It’s debatable whether the Last Supper was a Passover meal or not. In fact, at least one of the Gospels makes a big deal about how they rushed the Crucifixion to get it over with before Passover started that evening. That was a Friday, so Thursday night couldn’t have been a Passover meal. Therefore, a number of Christian theologians assume that the bread was leavened, and for them, the symbology pairs with that of the wine: both in yeast bread and in wine there is human effort and also a mysterious transformation (leavening in the first, fermentation in the second) that symbolizes how the Holy Spirit works in people. Take the thought for what it’s worth.
Personally, I have found that you can’t stop people from eating carbs any more that you can stop people (sometimes the same people!) from sinning. I’m not sure it’s my place even to try. I have a strong moralistic streak that needs to be kept under control or I start telling the world what to do, and for some reason most people find that annoying. (That said, you’d all be in a lot better shape if you’d just listen to me and do things my way, lol!)
I don’t worry about Communion because the quantities are so small. And given the wafers they use in the parish where I work, it doesn’t trigger my carb addiction because (as one humorous bishop put it) it takes more faith to believe it’s bread than to believe it’s the Body of Christ. Likewise, over years of sobriety I have perfected the art of taking the tiniest sip of the wine. As a priest friend of mine put it, it’s the Blood of Christ, but it can still get me drunk, so I am always careful. And I never partake if I think one of my addictions is going to be triggered that day. God may not want me in the thrall of addiction, but he’s also not about to save me from deliberate stupidity on my part, lol!
For those worried about the consequences of partaking, I can assure you that the ancient tradition is that receiving Communion in one element only (whether bread or wine) is just as valid as receiving both, and there is even a tradition that, when bringing Communion to the sick, if medical reasons prevent the patient from receiving the Elements physically, the spiritual benefits of Communion are still transmitted. Surely this principle also applies to ketonians, as well. We can trust that God understands and does not niggle about these things as we do. The Sacrament is there to bless us, not to torture us.