Encyclopedia entry
Visceral adipose tissue (VAT)
Visceral adipose tissue is the fat stored inside the abdominal cavity, wrapped around the internal organs (liver, pancreas, intestines). Distinct from subcutaneous adipose tissue, which sits between skin and muscle. VAT is metabolically active in ways subcutaneous fat is not: it releases inflammatory cytokines, raises hepatic insulin resistance, and is the dominant driver of cardiometabolic risk at any given BMI.
VAT vs subcutaneous fat
Two people can have identical BMI and different VAT levels. VAT is associated with type 2 diabetes, cardiovascular disease, non-alcoholic fatty liver disease, and several cancers. Subcutaneous fat (particularly lower-body) is largely metabolically inert and may even be mildly protective. This is why waist circumference (a rough VAT proxy) predicts risk better than BMI in many populations.
How VAT is measured
- · Waist circumference: cheapest proxy. Threshold of 94 cm (men) or 80 cm (women) for increased risk; 102 cm (men) or 88 cm (women) for high risk.
- · Waist-to-hip ratio: refinement; over 0.95 (men) or 0.85 (women) indicates central obesity.
- · DXA scan: estimates VAT specifically in some scanner models.
- · MRI or CT: gold standard for VAT measurement but rarely used outside research because of cost and radiation (CT only).
What GLP-1 does to VAT
GLP-1 weight loss is preferentially VAT-rich. Published imaging substudies from SURMOUNT and STEP trials show that VAT reduces disproportionately compared to subcutaneous fat at the same total weight loss. This is why cardiometabolic outcomes (blood pressure, HbA1c, ApoB, liver enzymes) often improve faster than scale weight suggests.
Why this matters for body recomp
Scale weight is a lagging indicator of cardiometabolic risk reduction during GLP-1 therapy. Waist circumference, VAT from DXA, and ApoB or HbA1c bloods all change faster than total weight. Tracking these alongside scale weight gives a better picture of metabolic benefit. Pure scale-weight focus understates the gains.
Related: DXA · ApoB · body recomp hub.