The flu occasionally causes stomach upset, leading to nausea and diarrhea, so you may be tempted to stick to bland foods like pasta and rice. This is a good idea, but be mindful of how your tum handles it.

"You want to stick to easy to digest foods like simple [or] refined carbohydrates," Vavrek says. "Foods like dry saltine crackers, toast and pretzels are easy on your stomach and are most likely to be tolerated when you have the flu." That being said, Vavrek says, foods higher in fiber are also harder to digest, so you might want to avoid them at first. Wait until you're keeping food down before adding oatmeal into the mix.

You might think a vitamin C-rich fruit juice or an electrolyte-packed sports drink are the best things to drink while sick, but these options aren't terribly nutritionally dense.

Dr. David Kahana M.D., a board-certified gastroenterologist with supplement company 1MD, tells Bustle to raid the fruit bowl over the bottle. He particularly recommends "fruits that are rich in vitamin C and water and boost the immune system while providing essential electrolytes and antioxidants." A study in Nutrients in 2017 found that vitamin C plays an important role in your immune system's health, so get yourself some orange juice.

Between your elevated temperature and increased sweating, dehydration is something to be wary of when you have a fever. Stay away from diuretics like caffeinated coffee, which can contribute to dehydration.

"Avoid caffeine and alcohol as these can often make symptoms worse," Vavrek says. "You may also want to sip on water or other clear liquids throughout the day to stay hydrated."

Put down the hot toddy. Alcohol is a diuretic just like caffeine, and you don't want to play with dehydration when you have the flu. Scientific American reports that dehydration can dry up mucus in the throat, nose and mouth. In turn, this can make coughing difficult, according to American Family Care.

"The most important thing to do when sick with the flu is drink plenty of liquids, since it can be very dehydrating to have the flu and that makes things worse," Dr. Kahana says. "Drinking soup is one common food that people turn to, as it is rehydrating, comforting, and easy to digest."

Certain supplements like echinacea and zinc are touted as cure-alls, but there's little research to actually support these claims. Consumer Reports looked into the science behind popular supplements in 2017, and found that most supplements aren't really necessary. One supplement not to miss, though? Probiotics, says Dr. Kahana, "can help boost the immune system and stimulate digestion." A study published in mBio in 2020 found the flu can take a toll on your gut biome, so keeping it healthy with probiotics can make your overall digestion feel better.

Both Dr. Kahana and Vavrek say that greasy food is hard on the digestion and should be avoided while you're dealing with flu symptoms. "Avoid fried, greasy and oily foods as they are harder on your GI system," Vavrek says.

Dairy may not prolong your cold as your mom told you growing up, but it might make you uncomfortable. Although a review of the science published in 2019 in Archives of Disease in Childhood found that it doesn't actually promote mucus production, there's evidence that dairy makes your phlegm feel thicker and more irritating.