Your question has clearly to do with, finding more alternatives to low carb diet rather than just simply seeking an answer "do I have to really go for the low carb diet, sure???"
Let's quote the verse first,
O you who believe! Approach not As-Salat (the prayer) when you are in a drunken state until you know (the meaning) of what you utter, nor when you are in a state of Janaba.........Truly, Allah is Ever Oft-Pardoning, Oft-Forgiving. (Qur'an 4:43)
You're focusing on "drunken state" but also plz feel free to focus on "until you know of what you utter". If even while being inebriated, if you know what you utter, then its fine. I don't know what it feels like for the person who's suffering. If he/she feels very high then obviously going for the best possible alternatives present today i.e. low carb diet should be the top priority. Else, if he/she manages well enough to focus on the Salah and what he/she is uttering, then there wouldn't be necessary for a low carb diet.
But I think, there is something to do with the quantity (up to which extent) of the low carb diet, rather than completely 'yes' or 'no'.
Please note that, "Allah doesn't lay burden more than a person can bear", and "Allah is Oft Forgiving and he pardons much" if you do things during exceptions (only after proper consultation with the community) there shouldn't be any problem. So, until deemed necessary to discontinue, following the low carb diet in accordance with Qur'an 4:43 (as discussed above) must be given the top priority until the doctors come up with something new & Halal and more friendly.
May the creator guide us all.