At the homepage of the ISO-diet, the founder Fredrik Paulun with a Masters in Nutrition, compares six different diets. He claims the following about low carb:
"Ketone bodies are formed in the body when on a low carbohydrate diet. Ketones are acidic and makes the environment in the body more acidic, which increases the risk for brittle-bone disease, inflammation, constipation and pain. The brain also doesn´t function as well, with a lower carbohydrate intake and you lose interest in exercise. Simply put, it makes you stupid."Link for those who read Swedish: http://www.isodieten.se/Publikt/Dietjamforelse
NOTE: This is not satire, even though it might make a few people laugh.
Also note that his claims are pure fabrication except for the constipation part which could be a transitional side effect of switching to a low carb diet.
The ISO-diet is Paulun´s baby - one of his businesses. Let´s all wish him best of luck with his business and his business methods. When a business owner has so little faith in his own method he relies on slandering the competition, well, that´s all that needs to be said of the owner and the method.