Here's an open access paper for those of you interested in bioinformatics: using network theory and existing data on genes and proteins to predict new longevity genes and targets for further investigation. This is an example of the modern nuts and bolts of efforts to fully understand longevity from a reductionist point of view - a long road ahead there.
Identification of genes that modulate longevity is a major focus of aging-related research and an area of intense public interest. In addition to facilitating an improved understanding of the basic mechanisms of aging, such genes represent potential targets for therapeutic intervention in multiple age-associated diseases, including cancer, heart disease, diabetes, and neurodegenerative disorders.
We have utilized a shortest-path network analysis to identify novel genes that modulate longevity in Saccharomyces cerevisiae. Based on a set of previously reported genes associated with increased life span, we applied a shortest-path network algorithm to a pre-existing protein-protein interaction dataset in order to construct a shortest-path longevity network.
we report the identification of previously unknown longevity genes, several of which function in a conserved longevity pathway believed to mediate life span extension in response to dietary restriction.
I happen to think that the best near-term result - over the next decade, say - to come out of efforts aimed at complete understanding of our biochemistry will be a speeding of medical engineering for increased longevity. Engineering comes before science, and is improved by increased understanding provided by science, but you don't have to wait for full understanding to make progress. Bridge building was a fine art long before architectural and materials science became mature fields, and so too could longevity therapies be developed well in advance of a full understanding of metabolism. Medicine is, after all, a branch of engineering.
For an more detailed explanation as to why this is so, you might read up on the Strategies for Engineered Negligible Senescence. We already know more than enough to work at repairing our age-damaged biochemistry through medical science, as we can identify the precise ways in which old biochemistry differs from young biochemistry. Further understanding why these differerences exist will make the task of repairing them easier, but is not strictly necessary to progress. You don't need to know the chemistry of rust in order to perform the maintenance work of removing it from machinery - you just need to know how to remove rust.