricipital, subscapular and iliac thicknesses were determined in 178 India-originating Guadeloupian (IOG) adolescents and 481 controls of other origins. Various equations were tested in a regression approach to fit the relationship between BMIZ and iliac thickness, and BMIZ and sum of skinfold thickness. A shift towards higher iliac thickness for a given BMIZ was observed in IOG adolescents. This supports the idea that the relationship between BMI and risk for non-communicable diseases is ethnicity-dependant.