Extending life is only part of the goal in aging research. Scientists also want more people to reach old age in good health, with fewer differences in when individuals die. This ideal outcome is often described as “squaring the survival curve,” where most deaths are pushed into a narrow window late in life rather than spread out across many years.
To test how close current science comes to that goal, University of Sydney researchers revisited a large meta-analysis of studies in vertebrates. They focused on three widely studied interventions: dietary restriction, rapamycin, and metformin. While all are linked to longevity, they work in different ways.
Dietary restriction involves reducing calorie intake without causing malnutrition. It has been known for more than a century to extend lifespan in animals and is thought to act in part by dialing down a key cellular growth pathway called mTORC1, which helps regulate metabolism and aging. Because strict diets are difficult to maintain, scientists have searched for drugs that mimic these effects. Rapamycin directly blocks mTORC1 activity, while metformin, a common diabetes medication, influences the same pathway indirectly by altering how cells sense energy levels.
