The Caveman or Paleolithic Nutrition Model:

Modern diets are ill suited for our genetic composition. Evolution has not kept pace with advances in agriculture and food processing resulting in a plague of health problems for modern man. Coronary heart disease, diabetes, cancer, osteoporosis, obesity and psychological dysfunction have all been scientifically linked to a diet too high in refined or processed carbohydrate. Search "Google" for Paleolithic nutrition, or diet, or read some of the published papers from www.thepaleodiet.com. The return is extensive, compelling, and fascinating. The Caveman model is perfectly consistent with the CrossFit prescription.