Should you really ‘feed a cold, starve a fever’ when sick?


If you grew up under any sort of adult supervision, there’s a good chance you’ve heard this gem once or twice: “Feed a cold, starve a fever.” Most likely, no one ever explained where the theory came from, or why it would work. As you grew older, chances are high that you questioned this little piece of advice—with good reason. But you might be surprised to learn, there’s at least a piece of truth behind it. Feeding colds, and starving fevers, both might be beneficial for your health.

To be clear, there’s more chance at play here than anything else. The origins of “Feed a cold, starve a fever” comes from the Middle Ages, when “doctors” believed that sickness came in two forms—hot and cold.

The reason that colds are called colds in the first place is because they were considered an example of sickness stemming from low energy, and low temperature. You were, quite literally, cold.

So you were encouraged to eat, as a way to add fuel and stoke the furnace of your body.

On the flip side, fevers were a sign that your body was running too hot—that, just like an overheated oven, you had too much fuel and were burning through it too quickly. So you starved a fever in order to reduce the fuel, and bring down your temperature.

You don’t need me to tell you that’s gobbledygook. In fact, it’s important to remember that fevers are actually good things. They are your body’s defense response to invasion. If a nasty enough bug invades, you heat up your body—their world—so that the invaders become uncomfortable and, hopefully, die.

Sort of like turning the thermostat up to 90 degrees, in order to get rid of unwanted guests. Make them sweat enough, and they’ll head for the door.

Fevers protect you, and aren’t directly anything to fear. A very high fever can be dangerous, but as long as you stay below about 102 degrees, you aren’t in any danger. Indeed, bringing down a low fever just weakens your defense system.

However, even though the ancients didn’t understand any of that—and even though they completely misunderstood the mechanisms behind illness—they did stumble upon at least a grain of truth.

It turns out, in many cases, you actually do want to eat when you have a cold. And you want to avoid food when you have a fever.

Well, sort of.

Feed A Virus

A recent study done in mice uncovered some very unexpected results.

Specifically, mice that were suffering from a viral infection saw their metabolic rates shoot up. Their cells were working overtime, trying to get rid of the invader.

And, when those mice received an infusion of nutrition in their diets, they did better.

The key turns out to be glucose levels. They fought off the virus faster than mice without the extra sugar, and recovered their health faster as well.

In other words, viral infections—like colds, or the flu—actually react better to extra food. Especially sugar—the easily accessible fuel of cells.

Now, this isn’t an excuse to order a hot fudge sundae whenever you get a sniffle. It’s easy to overdo it.

Instead, just make sure you keep eating. Add a teaspoon or two of honey to your tea. And, if you’ve a hankering for any fiber-rich foods that are full of sugar—like fruit—now’s the time to load up.

Because, to put it plainly, your cells are burning through more than their average share of sugar while you’re sick. And replenishing your stores quickly will aid your immune system in its fight.

Starve Bacteria

On the other hand, mice that had bacterial infections of listeria saw very different results.

Remember—bacterial infections are much more likely to cause fevers than viruses. It isn’t a hard-and-fast rule—bad cases of the flu come with fevers—but generally speaking, a fever is often caused by bacteria.

And when nutrition was added to the diet of mice with bacterial infections, they didn’t get better faster. In fact, they all died.

This isn’t because the bacteria thrived, or that the sugar hurt the immune systems in mice.

Rather, it was because the increase in glucose changed the metabolism in the sick mice. And that change in metabolism turned out to make for more fertile ground for the bacterial infection.

So feeding a fever turned out to be deadly—at least for these mice infected with bacteria.

So there’s some truth to the old wives’ tale after all. Perhaps that’s why it’s stuck around, long after the reason for its genesis has been thoroughly discredited.

The Best Medicine

Feeding a viral infection—like a cold—and starving a bacterial infection—often accompanied by fever—may turn out to be great advice.

It also may not. There haven’t been enough studies done, and what works in mice might not hold true in humans.

But it’s a safe motto to stick to. Just don’t rely on it alone.

There are much better ways to get rid of invaders—naturally, without worrying about your food intake.

If you’re dealing with a virus, eucalyptus and tea tree oil can help open up your nasal passages—especially if you inhale them as steam. Cinnamon and ginger help with congestion, by reducing inflammation and allowing phlegm to flow. Mullein—a biannual herb that grows in temperate regions—thins and loosens phlegm and mucus. Apple cider vinegar helps to soothe sore throats, and in many cases goes to work directly attacking the bug.

For bacterial infections, aloe vera has wonderful antibacterial properties. Turmeric—found in cumin—also is very antibacterial, as well as being a great anti-inflammatory. Probiotics—like those found in plain, natural yogurt, or in supplements—can crowd out damaging bacteria in your gut. Newport Natural Health, for example, offers a probiotic formula made up of six unique strains of beneficial bacteria, each conferring its own benefit to the gut, the immune system and the body as a whole. Plus, it’s microencapsulated to ensure all 10 billion CFUs (colony forming units) can survive your powerful stomach acids and arrive safely in the intestines, where they do their most important work—learn more about this top-notch probiotic here.  And again, apple cider vinegar is both antibacterial and a great anti-inflammatory.

Of course, if you have a bad bacterial infection, antibiotics are a last resort for getting everything under control. But in many cases, you can take care of minor infections on your own.

Whenever it’s an option, I prefer the natural route.

And, now I know that I can recommend that our readers remember the advice of their mothers, and grandmothers. You really should feed that cold (virus), and starve that (bacterial) fever.


Last Updated: December 21, 2019
Originally Published: October 24, 2016