Warm broth, honey, ginger, and zinc-rich foods consistently show up in the research as genuinely helpful during common illnesses, though the reasons vary depending on whether you are fighting a respiratory infection, a stomach bug, or a fever. Your body burns significantly more calories when battling infection, so eating even small amounts of the right foods gives your immune system the raw materials it needs. The best choices depend on what symptoms you are dealing with, and a few widely believed rules about eating while sick turn out to be wrong.
Why Your Body Needs More Fuel During Illness
Fever is expensive, metabolically speaking. Your resting energy expenditure climbs roughly seven percent for every degree Celsius of fever, and during acute infections that spike can push total energy use about 30 percent above normal.1Pediatric Research. Effect of Malaria and Fever on Energy Metabolism in Gambian Children That increase comes largely from the immune system ramping up white blood cell production, manufacturing antibodies, and generating heat to make conditions less hospitable for pathogens.2PubMed. The metabolic cost of fever At the same time, infection triggers the release of cytokines that suppress appetite, a phenomenon called sickness-associated anorexia.3PubMed Central. Sickness-Associated Anorexia: Mother Nature’s Idea of Immunonutrition? So your body simultaneously demands more energy and makes you less inclined to eat.
That loss of appetite is not random. Researchers consider it an evolved response found across vertebrates and even invertebrates, designed to redirect energy away from digestion and toward immune defense.4Integrative and Comparative Biology. Vertebrate sickness behaviors: Adaptive and integrated neuroendocrine immune responses The practical takeaway is that you should not force yourself to eat large meals. But eating nothing at all during a multi-day illness puts you at a disadvantage, because the body starts breaking down its own muscle protein to fuel the immune response.5PubMed. The requirements of protein & amino acid during acute & chronic infections Small, nutrient-dense meals or snacks throughout the day strike the best balance between honoring your reduced appetite and keeping the immune system supplied.
Chicken Soup Earns Its Reputation
Chicken soup has been a go-to remedy for centuries, and the science behind it is more interesting than a simple placebo effect. The warm liquid helps keep you hydrated, and the steam may temporarily open congested airways. But there appears to be more going on at the cellular level. In an animal study using immunosuppressed mice, chicken soup promoted the recovery of blood markers, stimulated cytokine secretion, and increased immunoglobulin levels compared to controls.6PubMed Central. Immunomodulatory effects of chicken soups prepared with the native cage-free chickens and the commercial caged broilers Mouse research does not translate directly to humans, but these results align with earlier work suggesting chicken soup has mild anti-inflammatory properties that may ease upper respiratory symptoms.
A practical advantage of soup is that it delivers fluid, electrolytes from the salt, protein from the chicken, and easily digested carbohydrates from any noodles or rice all in one bowl. When your appetite is small, foods that pack multiple nutritional needs into a single serving are especially valuable. Homemade versions with vegetables add micronutrients, but even a store-bought can of chicken soup covers the basics if you cannot manage cooking.
Honey for Coughs and Sore Throats
If a persistent cough is keeping you up at night, honey is one of the best-supported remedies available. A systematic review and meta-analysis found that honey outperformed usual care for cough frequency, cough severity, and overall symptom scores in upper respiratory infections.7BMJ Evidence-Based Medicine. Effectiveness of honey for symptomatic relief in upper respiratory tract infections: a systematic review and meta-analysis The reviewers noted honey provides a cheap, widely available alternative to antibiotics, which do nothing for viral infections anyway. In children specifically, a randomized placebo-controlled trial showed that a single bedtime dose of honey improved nocturnal cough and sleep quality more than a date-extract placebo, regardless of honey variety.8Pediatrics. Effect of Honey on Nocturnal Cough and Sleep Quality: A Double-blind, Randomized, Placebo-Controlled Study
A spoonful of honey stirred into warm tea or water is the simplest delivery method. The coating effect on the throat likely soothes irritation, and honey has mild antimicrobial properties of its own. One important caveat: honey should never be given to children under one year old due to the risk of infant botulism. For everyone else, it is a safe, effective, and pleasant-tasting option that belongs in your sick-day toolkit.
