In light of the aging population, effective policies to prevent the loss of independence are becoming a top priority for the coming years. Numerous international studies highlight the link between adopting healthy behaviors in midlife (ages 40–64) and healthy aging. Expert consensus calls for the implementation of earlier preventive measures starting at age 40, whether to prevent dementia or to delay the onset of chronic diseases leading to loss of independence in old age. In this context, Santé publique France has decided to launch a new program titled "Healthy Aging," in which the monitoring of diseases and health determinants will integrate the various dimensions of health (physical, mental, and functional) and prioritize prevention and health promotion efforts in midlife. In this report, following a review of the health challenges associated with aging (increased burden of chronic diseases), we provide an epidemiological overview of the various chronic conditions linked to loss of independence during aging, supplemented by a description of the main risk factors for these conditions, which are already common by midlife. While the temporal dynamics of the various conditions described in this report (cardiovascular disease, diabetes, chronic respiratory diseases, dementia, etc.) are heterogeneous, the aging of the population will in itself contribute to an increase in the prevalence of all these conditions. The current state of health among the French population aged 40 to 64, meanwhile, reveals numerous concerning indicators linked to the onset of disability at an older age. This is particularly pronounced among people of lower socioeconomic status. The results of observational studies demonstrate the beneficial effect of adopting protective health behaviors on aging—and the situation in France in this regard—in terms of the prevalence of modifiable risk factors. They strongly support the implementation of comprehensive, multi-determinant prevention strategies starting in midlife, some of which must continue throughout life.