The popular advice to "feed a cold, starve a fever" is probably something you’ve heard time and again when nursing a cold or the flu. But is it advice you should heed?
The answer is no. In actuality, you should feed both a cold and a fever — and starve neither, says Mark A. Moyad, MD, MPH, Jenkins/Pokempner director of preventive and alternative medicine at the University of Michigan Medical Center in Ann Arbor.
“When you have a cold or a fever, your immune system is fighting off an infection, and eating less during the early stages of an infection can actually be dangerous,” he explains. “The body requires large amounts of energy to create and assemble the large number of immune cells necessary to fight the enemy. Good nutrition and calories provide this energy."
That’s especially true for people with less robust immune systems (such as very young children, the elderly, and people with chronic conditions, such as diabetes or cancer, or autoimmune disorders, like lupus or rheumatoid arthritis), who may suffer more serious colds and infections if they take in too few high-quality nutrients, Dr. Moyad says.
Does that mean you should force yourself to eat big meals when you’re sick? Again, the answer is no. There’s no need to eat more or less than usual, according to Harvard Health Publishing, but what you do eat should be rich in essential vitamins and minerals such as vitamin C and zinc.
The Age-Old Cold-and-Flu Adage That’s Actually True
Eating a bowl of chicken soup really can help you feel better when you’re battling an upper respiratory tract infection, research has shown. One classic University of Nebraska Medical Center study published in the journal Chest suggests that traditional chicken soup made with vegetables contains many beneficial substances that help ease inflammation and other cold and flu symptoms.
Another study, published in the journal Rhinology, showed that consuming warm liquids “provided immediate and sustained relief from symptoms of runny nose, cough, sneezing, sore throat, chilliness, and tiredness,” according to the researchers. And even earlier research in Chest found that eating hot chicken soup made it easier to blow germ-carrying mucus out of your nose.
More importantly, soup is hydrating, and taking in lots of water, juices, or broth is crucial for preventing dehydration when you have a fever, says Soma Mandal, MD, an internist with the Summit Medical Group in New Jersey. “If you’re dehydrated on top of feeling sick, that will make you feel worse,” she says.
One reason why is that during a fever, your body needs to use more fluids than usual to maintain different bodily functions, Dr. Mandal explains. For example, she says, “when you have an upper respiratory infection, the virus is replicating in the cells, which causes tissue damage. Hydration helps repair those cells.”
You also lose a lot of water as your body tries to release heat through sweat. So the higher the fever, the greater the risk of dehydration becomes. "If you have a high fever or a fever lasting more than two to three days, you will need even more fluids to keep from getting dehydrated," notes family medicine physician Curt Gingrich, MD, chief operating officer of OhioHealth Marion General Hospital in Marion, Ohio.
“In addition to making sure you’re drinking plenty of fluids during an illness,” Dr. Gingrich adds, “be sure to also get plenty of rest."