Changes in subcutaneous fat cell volume and insulin sensitivity after weight loss.
Level 4 - case-series / case-control
Prospective single-arm before-and-after study without an unoperated control group
PubMed 24760260 · doi:10.2337/dc13-2395
What was done
The authors evaluated 62 obese women before and 2 years after Roux-en-Y gastric bypass (RYGB). They measured abdominal subcutaneous adipose tissue fat cell volume and cell number, regional body fat mass using dual-energy X-ray absorptiometry (DXA), insulin sensitivity using hyperinsulinemic-euglycemic clamps, and plasma glucose, insulin, and lipid profiles.
What was found
RYGB reduced body weight by 33%, accompanied by decreased adipocyte volume but no change in adipocyte number. Measured regional fat mass and all metabolic parameters improved significantly post-surgery (P < 0.0001). Reduced subcutaneous fat cell size correlated strongly with improved insulin sensitivity (P = 0.0057), whereas regional fat mass changes did not, except for a weak correlation between changes in visceral fat mass and both insulin sensitivity and triglycerides. The curvilinear relationship between fat cell size and fat mass was significantly altered after weight loss (P = 0.03).
Why it matters
This indicates that shrinking the size of hypertrophic subcutaneous fat cells is a stronger determinant of post-bariatric insulin sensitivity improvements than bulk fat mass reduction alone.
Limits
The study included only women (n = 62) and lacked a non-surgical weight-loss or unoperated control group. The abstract does not report baseline or post-operative absolute values or confidence intervals for cell volume and insulin sensitivity metrics.
Cited by
- supports When weight is lost, adipocytes shrink in volume rather than being eliminated entirely.