Would increasing calories (slightly) during a cold/flu/sinus scenario help with recovory. I think this would be along the lines of recovoring from a work out. I feel that most peaple seem to want to eat more when run down whether that be from overtraining or getting sick (which are not much seperated anyway).
In a fever situation I definently think not eating or eating very little for a couple of days during a fever would help it run its course and allow the body to acutely fight of whatever is causing the fever, much like a fast can increase autophagy and other benifits. Again it seems that most peaple with a fever just dont feel like eating at all.
While the first answer to come to mind is 'its going to be up to the individual', what merits do you think the old meme has.
EDIT:
To be clear, i'm not really concerned with what the saying may or may not have meant. I'm asking whether you think it would be a non-issue or even benificial to fast or restrict food during a fever, in light of research on immune system function and fasting/eating, as well as most peaples reaction to lose their appetite.
For the 'cold' side of things, either eating your normal diet or even increasing calories (perhaps quality carbs) to aid in recovory