Low carb, high protein.
The stones could be the result of ketosis.
Most stones are the result of excess calcium or phosphorous in the diet. “excess” being defined by the bodies abilty to absorb / dispose of the total intake. The total intake is highly veriable and one of the major factors is the hydration level of the individual. Being in a state of ketosis is known to reduce the hydration level.
Individuals who are on a low carb diet should increase their water intake and take care to monitor their hydration.
The idea of the diet was not to maintain ketosis long term.
Low carb is not high protein; it’s high fat. God bless Dr. Atkins.
Fat without carbs is harmless. Fat with carbs is deadly.