The Caveman Diet, also known as the Paleo Diet, is a weight-loss craze where calorie-counters pick foods they think early humans may have eaten. For most followers, this means a meat-heavy diet.

A new GEICO ad shows a self-aware caveman waking up in the middle of the night and grappling with a reminder of what used to be. As part of the commercial, the caveman considers whether he wants ...