In The Structure of Scientific Revolutions, Thomas Kuhn noted that scientific discovery is never complete; it goes through predictable stages of evol… - David A. Sinclair

THE THREE MAIN LONGEVITY PATHWAYS, mTOR, AMPK, AND SIRTUINS, EVOLVED TO PROTECT THE BODY DURING TIMES OF ADVERSITY BY ACTIVATING SURVIVAL MECHANISMS. When they are activated, either by low-calorie or low-amino-acid diets, or by exercise, organisms become healthier, disease resistant, and longer lived. Molecules that tweak these pathways, such as rapamycin, metformin, resveratrol, and NAD boosters, can mimic the benefits of low-calorie diets and exercise and extend the lifespan of diverse organisms.

Bill Gates made a convincing argument for why improving human health is money well spent, and won't lead to overpopulation, in his 2018 video "Does Saving More Lives Lead to Overpopulation?"56 The short answer is: No.
If we were to stop all deaths — every single one around the globe — right now, we would add about 150,000 people to our planet each day. That would be 55 million people each year. That might sound like a lot, but it would be less than a single percentage point. At that rate, we would add a billion people to our ranks every eighteen years, which is still considerably slower than the rate at which the last few billion people have come along and easily countered by the global decline in family sizes.
It's still an increase, but it's not the sort of exponential growth many people fret about when they first encounter the idea of slowing aging.
Recall, these calculations are what we'd face if we ended all deaths right away. And although I'm very optimistic about the prospects for prolonged vitality, I'm not that optimistic. I don't know any reputable scientist who is.

Even if they don't recognize its violence, children come to understand the tragedy of death surprisingly early in their lives. By the age of four or five, they know that death occurs and is irreversible.2 It is a shocking thought for them, a nightmare that is real. A "GOOD, LONG LIFE." My grandmother "Vera" sheltered Jews in World War II, lived in primitive New Guinea, and was removed from Bondi Beach for wearing a bikini. The end of her life was hard to watch. "This is just the way it goes," she said. But the person she truly was had been dead many years at that point. At first, because it's calming, most children prefer to think that there are certain groups of people who are protected from death: parents, teachers, and themselves. Between 5 and 7, however, all children come to understand the universality of death. Every family member will die. Every pet. Every plant. Everything they love. Themselves, too.