To study and analyze the impact of socio-economic factors on secular changes in height, weight, and body mass index (BMI) among Moscow's youth over the time interval from the late 19th-early 20th century to the present. Anthropometric data, including height, weight, and BMI, were collected through surveys conducted on youths aged 17-20 years in Moscow from the 1880s for males and from the 1920s for females to the present. The dataset includes information on 6434 individuals surveyed from 2000 to 2019, as well as previously published mean values. Economic development indicators, such as gross domestic product (GDP) per capita, monthly average income per capita, and the Gini coefficient, were examined to analyze the association between secular trends in body size and socio-economic conditions. A positive secular trend in height and weight has been observed among Moscow's youth from the early 20th century to the present. Substantial increases in height occurred during the second half of the previous century, stabilizing in the 2000s. Over the analyzed period, both average body weight and BMI values showed a consistent rise. The pattern for BMI exhibited a U-shaped trend, with a decline from the 1970s to the mid-1990s, followed by a subsequent increase. Strong correlations were found between the secular changes in body size among Moscow's youth and temporal fluctuations in key socio-economic indicators, including GDP per capita, monthly average income per capita, and the Gini coefficient. The study demonstrates the significant influence of socio-economic conditions on intergenerational changes in body size, as evidenced by the positive secular trend in physique indicators (height, weight, and BMI) among Moscow's youth.