The Alkaline iet (also known as the alkaline acid diet and the acid alkaline diet) is a controversial dietary protocol based on the consumption of mainly fresh fruit, vegetables, roots and tubers, nuts, and legumes and avoiding grains, dairy, meat and excess salt, in order to balance the acidity and alkalinity (the "pH balance") of one's body. In recent years it has been a popular topic among authors of diet and nutrition. The common belief among most medical practitioners, however, is that the blood alkalinity (pH) is not significantly affected by diet, except for pathological cases (e.g., of ketoacidosis produced by diabetes). Without well designed human research studies showing that these diets actually do what they say they can, qualified dietitians, nutritionists and other health care professionals have not recommended these diets to their patients.