a, Energy intake of HFD-fed control-ASO- and Nnmt-ASO-treated mice. b, Feed efficiency (body-weight gain per kilocalorie (kcal) consumed) of HFD-fed control-ASO- and Nnmt–ASO-treated mice. c, Fat mass gain per kcal consumed in HFD-fed mice treated with Nnmt ASO or control ASO. n =12 per group for a–c. d, Faecal lipid excretion (n =10 per group). e, Oxygen consumption (Vol. O2) measured by CLAMS (n =7 per group). f–h, Effects of a 16-h fast on body weight (f), fat mass (g), and lean body mass (n =8 per group) (h). i–k, Oxygen consumption in 3T3-L1 adipocytes transfected with control or Nnmt ASO (n =6 per group) (i), treated with 10 mM N1-methylnicotinamide (me-Nam) (n =6 per group) (j), or transfected with Nnmt cDNA (n =10 per group) (k). Error bars, ±s.e.m.; *P <0.05.