Study finds two thirds of women of normal BMI have ‘normal weight obesity’
New research presented at this year’s International Congress on Obesity shows that among a sample of Brazil women with normal weight, two thirds (67%) are experiencing a phenomenon called ‘normal weight obesity’, whereby despite being in the normal range for body mass index (BMI), that have a very high body fat percentage of 30% or over. The study is by Dr Larissa Luna Queiroz, Universidade Federal do Ceará Fortaleza, Ceará, Brazil, and colleagues.
Normal weight obesity (NWO) in adults is a condition characterised by a high percentage of body fat (in most previous studies, this means > 30% in women) and a body mass index (BMI) within the normal range (18.5-24.9 kg/m2). Analysing the distribution of this central fat becomes particularly relevant for females, as the accumulation of fat mass is often overlooked in this population, as it is less associated with comorbidities, especially in young women.
In this study, the authors assessed the prevalence of NWO and the distribution of fat in a population of healthy women with normal weight. This is a cross-sectional study conducted at Walter Cantídio University Hospital, Fortaleza, Ceará, involving healthy adult women in the normal BMI range (18.5-24.9 kg/m2), sequentially selected from students and staff of the institution. All volunteers underwent assessment of body composition using dual-energy X-ray absorptiometry and anthropometric measurements by the same qualified examiner.
A total of 220 volunteers were evaluated, with a mean age of 29 years and mean BMI of 22 kg/m2. The mean waist-to-hip ratio (WHR) was 1.0, indicating a high level of abdominal (central) obesity, and the mean body fat percentage (%BF) in the population was 33.8%. The prevalence of NWO (body fat above 30%) was 67.3% in this population, and of these, 31.4% had an abnormally high WHR higher than 1.0 (the higher the WHR, the higher the risk of cardiovascular disease and other health problems) Overall, the women with NWO had a high % body fat (43%) in the gynoid region, which includes the hips and upper thighs, and overlaps both the leg and trunk regions. Dr Queiroz explains: “Body fat distribution is a significant indicator of cardiovascular risk. Knowing your location is as important, or perhaps even more relevant, than knowing your total amount of body fat.”
The authors say: “A high prevalence of normal weight obesity was observed in this population, and despite the predominance of young women, around one third of those with normal weight obesity displayed a higher metabolic risk as shown by abnormally high waist-to-hip ratio. These findings highlight the need for attention to obesity and its complications even in young women with a normal BMI.”
The implications of the research are that millions of additional Brazilian women could be ‘technically’ obese, despite outwardly appearing a normal weight and size. Dr Queiroz explains while her team’s study involved mostly younger women, this phenomenon of normal weight obesity could be even more pronounced in older Brazilian women of normal BMI, as older people tend to have a higher % of bodyfat.
She concludes: “If younger Brazilian women want to know if they are at risk of having normal weight obesity, we tend to observe a very high body fat percentage in individuals of normal weight/BMI who lead a sedentary lifestyle and frequently eat out. Therefore, if a young woman finds herself in this situation and, despite having a normal weight does not visibly see her muscles when contracted, we would recommend that she requests a body composition assessment from her healthcare professional. Anyone found to be at increased metabolic risk can then be given diet and lifestyle advice to help lower their body fat.”
Dr Larissa Luna Queiroz, Universidade Federal do Ceará Fortaleza, Ceará, Brazil. Please contact by e-mail. E) larissa.luna@yahoo.com.br
ICO 2024
The International Congress on Obesity (ICO 2024) is hosted by the World Obesity Federation, in partnership with member organisation the Associação Brasileira para o Estudo da Obesidade (ABESO). ICO 2024 takes place at the Frei Caneca Conventions Center in São Paulo from 26 - 29 June.
ICO 2024