Aging, quite simply, is a loss of information. - David A. Sinclair

The longevity genes I work on are called "sirtuins," named after the yeast SIR2 gene, the first one to be discovered. There are seven sirtuins in mammals, SIRT1 to SIRT7, and they are made by almost every cell in the body. When I started my research, sirtuins were barely on the scientific radar. Now this family of genes is at the forefront of medical research and drug development. Descended from gene B in M. superstes, sirtuins are enzymes that remove acetyl tags from histones and other proteins and, by doing so, change the packaging of the DNA, turning genes off and on when needed. These critical epigenetic regulators sit at the very top of cellular control systems, controlling our reproduction and our DNA repair. After a few billion years of advancement since the days of yeast, they have evolved to control our health, our fitness, and our very survival. They have also evolved to require a molecule called nicotinamide adenine dinucleotide, or NAD. As we will see later, the loss of NAD as we age, and the resulting decline in sirtuin activity, is thought to be a primary reason our bodies develop diseases when we are old but not when we are young.

They have also evolved to require a molecule called nicotinamide adenine dinucleotide, or NAD. As we will see later, the loss of NAD as we age, and the resulting decline in sirtuin activity, is thought to be a primary reason our bodies develop diseases when we are old but not when we are young. Trading reproduction for repair, the sirtuins order our bodies to "buckle down" in times of stress and protect us against the major diseases of aging: diabetes and heart disease, Alzheimer's disease and osteoporosis, even cancer.

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.