Prior to the advent of digital photography, researchers used manual photographic methods to provide valid and reliable estimates of body volume as a means to overcome the substantial expense and participant burden associated with UWW. This evidence suggests that visual estimation of body composition can be valid, but may be limited by familiarity of the observer with the study population, subjectivity of the observer, and reproducibility of the study results.

Previous studies employing visual estimation have found that both trained and untrained observers can provide moderately accurate estimates of percentage BF by visually inspecting an individual directly or from photography with correlations between observations and criterion measures, such as under water weighing (UWW) ranging between r = 0.56 and 0.83. Our approach to using digital images to assess human body composition is predicated on evidence from studies done as early as the 1930’s using either visual estimation or photographic assessment of body volume, from which body composition could be determined. This method has the potential to overcome limitations associated with BMI particularly the misclassification of obesity among individuals who have relatively high lean mass (i.e. The use of digital photography may be a viable alternative to BMI for the assessment of human body composition in field research. Therefore, there is significant need for a simple, portable, and relatively inexpensive but accurate measurement of body composition that performs well across age, sex, and racial/ethnic groups. Similarly in adults, BMI misclassified obesity status differentially by race/ethnicity and age. In children, age- and sex-specific BMI percentiles have been found to underestimate the prevalence of excess adiposity when compared to DXA particularly among whites and Mexican American youth. It is well-documented that obesity is often misclassified when BMI is used as a proxy for body fatness compared to measurement techniques via imaging. Therefore, body mass index (BMI kg/m 2) is a commonly used alternative, but is limited in that it is an assessment of body weight relative to height and not of body composition per se. Furthermore, field methods such as multiple skinfold measurements depend heavily upon repeated training of research staff to obtain accurate and reliable assessments. Both obesity and sarcopenia can be assessed using highly accurate techniques such as dual-energy x-ray absorptiometry (DXA) or magnetic resonance imaging (MRI) but are not widely used in large-scale epidemiologic studies or non-clinical settings due, in part, cost and size of the equipment used for these methods. Obesity, characterized by an excess of body fat (BF) and sarcopenia, defined as diminution of primarily skeletal muscle, remain significant public health problems.

Nevertheless, challenges remain in the determination of these aspects of body composition in research. Assessment of body composition, particularly fat and fat-free mass, is vital to understanding many health-related conditions including cachexia induced by HIV, cancer, and other diseases multiple sclerosis wasting in neurological disorders such as Parkinson’s, Alzheimer’s, and muscular dystrophy sarcopenia obesity eating disorders proper growth in children, and response to exercise.

Different body fat percentages pictures