The article describes the features of energy metabolism and vitamin D levels in elderly people with such conditions as sarcopenia and sarcopenic obesity. Purpose of research. To study the energy metabolism and peculiarities of vitamin D levels in the older human body in sarcopenia and sarcopenic obesity. Material and methods. The study included 162 elderly people aged 65 to 74 years, including 72 men and 90 women, the average age of patients was 69.2+3.4 years. All the people included in the study were measured anthropometrically. The results of the study were interpreted in accordance with the recommendations of the European working group on osteoporosis and sarcopenia (2009). All the people included in the study were taken blood samples. The state of the body was assessed on the basis of biochemical parameters of blood: the content of adenosine triphosphate (ATP), adenosine diphosphate (ADP) and lactate dehydrogenase (LDH). Energy metabolism was studied at rest and after induced stress. The level of basic metabolism (kcal/day) was determined. Blood test for vitamin D level was determined in autumn and spring. Results and discussion. We found that in sarcopenic obesity, the situation was significantly worse with respect to energy metabolism than in sarcopenia syndrome, due to a significantly more significant decrease in both ATP nucleotide and ADP. It was also shown that in people with obesity to compensate for energy deficiency by increasing the processes of glycolysis, which is manifested by an increase in the activity of the enzyme LDH, but with sarcopenia and sarcopenic obesity, this sanogenetic compensation mechanism is depleted. We have obtained data that in women, as in elderly men, vitamin D deficiency in sarcopenia syndrome and sarcopenic obesity is significantly higher than in people without sarcopenia or obesity. Summary. The article proves that in case of sarcopenia and obesity there is a deficit in high-energy phosphate bonds, which indicates the presence of an energy deficit state, reaching a maximum in people with sarcopenic obesity. In response to stress, healthy elderly people react with a natural increase in the level of basic metabolism (by 11.2% on average), while people with obesity and sarcopenic obesity show a paradoxical decrease (by 12.6% and 7.2%, respectively). Women and older men during the summer, vitamin D deficiency in the syndrome of sarcopenia and obesity crackopening practically eliminated. While in people without sarcopenia and with obesity, the prevalence of vitamin D deficiency in the autumn is significantly reduced compared to in the spring, on average by 13.9% in people without sarcopenia and by 33.2 %.