Abstract. Objective: The aim of the work was to study the influence of fast-food and instant-food products on metabolic indicators and element status of laboratory animals. Materials and methods: The study was conducted on male Wistar rats. The experimental group consumed a semi-synthetic diet consisting of mixture of basic diet (50%), fast-food and instant food (50%). Total protein, ALT, AST, total bilirubin and triiodothyronine levels were assessed. The element composition of the liver was determined by atomic-emission and mass-spectrometry with inductively-coupled argon plasma. The activities of Cu, Zn-superoxide dismutase, and glutathione peroxidase were measured in erythrocyte lysate by spectrophotometric method. Results: A significant decrease in the content of a number of essential elements: Mn (3.6-fold), Se (1.21-fold), Si (3.6-fold), and Zn (1.25-fold) was observed. Al and Cd contents in the experimental group were significantly increased by a factor of 3.9 and 2, respectively. Consumption of fast-food products was accompanied by significantly lower values of total protein and greater activity of AST and ALT in serum. Activity of glutathione peroxidase (140.5 (121.0 – 151.0) U/mL) was significantly decreased (р = 0.000) in the experimental group in comparison to the control group (240.0 (229.0 – 251.0) U/mL).