- The old saying is not backed by science, and modern research disagrees.
- When sick, your body needs steady nourishment and fluids, not extra or restricted food.
- Eating small meals, staying hydrated and choosing simple foods can support immune system.
For as long as we’ve been catching colds and coming down with fevers, the old adage, “feed a cold, starve a fever” has been passed from one generation to the next. It sounds clever, but many people still wonder whether there’s any actual science behind the advice. Do you really need to eat more when you have a cold? And should you dramatically cut calories when you’re running a fever? What are you supposed to do if you simultaneously have a cold and a fever?
If you’ve ever had the flu, for example, you know firsthand that appetite rarely follows rules. Even if you’re a steak lover, protein foods are usually the last thing you’d reach for when you’re queasy or flat-out exhausted. It’s often comforting carbs like toast, crackers, cereal or whatever goes down easiest that feel most appealing, if any food appeals at all.
“Long before scientists understood the immune system, people likely noticed this pattern and turned it into a catchy rule of thumb,” says Liz Weiss, RDN. Weiss tells us, “What we know now is that changes in appetite are part of the body’s normal response to illness, sometimes referred to as sickness behavior, rather than a signal that we should intentionally eat more or less.” Weiss concurs that the saying has likely stuck because it feels intuitive, not because it’s been proven true.
Here’s what modern nutrition experts and medical research say about this long-standing myth.
Should You “Feed a Cold”?
Short answer: Not exactly.
The original idea dates back centuries when people believed that colds were caused by low body temperature needing warmth (by eating food) and fevers by high temperatures needing cooling (achieved by fasting). We now know colds don’t lower body temperature. We also know that staying nourished supports the immune system in both circumstances.
When you have a cold, you may still have an appetite, and you might even have cravings for warm, soothing foods. That’s not surprising, as Weiss points out, “Warm liquids can temporarily ease symptoms like sore throat, runny nose and cough, which may make it easier to eat and drink when you’re sick.” Warm liquids also help ease congestion while simultaneously keeping you hydrated. Hydration is especially key because mucus tends to thicken when you’re dehydrated, making symptoms feel worse. Taking a hot shower may loosen mucus as well.
Research even shows that chicken soup may have properties that gently reduce inflammation in the upper respiratory tract and support mucus clearance.
Basically, you don’t need to “feed” a cold with extra calories, but consistent nourishment helps keep your immune defenses strong and will help you recover from your weakened condition. Think small, regular meals with protein, produce and fluids.
Should You “Starve a Fever”?
Absolutely not.
When you have a fever, your body is working hard. Fever raises your metabolic rate, meaning you burn more energy than usual while your immune system fights the infection. Intentionally restricting food can actually work against your body, since limiting nutrients may make it harder for your immune system to do the work it needs to fight what’s ailing you.
Even though your body needs more energy when you’re sick, it’s completely normal to have little or no appetite. Illness can change the way food tastes, cause nausea or fatigue and trigger the release of cytokines—chemical messengers that help your immune system fight infection. While cytokines are doing important work behind the scenes, they also tend to dial down hunger, which is why eating can feel unappealing when you’re not feeling well.
However, as Jane Leverich, RDN, highlights, “Though the lack of appetite with a fever is a normal physiological response, it doesn’t mean that the body doesn’t need nourishment to heal.” Leverich went on to say, “Fluids, electrolytes and small, easily-digested foods support recovery, even when hunger cues are lessened.” Sharon Hochweiss, M.D., highlighted, “Hydration is critical during a fever to replace insensible losses from the skin as the body will sweat in an attempt to cool itself off.” Fever dehydrates your system. Therefore, Leverich agrees, “During a fever when appetite is low, addressing hydration should be the priority,” followed by gentle nourishment in whatever form feels tolerable. Some foods to try include:
- Easy-to-digest foods, like oatmeal, yogurt, toast, hot cereal, fruit, tea or broth
- Nutrient-dense liquids, such as smoothies or pureed soups, when solids aren’t appealing
- Electrolyte-rich fluids, especially if sweating or dehydration is a concern
Restricting food may only be appropriate, as Dr. Hochweiss pointed out, “In situations where the intestines themselves are the structure affected by the disease process, where movement within the digestive tract would cause harm or worsen a condition there.” She went on to say, “This might be if there was a blockage in the intestine or inflammation there due to diverticulitis or colitis and the treatment for those conditions involves keeping the bowel at rest so solid foods are contraindicated.”
Ultimately, if you can’t keep fluids down, or if a fever lasts more than a few days, that’s the time to call a healthcare provider.
Other Tips for Supporting Your Immune Health
Even though the old adage isn’t scientifically sound, there are some simple, age-old habits that help support the body during illness.
- Stay hydrated. Fluids help manage fever-related fluid losses and keep mucus thin, which can ease congestion. Warm liquids, like tea with honey and lemon, may also help soothe the throat.
- Include protein at meals and snacks. Protein helps repair tissues and fuels the production of immune cells. Eggs, yogurt, tofu, cheese and beans are easy options.
- Choose produce rich in vitamins and antioxidants. Vitamin C–containing foods like citrus, berries, peppers and kiwi support overall immune function.
- Prioritize rest. Sleep is one of your most powerful tools for recovery. Even short bouts of rest throughout the day help the immune system work more efficiently.
- Eat smaller, more frequent meals if your appetite is low. This helps you meet nutritional needs without overwhelming your system during fever or fatigue.
- Supplementation. The current evidence of efficacy for supplementation of zinc, vitamins D and C, and Echinacea is debatable. While they may help some people who have a common cold, further studies are needed on this topic. “There is little evidence that vitamin C or echinacea does more than nominally improve cold symptoms but studies do show that zinc, if used directly where the pathology is manifesting, can reduce the duration of cold symptoms by over 40%,” Dr. Hochweiss says. “That means using zinc lozenges for a sore throat or zinc nasal swabs for a head cold can be helpful, as the zinc reduces the transfer of cold viruses from one cell to another, shortening the lifespan of the virus in the body.”
- Avoid alcohol and caffeine. When you’re feeling ill, you might feel like having toast, but not ‘toast-ing’ with alcoholic beverages. Dr. Hochweiss cautions us, “It’s best to avoid caffeine and alcohol as these can work counter to the desired effect, acting as diuretics instead of overall replenishing the body’s fluids.” Both caffeine and alcohol can also disrupt sleep when rest is essential.
- Limit inflammatory foods. Weiss points out, “[High-sugar] drinks may crowd out more nourishing fluids while greasy, spicy or highly acidic foods can aggravate nausea, reflux or sore throats for some people.”
Our Expert Take
The classic saying “feed a cold, starve a fever” may be a long-standing saying, but it doesn’t reflect what your body actually needs when you’re sick, nor is it supported by modern-day science. Your appetite may naturally shift. Colds might welcome warm meals, while fevers can make food seem unappealing—but your immune system needs energy and hydration either way. Instead of trying to eat more or less based on an outdated adage, support yourself with:
Most importantly, listen to your body. Give it gentle nutrition when you can, hydrating fluids if eating is tough and medical care when symptoms worsen or don’t improve. Getting well is less about following a catchy phrase and more about giving your body the steady support it needs to recover.
