Most of us have heard the adage “Feed a cold, starve a fever.”
It comes from an outdated theory that a cold makes your body cooler and eating can help warm it up, and that a fever makes your body warmer and fasting can help cool it down. The premise itself is flawed: While fevers do raise your body temperature, colds don’t make your body cold. You might even get a fever when you have a cold.
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As for whether you should eat more or less, in most cases, there’s no convincing evidence that limiting food intake when you’re sick plays a meaningful role in recovery, experts said.
There may be a more accurate approach. “Feed a cold. Feed a fever, too,” said Roy Gulick, the chief of the infectious-disease division at Weill Cornell Medicine and an attending physician at NewYork-Presbyterian Hospital.
Experts recommend staying hydrated and eating healthy foods – at least when your stomach will allow it – to support your body when you’re sick. The advice holds true whether you’re dealing with a cold, which is an upper-respiratory infection that can be caused by more than 200 viruses, or a fever, which can be caused by viral and bacterial infections, autoimmune issues and reactions to medications, among other things.
“If you are truly not feeling hungry, you don’t necessarily have to eat more than you feel like eating,” said Geeta Sood, an assistant professor in the infectious-disease division at Johns Hopkins University. However, you do want to make sure you’re getting enough calories, protein and nutrients – and hydration – to help support your body as it heals, she said.
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What does the research show?
Research in this area is limited – and mostly in animals. For example, in a 2016 study, mice were infected with either a bacterium that causes gastrointestinal illness or a virus that causes influenza. In mice with the bacterial infection, fasting was protective while nutritional supplementation was detrimental, the authors found. The pattern was reversed in mice with the flu and viral sepsis. While interesting fodder for further research, these results can’t be applied directly to humans, experts said.
In humans, researchers who conducted a 2021 review concluded that there is some evidence that nutrients such as vitamins and minerals can help support the body’s immune response and help fight infections in general. And a 2024 review that included newer studies that were conducted during the pandemic suggested that nutritional needs may depend on the specific pathogen you’re fighting and other variables, such as the duration and severity of your illness – not simply on whether it’s a bacterium or virus.
The reality is that most studies on how nutrition affects infections have looked at only a handful of pathogens, said David Schneider, a professor of microbiology and immunology at Stanford University. To further complicate matters, when you’re experiencing symptoms such as a runny nose or fever, you may not know whether you’re sick with a bacterium or virus, he said. Both of these things make it difficult to give generalized recommendations about what might be best for every cold or every fever, he said.
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Why do I lose my appetite when I’m sick?
There is some rationale to the adage, because it’s common to lose your appetite when your body is fighting off an infection. As your immune system ramps up, it releases chemical messengers, known as cytokines, to rally immune cells to fight infection, and those same signals also tell the brain that eating isn’t a priority, said Sharon Bergquist, an internal medicine physician and associate professor at the Emory University School of Medicine.
While not well understood, one theory states that a drop in calorie and protein intake triggers a process called autophagy, which helps recycle damaged cell parts and may play a role in immune defense, she said.
That said, the process of fighting an infection is “metabolically really costly,” Bergquist said, explaining that although you can skip food for a day if you aren’t hungry, going longer than that may leave you without adequate nutrition. “It takes so much energy and calories that there’s a rationale for us needing to increase our food and our hydration during times of illness so that we can support our immune system,” she said.
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What can I do if I have an infection?
Vaccines are the first-line defense to help prevent and lessen the severity of some viral infections, including covid and the flu. If you get sick, however, you can try some medications that may help you recover faster.
– Antibiotics target specific kinds of bacteria such as those that cause strep throat, pneumonia or urinary tract infections.
– Antiviral medications can help treat certain viral infections, including the coronavirus and influenza. Three antivirals – Paxlovid, remdesivir and molnupiravir – are available by prescription to treat covid in people who are at high risk of serious complications, and four antivirals are approved to treat the flu.
There are also a few other things you can do to help support your body.
– Stay hydrated. Losing water and electrolytes through sweat when you have a fever, as well as through diarrhea and vomiting, can put you at risk for dehydration, so it’s important to drink plenty of water and make sure you’re getting enough electrolytes, Gulick said. Pediatric beverages and sports drinks with added sodium and potassium can help you stay hydrated, and warm liquids such as soups, broths and caffeine-free herbal teas can help ease symptoms such as congestion, body aches and chills, Sood said. Avoid alcohol and caffeinated drinks because they are diuretics and can make dehydration worse.
– Eat, when possible. Listen to your body, but when you have an appetite, eat healthy, whole foods rich in vitamins, minerals and antioxidants such as fresh fruits and vegetables. One strategy is to make smoothies or soups, Bergquist said. Avoid foods high in saturated fats and processed carbohydrates.
– Get rest. Take time to rest as your body does much of its repair work while you sleep, Bergquist said. “Don’t push your body because you want to dedicate that energy to your immune system,” she said.
– Take hot showers or baths. The steam can help break up congestion and clear airways.
– Try zinc. Zinc may help shorten a cold by a day or two. In a 2024 review, researchers found some evidence that zinc might reduce the duration of symptoms by about two days compared with a placebo, though the mineral was associated with mild side effects such as nasal and oral irritation, problems with taste, stomach pain, constipation, diarrhea and vomiting. Most other supplements have no real advantage for colds, including vitamin C, which, when started at the onset of symptoms, doesn’t help lessen the duration or severity, research shows.
– Use honey for a cough or sore throat. Adults and children older than 1 year can add honey to warm tea or water to help soothe sore throats and calm coughs.
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