I Am Starting To Take Levothyroxine And I've Been Reading

I am starting to take Levothyroxine and I've been reading what to avoid. It mentions not eating certain things within 4 hours of taking the med. I do take vitamins and other supplements that contain magnesium and also tums. I have been waiting for three or so hours to eat any of those things. I also read that walnuts and high fiber foods interfere with it's effectiveness. Do I avoid them altogether or just the 4 hours within taking the med?