Tech execs like Bryan Johnson and Sam Altman are optimizing their diets to live longer. Here's what experts say to eat to expand your lifespan, from pomegranates to red onions.

Pomegranates are high in Urolithin A, a compound that is known to improve mitochondrial efficiency.Oli Scarff/Getty Images

• As a quest for longevity sweeps the nation, people are taking supplements and prescription pills to reverse aging.
• Research shows that diet also plays a role in determining — and even increasing — a person's lifespan.

Some billionaires, like Elon Musk, opt for a donut for breakfast and barbecue for dinner.

Others, like biotech entrepreneur Bryan Johnson, methodically prepare smoothies with compounds like creatine, spermidine, collagen peptides, and consume copious amounts of vegetables.

Tech billionaires clearly don't have similar diets, or even goals for their health. Still, those like Johnson aren't abiding by fastidious nutrition plans simply to stay healthy — they're aiming to live longer.

And though there's certainly an overlap between eating for general health and eating for longevity, Dr. Anant Vinjamoori, chief medical officer of longevity-focused healthcare company Modern Age, told Insider there are also a few key differences.

Vinjamoori suggests looking at protein intake as an example.

"Protein is essential for building and maintaining muscle mass, and having adequate muscle mass is important for healthy aging." At the same time, Vinjamoori said, "protein intake is also known to work against some of the beneficial, restorative pathways in our body."

That idea is corroborated by the work of Dan Buettner, who founded the longevity brand Blue Zones.

Buettner spent years studying the habits of those in what are called "Blue Zones," regions of the world where people tend to live to the age of 100.

Across all five Blue Zones — Loma Linda, California; Nicoya, Costa Rica; Sardinia, Italy; Ikaria, Greece; Okinawa, Japan — Buettner and his team found that people consume less protein (especially animal protein) than the rest of the world.

David Sinclair, a Harvard Medical School professor and longevity researcher, takes the argument against animal protein one step further, contending that the best way to live longer is by dropping meat entirely.

In an interview with The Knowledge Project Podcast last December, Sinclair said that high animal protein diets may help people look and feel great, but only in the short term.

"I'm convinced, and the data shows it from population studies, that a carnivorous diet is not a longevity producing diet in the long run," he said.

Several powerful figures in the tech industry don't eat meat either. OpenAI's Sam Altman is vegetarian while Twitter co-founder Biz Stone is vegan.

Vinjamoori said that it can also be helpful to think about eating for longevity from the cellular level.

"I start with the question of what cellular processes I want to optimize, determine which compounds have been shown in research to optimize those processes, and then to find foods that have high concentrations of those compounds," he said.

Insider set out to figure exactly which foods would optimize those processes, and ultimately, help you live longer. Read more, below.