Sleeve gastrectomy did not change BAT weight (Figure 4b), but improved BAT morphology and function, as shown by the reduction in brown adipocyte hypertrophy (Figure 4a,c) and steatosis (Figure 4d), together with the repression of the transcription of the lipogenic genes Pparg2, Mogat2 and Dgat1 (Figure 4e–g). The gene discussed is PPARG; the disease is steatosis.