LIVER METABOLIC EFFECTS OF A HIGH-FAT LOW- CARBOHYDRATE DIET IN RATS: A STUDY UNDER DIFFERENT ENERGY CONDITIONS

Resumen

The beneficial effects of high-fat, low-carbohydrate (HFLC) diets on glucose metabolism
have been questioned and its effects on liver metabolism are not totally clear. This work
aimed to evaluate the HFLC diet effects under different energy conditions on glucose
homeostasis, fatty liver development and hepatic gluconeogenesis using the isolated perfused
rat liver. HFLC diet (79% fat, 19% protein, and 2% carbohydrates in Kcal%) was
administered to rats over four weeks under three conditions: hypercaloric; isocaloric and
hypocaloric (energy reduction of 20%). Fasting blood glucose levels and total fat in the liver
were higher in all HFLC diet rats. Oral glucose tolerance was impaired in isocaloric and
hypercaloric groups, although insulin sensitivity wasn´t altered. HFLC diet also caused
marked liver metabolic alterations: higher gluconeogenesis rate from lactate and a reduced
capacity to catabolize alanine, the latter effect more intense in the hypocaloric condition. We
concluded that, even when HFLC diets are used for weight loss, our data imply that they can
potentially cause harmful consequences for the liver.