High protein diets cause the liver and kidneys to work harder to process and excrete nitrogen and ketones. High protein diets provide excessive intakes of cholesterol, fats, and saturated fats. High protein diets are not advocated by many credible health organizations. Research supporting the benefits of high protein diets has not been published in respected medical or nutrition journals. It is not natural to assume that all medical or health professionals have a good nutrition background.
Nutrition is a complex specialty and can be studied briefly or extensively.
An extensive knowledge of nutrition is necessary in order to evaluate dietary recommendations. Trainers and physicians may have taken a few courses in nutrition or even none at all. Registered Dietitians or R.D.'s are nutrition experts who have completed a minimum of a bachelor or masters degree in nutrition, a 900-hour clinical internship, and passed a national credentialing examination. They are required to maintain continuing education in nutrition and are governed by the American Dietetic Association. Don't forget the big picture.