Proponents of the paleolithic diet believe that human digestion evolved from the eating habits of our ancestors, therefore we should consume meat and produce exclusively—and ignore grains, dairy, and legumes. (Sorry, but archaeological findings regularly disprove the existence of such a meal plan.) Modern zealots trumpet it as a cure-all for everything from muffin tops to lethargy and depression. Not exactly. Meat is higher in artery-clogging saturated fat than plant-based protein sources, and cooking flesh over 300°F produces carcinogenic heterocyclic amines. Red meat, specifically, increases your risk of colon cancer by 17 percent for every
3.5 ounces consumed per day; the heme molecule, which helps turn it crimson, promotes growth of N-nitroso-compounds—another carcinogen. Cutting dairy and fiber-rich foods also messes with the microbial colonies that make our guts work. Without the probiotic benefits of yogurts and the prebiotic effects of fibrous foods (beans and whole grains), our tummies struggle to block pathogens, maintain metabolism, and extract calories and nutrients.