I recently read the Art and Science of Low Carb Performance and the authors had done a metabolic ward study with a bunch of cyclists. Because they had to have precise measurements of all the food they ate, their kitchen would prepare only two different meals. One of those meals was a tuna salad with soybean mayo. The other one didn't have any crap oils, it was something more natural. One thing that surprised everyone was how after a while, each individual cyclist eventually came to them and said they couldn't stomach the tuna and mayo meal anymore. None of these cyclists ever knew each other or anything, but each and every one of them got sick of the mayo.
Whenever there's anything surprisingly miraculous about this diet, it's almost always the removal of crap vegetables oils. Usually, unless you have a real allergy, the reduction in carbs makes people feel worse not better, (better happens too, but not usually quite so quickly), but the change in fats usually makes people lose all their aches and pains, restore a mentally happy feeling and lots more. The oil is like a hidden killer.