Shower thought: if PCOS or hypothyroidism or [insert condishun here] makes it impossible to lose weight with a calorie deficit, that sure would be welcome news to all the starving women in Africa who have no modern medical treatment whatsoever for PCOS, hypothyroidism or fibromyalgia.  Since conditions break the laws of physics, they clearly have nothing to worry about after all, especially since their metabolism will just go into starvation mode to prevent weight loss!