Ginger for Nausea and Stomach Trouble
When illness hits your gut rather than your chest, ginger is the standout food. A systematic review of clinical trials found that about 1,500 milligrams of ginger per day, split into smaller doses, was beneficial for relieving nausea.9PubMed Central. Ginger in gastrointestinal disorders: A systematic review of clinical trials Part of the mechanism involves ginger speeding up gastric emptying. In a controlled study of healthy volunteers, ginger roughly halved the time it took the stomach to move food along, compared to a placebo.10PubMed. Effects of ginger on gastric emptying and motility in healthy humans That faster transit means less time for food to sit and trigger the queasy feeling.
You do not need much to get the effect. Grating a thumb-sized piece of fresh ginger into hot water makes a tea that settles the stomach within about 20 minutes. Ginger chews, ginger ale made with real ginger (check the label, as many brands use artificial flavoring), and even pickled ginger slices all count. For someone dealing with a stomach virus, pairing small sips of ginger tea with plain crackers or rice can help you keep something down when nothing else appeals.
Probiotics for Stomach Bugs
If a stomach virus is causing diarrhea, probiotic-rich foods or supplements may shorten its duration. In a study of children with acute rotavirus gastroenteritis, certain probiotic strains shortened the duration of diarrhea by roughly a day compared to placebo, with no adverse effects.11PubMed. Probiotic bacteria, B. longum and L. acidophilus inhibit infection by rotavirus in vitro and decrease the duration of diarrhea in pediatric patients A day might not sound dramatic, but when you are dealing with the misery of a stomach bug, any reduction counts.
Yogurt with live active cultures is the most accessible probiotic food. Kefir, miso soup, and fermented vegetables like sauerkraut are other options, though during active vomiting you may want to wait until you can tolerate bland foods before adding fermented products. The goal is replenishing your gut’s beneficial bacteria, which get disrupted both by the infection itself and by any medications you may be taking.
Zinc Lozenges and the Common Cold
Zinc stands apart from most “immune-boosting” nutrients because the evidence behind it is specific and relatively strong. A meta-analysis of seven trials estimated that zinc lozenges reduced common cold duration by about a third, with zinc acetate showing roughly a 40 percent reduction and zinc gluconate about 28 percent, a difference that was not statistically significant between the two forms.12PubMed Central. Zinc lozenges and the common cold: a meta-analysis comparing zinc acetate and zinc gluconate, and the role of zinc dosage In one placebo-controlled trial, mean cold duration in the zinc group was about four and a half days versus eight days in the placebo group, with cough duration cut roughly in half.13PubMed. Duration of symptoms and plasma cytokine levels in patients with the common cold treated with zinc acetate
The catch is that zinc works best when started within the first 24 hours of symptoms. Waiting until day three of a cold and then sucking on zinc lozenges likely will not do much. Another caveat: these studies used supplemental zinc lozenges, not zinc from food. While oysters, red meat, pumpkin seeds, and chickpeas are all good dietary sources of zinc, eating them during a cold is unlikely to deliver the concentrated dose that produced those trial results. Zinc lozenges are cheap and widely available at pharmacies, and they are the form that matches the clinical evidence. A separate systematic review that also included zinc lozenges found cold duration dropped by about two days, though the researchers rated the overall certainty of the evidence as low due to inconsistency across studies.14PubMed Central. Zinc Supplementation Reduces Common Cold Duration among Healthy Adults: A Systematic Review of Randomized Controlled Trials with Micronutrients Supplementation Still, the direction of the findings is consistent: zinc lozenges shorten colds. Just start them early.
What About Vitamin C and Garlic
Vitamin C is probably the most famous cold remedy of all, but the evidence is more modest than the reputation. A Cochrane review of 30 trials found that taking vitamin C daily as a preventive measure did not reliably reduce the number of colds people caught. There was a consistent but small reduction in how long colds lasted, and some evidence that a large single loading dose at the onset of symptoms might help more than lower daily doses.15Cochrane Database of Systematic Reviews. Vitamin C for preventing and treating the common cold In practical terms, eating citrus fruits, bell peppers, and berries when you are sick is not going to hurt, and the vitamin C they provide contributes to normal immune function. But the massive effect that many people expect from vitamin C simply has not materialized in the data.
