When you have a fever, you may lose your appetite, but this doesn’t mean you should “starve a fever.” More research is needed to confirm if the saying “feed a cold, starve a fever” holds true.

“Feed a cold, starve a fever.”

There’s a pretty good chance you’ve been on the receiving end of this advice, or perhaps you’ve given it. After all, this bit of popular wisdom has been around for centuries. But is it true? Does this advice really hold any weight?

In this article, we’ll explore basic self-care for a cold, the flu, and fever. And we’ll look into whether fasting is really a helpful strategy to help you get back on your feet when you have a fever.

Several websites, including Smithsonian.com and Scientific American, say it can be traced as far back as 1574. Apparently, that’s when a dictionary writer named John Withals wrote, “fasting is a great remedy of fever.”

Wherever it came from, it has become firmly entrenched in popular culture, and is still a popular piece of advice today.

It’s not unusual to lose your appetite when you’re sick. At times, not eating seems to help, but sometimes it can make you feel that much weaker. So, should you really starve a fever?

Not according to the medical experts at Cedars-Sinai, who call it fiction. Cold or flu, your immune system needs energy and nutrients to do its job, so eating and getting enough fluids is essential.

Harvard Medical School agrees, saying that there’s no need to eat more or less than usual if you have a cold or flu. Both institutions stress the importance of fluids.

Colds and flu are usually caused by a viral infection, but a fever can happen for many reasons, including:

  • a bacterial infection
  • inflammatory conditions
  • side effect of some medications and vaccines
  • dehydration or heatstroke

So, that brings up the next question: Does it matter what’s causing the fever? Are there some types of fever that should be starved?

A 2002 study suggested that eating nutrient-rich broth may help fight viral infections, while fasting may help the immune system fight bacterial infections. It’s worth noting that it was a small study, involving only six young, healthy males. Study authors acknowledged the need for more research.

In a 2016 study, researchers also found fasting to be helpful in fighting bacterial but not viral infections. However, this study was conducted on mice, not people.

There simply hasn’t been enough “feed a cold, starve a fever” research done on humans to know for certain. It’s further complicated by the fact that there are so many causes of a fever.

So, it’s probably best to eat when your stomach can handle it and to go light on food when it can’t. Either way, it’s important to drink plenty of fluids to stay hydrated.

Colds and flu are both caused by viruses and they have common symptoms, like congestion and body aches. Flu symptoms tend to be more severe and involve fever.

Colds must run their course, but there are some things you can do to ease the symptoms.

  • Drink lots of fluids, but avoid caffeine and alcohol, which can lead to dehydration.
  • If you smoke, try to stop until your head clears up. Stay away from secondhand smoke if you can.
  • Use a humidifier to moisten the air.
  • Continue to eat healthy foods.

You can choose from over-the-counter (OTC) medications such as:

  • nonsteroidal anti-inflammatory drugs (NSAIDs) for relief of aches and pains, like ibuprofen (Advil, Motrin), naproxen (Aleve), or aspirin
  • a decongestant or antihistamine to clear your head
  • a cough suppressant to ease the symptoms of a cough
  • throat lozenges to help soothe a sore, scratchy throat

Take these medications according to package instructions. If you have any concerns about mixing OTC products or how they’ll interact with your other medications, ask your doctor or pharmacist.

If necessary, your doctor can prescribe stronger medicines to help control cough and congestion. Antibiotics do nothing for the common cold, since they don’t work on viruses.

Compared with a cold, the flu typically takes a lot more out of you, especially when you’re running a fever. You can try the same self-care measures as you would for a cold, plus:

  • See your doctor if you’re at risk of complications due to a weakened immune system or conditions like asthma, heart disease, or diabetes.
  • Take antiviral medications if prescribed.
  • Get plenty of rest. Don’t go to work or school until your temperature has been normal for 24 hours.

Because flu is caused by a virus, antibiotics won’t help. The exception would be when complications of the flu lead to a secondary bacterial infection.

Even if you don’t have much of an appetite, you need energy to fight the flu. You don’t have to eat as much as usual, but it’s important to choose helpful foods.

If you have nausea and vomiting, try a little broth and dry crackers until it passes. Vomiting and diarrhea can get worse if you drink fruit juices, so stick to water until your stomach is stronger.

If you’ve got a fever, it means your immune system is fighting an infection. A low-grade fever may go away on its own within a few days.

To treat a fever:

  • Stay hydrated with water, juice, or broth.
  • Eat when you feel hungry and your stomach can tolerate it.
  • Avoid bundling up too much. Although fever makes you feel chilled, overbundling can raise body temperature.
  • Get plenty of rest.
  • Take OTC NSAIDs.

If you have a fever that lasts more than a few days, see your doctor. Whether it’s the flu or not, you may need more than home remedies.

Most people don’t need to see a doctor for the common cold or a mild bout of the flu. Call your doctor if your symptoms last more than a week and there’s either no sign of improvement, or if your symptoms start getting worse.

Also, call your doctor if your temperature is 103°F (39.4°C) or higher, or if your fever is accompanied by:

  • a severe headache, light sensitivity
  • stiff neck or pain when you bend your head forward
  • new or worsening skin rash
  • persistent vomiting, abdominal pain, or pain when urinating
  • breathing problems or chest pain
  • confusion, convulsions, or seizures

Research has yet to confirm the centuries-old adage “feed a cold, starve a fever.” One thing we know for sure is that when you’re sick, staying hydrated is crucial.

We also know that your body needs nutritional support to fight illness. So, if you have a fever and you haven’t lost your appetite, don’t deprive yourself. Try to focus on eating foods that will give your body the nutrients it needs to get better.

When in doubt about what to do for a fever, talk to your healthcare provider.