"It's hard to figure out exactly where this saying came from,"The Early Show medical correspondent Dr. Emily Senay told co-anchor Harry Smith. "It looks like it came from sometime in the middle of 1500s, but no one knows and I don't know which is the right way …There's not a lot of medical evidence to support either of these ways of saying this, so it's not clear at all."
She said not to challenge your immune system by either eating too little or too much but stay hydrated and eat in moderation.
"Until we have better evidence which one is right, I would shelve this saying," Dr. Senay said.
February is usually the month where the flu hits Americans the hardest. Dr. Senay said symptoms of the flu are more severe than most people think. If someone has the flu, he or she is not able to be up and walking around and definitely cannot go in to work. Symptoms include a high fever, body aches, extreme tiredness, dry cough, sore throat, runny or stuffy nose, diarrhea and vomiting — especially in kids.
"The real issue here is how quickly it comes on," Dr. Senay said. "One minute you're up and walking, the next minute you feel pretty lousy."
If someone has a cold, on the other hand, he or she can function but most likely feels a little off with a stuffy nose, sneezing, a cough, a scratchy throat and perhaps a headache. Dr. Senay said that if someone has a fever, it will be low-grade.
"The symptoms will come on over several days, peak and go away," she said.
Dr. Senay said that if someone has the flu, he or she should stay home from work and should not try to force themselves. If you really need to get to work, take some over-the-counter medication, but try not to interact with people.
"Not only is it bad for you because complications do occur with the flu, but all of your buddies at work — you're spreading that germ around," she said. "That's one germ you don't want to spread around."