Adult rats (males) of the Wistar species and of SPF origin were studied for the dependence of frequency on the electric potential on EEG records of the region of the hypothalamic ventromedial nucleus and lateral hypothalamus of animals fed high-protein and high-fat diets. Similar values of control animals were used for comparison. Each group comprised seven animals. In the control animals, constantly fed the basic diet, the values of the frequency-voltage dependence remained unchanged. In the animals fed high-protein diet frequency increased with rising voltage whereas in those fed high-fat diet frequency declined with increasing voltage in both body regions under study.