A serious definition would be a low carb diet with most protein from meat.  This would include lots of greens and a small amount of high fiber fruit.  In imagination, it is a traveling hero on an adventure, hunting game in the forest and fishing in streams and rivers on the way, and gathering berries and familiar greens to eat as well.  No time to plant high carb crops like wheat/corn and wait for a harvest. 

 Sounds fun 😊