We employ the measures traditionally used to analyze poverty, for studying the differences in the Body Mass Index (BMI) scores, according to the age and other socioeconomic variables, for people between 20 and 60. We use information from Demographic and Health Survey (DHS, 2005). We find that the participation of population with a BMI out of the normal range enhances with age. Nevertheless, if the measure of reference is not the normal range but a relative measure (which takes into account the distribution of the BMI in the respective group of age), differences among groups are less. Although inequality in the distribution of BMI does not enhance with age, the increases produced should be attended to avoid problems of public health in Colombia.