Literary giant Walt Whitman was an early advocate of what today sounds like the popular paleo diet, according to the author’s recently uncovered writings. “Let the main part of the diet be meat, to the exclusion of all else,” Whitman wrote, according to a New York Times report. The advice is part of a 47,000-word series advising readers on how to live a healthy life that the poet published in the now-defunct New York Atlas in 1858.