Cooper is mostly unfazed by critics or negativity, but there have been plenty of people who tried. Daily Mail Australia featured a well-known dietitian Dr. Rosemary Stanton, who publicly stated that she doesn't believe the diet is a good idea.
She reasoned how "It's really not usually a good idea to put a child on such a restricted diet, particularly when there's no valid grounds for it... Depriving her child of grains and legumes will make it much more difficult to achieve a balanced diet... I'd certainly sound a note of caution (to other people considering following her)."