Meet Grok. According to his online profile, he is a tall, lean, ripped and agile 30-year-old. By every measure, Grok is in superb health: low blood pressure; no inflammation; ideal levels of insulin, glucose, cholesterol and triglycerides. He and his family eat really healthy, too. They gather wild seeds, grasses, and nuts; seasonal vegetables; roots and berries. They hunt and fish their own meat. Between foraging, building sturdy shelters from natural materials, collecting firewood and fending off dangerous predators far larger than himself, Grok's life is strenuous, perilous and physically demanding. Yet, somehow, he is a stress-free dude who always manages to get enough sleep and finds the time to enjoy moments of tranquility beside gurgling creeks. He is perfectly suited to his environment in every way. He is totally Zen.

Ostensibly, Grok is "a rather typical hunter–gatherer" living before the dawn of agriculture—an "official primal prototype." He is the poster-persona for fitness author and blogger Mark Sisson's "Primal Blueprint"—a set of guidelines that "allows you to control how your genes express themselves in order to build the strongest, leanest, healthiest body possible, taking clues from evolutionary biology (that's the primal part)." These guidelines incorporate many principles of what is more commonly known as the Paleolithic, or caveman, diet, which started to whet people's appetites as early as the 1960s and is available in many different flavors today.

Read more at Scientific American.