Effect of dietary walnuts on the levels of key proteins involved in lipid metabolism following exposure to HFD for 6 weeks. (A) Representative images of the immunoblot analysis for SIRT1, P-AMPK, AMPK, FAS or GAPDH in the livers of experimental mice. The densitometric levels of (B) SIRT1, (C) P-AMPK, and (D) FAS measured by immunoblot analysis were normalized to GAPDH are shown. The densities of all samples are presented as mean ± SEM. Significance was determined by one-way ANOVA with the Tukey’s post hoc test (P<0.05) and is denoted by different letters.