Obesity is becoming a growing problem for Americans and other people throughout the world. Obesity increases the risk of cardiovascular disease by being associated with several conditions such as type 2 diabetes, high blood pressure, and abnormal lipid parameters. Individuals who are overweight and obese are more likely to develop insulin resistance, a precursor to the development of type 2 diabetes. In addition to the obesity epidemic, there has been a parallel epidemic in type 2 diabetes. The worldwide rate of type 2 diabetes has more than doubled over the past 30 years. We have previously discussed the reasons why belly fat is so bad for your health. New research now suggests that all types of obesity do not confer the same health risks, and that intra-abdominal obesity (belly fat) is more detrimental to health.
Researchers, led by Dr. James de Lemos from University of Texas Southwestern Medical Center, have shown that visceral or intra-abdominal fat is associated with greater risk of prediabetes and type 2 diabetes in obese adults. The results of their study were published online in the Journal of the American Medical Association. The researchers performed a prospective study involving 732 obese adults aged 30 to 65 years without diabetes or cardiovascular disease who were enrolled in the Dallas Heart Study. The study participants were followed for a median of 7 years. The study participants were evaluated for body fat composition by dual energy x-ray absorptiometry and magnetic resonance imaging. In addition, circulating adipokines and biomarkers of insulin resistance, dyslipidemia, and inflammation were assessed. It was found that higher visceral fat mass, fasting glucose level, family history of diabetes, systolic blood pressure, and weight gain over the follow up period were independently associated with type 2 diabetes. There was no association between type 2 diabetes and body mass index, total body fat, or abdominal subcutaneous fat.
The authors wrote, “Adipose tissue dysfunction is characterized by ectopic fat deposition in theabdominal viscera and liver, inflammatoryand adipokine dysregulation, andinsulin resistance and may be a moreimportant mediator of diabetes development than total fat mass in obese individuals… Among obese individuals without prevalent [cardiovascular disease], a dysfunctional adiposityphenotype, characterized by excessvisceral fat and biomarkers of insulinresistance, was independently associated with the development of prediabetesand diabetes”.
The authors also wrote, “… we show that markers of generaladiposity that are associated with diabetesin the general population, suchas [body mass index], total body fat, and abdominalsubcutaneous fat, were not associatedwith prediabetes or diabetes incidencein this obese population. Thesefindings suggest that clinically measurable markers of adipose tissue distributionand insulin resistance may be useful in prediabetes and diabetes riskdiscrimination among obese individualsand support the notion of obesityas a heterogeneous disorder with distinctadiposity subphenotypes”.
The authors concluded, “Our results confirm that visceral, but not general, adiposity wasindependently associated with incidentdiabetes in a diverse population of obese individuals with a high proportionof women and African American participants while extending thisknowledge to both incident prediabetesand diabetes”.
The findings in this study are important and clearly show that all types of obesity do not carry the same health risks. It is clear that belly fat, or visceral fat is much more detrimental to health when compared to subcutaneous fat. Belly fat increases the risk of developing insulin resistance, prediabetes, and type 2 diabetes. These conditions are associated with a long list of cardiovascular complications, such as heart attack and stroke. In addition to identifying belly fat as the key to increased risk of diabetes in obesity, the researchers also have found that other types of obesity were not associated with it. This is important because it allows us to target those individuals with increased belly fat for more aggressive weight loss interventions.
Ian J. Neeland et al. “Dysfunctional Adiposity and the Risk of Prediabetes and Type 2 Diabetes in Obese Adults” JAMA2012;308(11):1150-1159. doi:10.1001/2012.jama.11132