Well, you're stronger than me. You probably know by now how your body responds to food.
I can see a case against going low carb. Carbs are supposed to be "muscle sparing." I have no idea what that means. I just figured if you're inactive, you won't need that many carbs. That, and if you can't forcefeed yourself per usual, then eating fat will be a more efficient way to gain calories than eating carbs. I don't think you'll gain weight unless you eat like a total pig and get drunk every other day. Who knows, maybe having a diet where you switch carbs with fats will increase your hormone levels and reduce catabolism.
I have no doubts that no matter what you lose, you'll gain it back. I was just thinking that your muscles won't be fatigued so you won't need many carbs to replenish them, nor will you need many carbs for energy either. When you cycle your carbs, you eat more carbs and slightly less protein on your most intense training days. Those are your 'high days.' on your 'low days' or your rest days, carbs are down and protein is up. Since you won't be doing anything, you're about to have a bunch of 'low days.'
I have no idea what good L-Leucine will do if your inactive. Maybe it will do some good and maybe it won't. It's supposed to be the specific trigger for new muscle growth: something you won't be experiencing over the next two weeks. If I had a big, expensive tub of that stuff, I'd just save it for when I get back to training. To me it seems like taking L-Leucine while inactive is like taking Spike while inactive - it doesn't make any sense and it won't do you any good.
But maybe I'm totally wrong about L-Leucine. Thibs just underwent surgery and he wrote about that in the L-Leucine release article. I forget if he said he used it after he got out of the hospital to put his muscle back on or if he took L-Leucine while he was in the hospital to minimize muscle loss. Don't take my advice. Go read that article and see what Thibs did. If he started taking the L-Leucine AFTER he got out of the hospital, then I'd keep the lid closed until I was ready to train.