Who wants to live to 100 on a diet of lentil and broccoli slurry? Mostly rich men | Gaby Hinsliff

Instead of searching for the key to immortality, what if we tried to make people's lives better in the here and now?

Shortly after waking, Bryan Johnson drinks a murky concoction involving olive oil, cocoa flavanols and something derived from algae. Breakfast will be a blended green slurry of lentils, broccoli and mushrooms, with lunch and dinner not much different.

The 45-year-old American entrepreneur is religious about his sleep, follows a strict workout regime, monitors the performance of his vital organs using hospital-grade medical equipment, and suggests to his social - media followers that deviating from what he calls the blueprint" to have a raucous night out getting wasted with friends is a form of self harm.

Gaby Hinsliff is a Guardian columnist