Disclosed herein are methods for treating obesity, metabolic syndrome, diabetes, or a combination of these conditions. The methods include selecting a subject with obesity, metabolic syndrome, or diabetes and administering to the subject a therapeutically effective amount of a composition comprising a compound that specifically inhibits hepatic protein kinase C (PKC)-τ, thereby treating the obesity, metabolic syndrome, or diabetes in the subject. In some embodiments the compound that specifically inhibits hepatic PKC-τ includes a thio-gold compound (such as aurothiomalate, aurothioglucose, and auranofin) or a derivative thereof, or a pharmaceutically acceptable salt thereof. In other embodiments, the compound that specifically inhibits hepatic PKC-τ includes 1H-imidazole-4-carboxamide, 5-amino-1-[2,3-dihydroxy-4-[(phosphonooxy)methyl]cyclopentyl]-[1R-(1α,2β,3β,4α)] (ICAPP) or a derivative thereof, or a pharmaceutically acceptable salt thereof.
