BackgroundMasters athletes (MAs) have led a physically active lifestyle for an extended period of time or initiated exercise/sport in later life. Given the benefits of physical activity and exercise we investigated if body mass index (BMI), an indirect health indicator of obesity, was clinically superior in MAs as compared to controls or the general population.MethodsSeven databases (Medline, PubMed, Scopus, Web of Science, CINAHL, PsycINFO, Cochrane) were electronically searched for studies on BMI (kg/m2) or as a percentage of BMI categories (underweight, normal, overweight, obesity) in MAs.ResultsOf the initial yield of 7,431 papers, 60 studies met our inclusion criteria and were used in this literature review. Studies identified were classified as: endurance sports (n = 14), runners (n = 14), mixed sports (n = 8), cyclists (n = 4), soccer (n = 4) swimmers (n = 3), non-specific (n = 3), orienteering (n = 2), World Masters Games (n = 2) and individual sports (n = 5). Where BMI was presented for the group of MAs the mean was 23.8 kg/m2 (± 1.1) with a range from 20.8 kg/m2 (endurance runners) to 27.3 kg/m2 (soccer players), this was significantly lower (p < 0.001) than controls ( −9.5%, 26.13 ± 1.7 kg/m2). Where gender specific BMI was reported the mean for male MAs was 23.6 kg/m2 (± 1.5) (range 22.4 kg/m2 endurance to 26.4 kg/m2 swimmers) and 22.4 kg/m2 (± 1.2) for female MAs (range 20.8 kg/m2 mixed to 24.7 kg/m2 WMG).ConclusionIn most, but not all studies the BMI of MAs was significantly lower than controls. A clinically superior BMI affords MAs reduced risk with regard to a number of cardiometabolic diseases, osteoarthritis and certain types of cancers.