Along those lines, there was a time when I was feeling physically challenged. Ghee and sugar and some of the general fare seemed too heavy for me and would make me sleep or get sick. When I ate light foods, I would be healthy. Devotees told me, "That's maya. If you take prasadam, Krishna will bless you. Whatever you get is just a tiny fragment of your karma. Devotees eat prasadam and don't worry about health food."
That was philosophically sound, but practically speaking if I ate a light diet I served better and had a clearer mind. I asked, "Srila Prabhupada, I understand the principle of accepting Krishna's mercy by taking prasadam, but when I eat light it's easier, when I eat heavy it's difficult. What should I do?" I was ready to do whatever he told me. He said, "If you're Rupa Goswami you should just take prasadam. But if you are a neophyte, which all of you are, you have to decide what is good for your devotional service and what is not good for your devotional service."
Then I asked him, "If I'm feeling sick and I need to eat something other than what's offered to the Deities, how do I offer it? How do I feel like I'm taking prasadam?" He said, "If you need to prepare something simpler than what's being prepared for the Deities, you prepare it at the same time the Deity offering is being prepared and set it aside. It doesn't go on the altar but it's set aside, and after the offering is over it's also offered. But you can't make preparations more opulent than Krishna's offering. If you have to take simple foods, you can do it that way. But don't make opulent dishes without offering them."