Visceral adipose tissue: a critical review of intervention strategies

OBJECTIVE: To review the published literature regarding the effect of caloric restriction, pharmacologic intervention, and exercise to promote the loss of visceral adipose tissue (VAT) DESIGN: A review was conducted of published studies which measured VAT using computed tomography or magnetic resonance imaging before and after caloric restriction, pharmacologic therapy, or exercise. STUDIES REVIEWED: 23 separate studies were reviewed. Men represented 38% and women 63% of the 599 volunteers. There were 17 black volunteers and 30 patients with NIDDM included in these studies. MEASUREMENTS: Data regarding the baseline and change in VAT, body fat, and body weight were collected. RESULTS: Most interventions demonstrated a preferential loss of VAT regardless of the intervention applied. When expressed as percent change in VAT/percent change in body fat, a ratio can be calculated which we call the Selectivity Index (SI). When this index is applied to the literature reviewed, two observations can be made. First, the Selectivity Index is higher when baseline body fat is higher. Second, there is a direct relationship between the Selectivity Index and the baseline visceral fat ratio. These two observations suggest that individuals with greater visceral fat mass, either through an increase in the body weight or the propensity to store fat in the visceral depot, lose more visceral fat when adjusted to the loss of body fat. CONCLUSION: In conclusion, the Selectivity Index is useful to compare the ability of an intervention to specifically target the loss of AT. This simple index can serve as a benchmark for comparing intervention studies to each other.