11-beta-Hydroxysteroid Dehydrogenase Type 1/metabolism; Dietary Fats/administration & dosage; Fatty Acids/administration & dosage; Gene Expression Regulation, Enzymologic; Intra-Abdominal Fat/metabolism; 11-beta-Hydroxysteroid Dehydrogenase Type 1/genetics; Animals; Body Weight; CCAAT-Enhancer-Binding Protein-alpha/genetics; CCAAT-Enhancer-Binding Protein-alpha/metabolism; Dietary Fats/adverse effects; Dietary Fats/analysis; Fatty Acids/adverse effects; Fatty Acids/analysis; Fatty Acids, Unsaturated/administration & dosage; Fatty Acids, Unsaturated/analysis; Female; Insulin Resistance; Liver X Receptors; Metabolic Syndrome/epidemiology; Orphan Nuclear Receptors/genetics; Orphan Nuclear Receptors/metabolism; Palm Oil; Plant Oils/administration & dosage; Plant Oils/adverse effects; Plant Oils/chemistry; RNA, Messenger/metabolism; Rats; Rats, Inbred F344; Reverse Transcriptase Polymerase Chain Reaction; Sunflower Oil; Trans Fatty Acids/administration & dosage; Trans Fatty Acids/adverse effects; Trans Fatty Acids/analysis