I had the flu last week. I made soup with chicken broth, meat from rotisserie chicken, a little broccoli and I sliced up a lowcarb wheat tortilla and put it in last. It was really good and made me feel better. I bought a packet of spices and made egg drop soup. It has protein from the egg and the broth and green onion were good too, only 5 carbs. I took Zinc plus tablets, their great for killing the germs in your throat, it also echinecea and vit C and stuff. Everytime I took one I would feel completely healthy for a few hours.

I also had some big glasses of diet sprite to get extra liquids.

I think you can stay lowcarb and will be just fine. If you need an extra treat for being sick have some lowcarb candy or ice cream.