The present invention relates to a method of treating a fatty acid synthesis related disease comprising administering to a patient in need thereof an effective amount of a PARP inhibitor or metabolite thereof to inhibit fatty acid synthesis, wherein the fatty acid synthesis related disease is obesity, diabetes, or cardiovascular disease. The present invention also relates to a method of treating a cancer in a subject comprising: (i) identifying a level of fatty acid in a sample from the subject, and (ii) administering an effective amount of a PARP inhibitor or metabolite thereof to inhibit fatty acid synthesis in the subject, wherein the administration is based on the level of fatty acid, thereby treating the cancer in the subject. The present invention further relates to a method of treating Her-2 related cancers by administering to a patient in need thereof an effective amount of a PARP inhibitor or metabolite thereof to inhibit fatty acid synthesis.
