Well really the old wivesí tale to feed a cold hops back to the time when most food was carb-loaded and of course the high rush of sugars that the body was flooded with was exactly what the cold viruses like to feed on.
As you're now moving towards low carb that is not such an issue. However your body still needs energy so you do really want to try and eat as much fat as you can and if you want something soothing for your throat then scrambled egg cooked in butter will be a good idea and I would suggest you have a good quality cheese melted into it to give you the fat as well.
Another thing thatís great is a ripe avocado with mayonnaise sprinkled with lots of cayenne pepper. Both the avocado and the mayonnaise will have a significant portion of fat and the cayenne pepper will also help to rid your body of the bugs.
Hope that helps,