Lifespan: Why We Age—and Why We Don't Have To

Six, she told us, was the very best age, and she did her damnedest to live life with the spirit and awe of a child of that age.

Aging is a disease. This is so clear that it seems almost insane that those four words need to be repeated again and again. But I’ll do so anyway: aging is a disease. And not only is it a disease, but it is the mother of all diseases, the one we all suffer from.

What’s the upward limit? I don’t think there is one. Many of my colleagues agree.14 There is no biological law that says we must age.15 Those who say there is don’t know what they’re talking about. We’re probably still a long way off from a world in which death is a rarity, but we’re not far from pushing it ever farther into the future.

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.

if we are to make real progress in the effort to alleviate the suffering that comes with aging, what is needed is a unified explanation for why we age, not just at the evolutionary level but at the fundamental level.

Often, we realize it too late. When it comes knocking, and we are not prepared, it can be devastating.

In the meantime, however, almost any periodic fasting diet that does not result in malnutrition is likely to put your longevity genes to work in ways that will result in a longer, healthier life.

She died at the age of 92. And, in the way we’ve been taught to think about these things, she’d had a good, long life. But the more I have thought about it, the more I have come to believe that the person she truly was had been dead many years at that point.

Indeed, it is a time in which we will redefine what it means to be human, for this is not just the start of a revolution, it is the start of an evolution.