Tongue colors come and go and are generally related to bacteria or yeast, and rarely trigger a response in doctors.
Most of the time its ignored.
Occasionally a yellow tongue is indicative of liver/gallbladder issues, and antifungals and antifungal-foods might be causing an overload of toxins for your liver to handle.
Going back to junk food would be giving your liver a rest from candida die-off, assuming there was any.
Thats my story and im sticking to it.