Here is a list of the known reasons for aging, combining 12 of the best-supported 1 with 6 additional emerging factors that are under investigation (and what you can do about each):
Caloric restriction: Proven in multiple species to enhance longevity by affecting nutrient-sensing pathways like mTOR and IGF-1.
Chronic over-nutrition contributing to metabolic overload, oxidative stress, and insulin resistance, which may accelerate aging. 19
This list represents a comprehensive view of the known biological mechanisms and emerging factors contributing to aging. While the first 12 are strongly established in empirical research, the final 6 are under ongoing investigation and may gain further support as our understanding of aging evolves (or may fall off the list). As significant new information becomes available, I expect to update and republish this post. So, stay tuned.
Causes of genome instability: the effect of low dose chemical exposures in modern society - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4565613/