The reason there is a max on protein is that current nutrition practice does not endorse high protein intake for any reason. The Healthy Body Calculator® uses algorithms used in current nutrition practice and standards established by medical research.
While high protein diets temporarily result in weight loss, they usually don’t maintain long term loss. In fact, the yoyo effect of quick weight loss of low carbohydrate diets often results in re-gain once a person goes off a high protein diet and resumes their normal eating habits.
Carbohydrates you eat attract water in your body. When you store carbs as glycogen in muscle, carbs bring water into muscles. So, when you deplete stored muscle glycogen, you lose water. When you start eating carbs again, weight gain results from your muscles re-hydrating