Potatoes can be okay on a daily basis, depending on how your body responds to them. If you have blood sugar issues, they may be more of a problem. There should be no interference or blocking of the effect of your medicines. As your body improves it's ability to absorb nutrients, and everything else, through your digestive tract on the Plan, you may find that the medicines have a greater effect with lower and lower doses. This is what we commonly see and people report to us and the reason why people are able to gradually lower the dosages of meds.