Garlic has a long folk history as an infection fighter. A Cochrane review on garlic and the common cold found the available evidence insufficient to draw strong conclusions.16PubMed Central. Garlic for the common cold One randomized trial of aged garlic extract supplementation found that while the supplement did not significantly reduce the overall incidence of colds and flu, those who took it reported fewer symptoms, about 60 percent fewer days of impaired function, and roughly 60 percent fewer missed work or school days.17PubMed. Supplementation with aged garlic extract improves both NK and γδ-T cell function and reduces the severity of cold and flu symptoms: a randomized, double-blind, placebo-controlled nutrition intervention That is promising but comes from a single trial using a specific commercial supplement, not raw garlic cloves. Adding garlic to your chicken soup is unlikely to cause any harm, and the flavor alone might make eating more appealing when nothing tastes good, but the evidence does not yet support garlic as a standalone cold treatment.
Hydration Matters More Than Any Single Food
Across all types of illness, staying hydrated is more important than any particular food choice. Fever increases fluid loss through sweating, respiratory infections cause fluid loss through mucus production, and vomiting or diarrhea can dehydrate you rapidly. Water is always a solid baseline, but it does not replace the electrolytes you lose when sick. Broth, diluted fruit juice, and oral rehydration solutions do a better job of maintaining your sodium and potassium levels.
If you are dealing with significant vomiting or diarrhea, especially in children, the choice of rehydration fluid matters. Standard oral rehydration solutions are specifically formulated with the right balance of sugar and salt to maximize absorption. Common household drinks like fruit juice, sports drinks, and soda have higher sugar content and lower sodium than what the body needs, and in children with gastroenteritis they can actually worsen diarrhea by pulling more water into the gut.18PubMed Central. Understanding the use of oral rehydration therapy: A narrative review from clinical practice to main recommendations For mild illness in adults, this distinction is less critical. Herbal tea, warm water with lemon and honey, diluted juice, and clear broths all work fine. The key is sipping consistently rather than trying to drink a lot at once, which can trigger nausea in an already unsettled stomach.
Spicy Foods and Congestion
If you have ever eaten something spicy and felt your nose start running, you have experienced the decongestant effect of capsaicin firsthand. Capsaicin, the compound that gives chili peppers their heat, works on specific receptors in the nerve fibers of your nasal passages.19PubMed Central. Capsaicin for non‐allergic rhinitis That initial burst of runny nose can temporarily thin and clear congestion. A bowl of spicy broth or a curry with chili flakes can make breathing easier for a while, though the effect is short-lived.
The downside is that spicy food can irritate an already sore throat and may worsen acid reflux, which tends to flare up when you are lying in bed all day. If your illness involves nausea, spicy foods are a bad idea. But for someone dealing mostly with sinus congestion and a stuffy nose, a little heat in the soup is a reasonable strategy.
The Milk and Mucus Myth
One of the most persistent beliefs about eating while sick is that dairy products increase mucus production and make congestion worse. The research says otherwise. In a study where healthy adults were deliberately infected with a cold virus, those who drank milk did not produce any more nasal secretions than those who avoided it.20PubMed. Relationship between milk intake and mucus production in adult volunteers challenged with rhinovirus-2 People who already believed the myth reported feeling more congested after drinking milk, but objective measurements showed no difference. Separate Australian research confirmed that soy-based drinks with similar thickness produced the same perceived coating sensation in the mouth and throat, suggesting the feeling is about texture, not any biological effect of dairy.21PubMed. Milk consumption does not lead to mucus production or occurrence of asthma
This matters because dairy can be one of the easiest ways to get calories and protein into a sick person who has no appetite. Yogurt is soft, cold on a sore throat, and delivers probiotics. A glass of milk provides protein, fat, and fluid. Avoiding these foods based on the mucus myth means cutting out some of the most nutritionally convenient options for no real benefit.
Does “Feed a Cold, Starve a Fever” Hold Up
This old saying has a grain of biological truth, but following it literally is a bad idea. A small study of human volunteers found that eating stimulated the branch of the immune system geared toward fighting viruses, while fasting stimulated a branch more oriented toward bacterial defense.22PubMed Central. Feed a cold, starve a fever? Some researchers have hypothesized that this could mean eating during a viral cold and fasting during a bacterial fever each push the immune system in the right direction.23PubMed. “Starve a fever and feed a cold”: feeding and anorexia may be adaptive behavioral modulators of autonomic and T helper balance
The problem is that this hypothesis has not been tested in any meaningful clinical way. You usually cannot tell whether your illness is viral or bacterial without a lab test, fevers accompany both types, and deliberately starving yourself during any acute illness risks dehydration and muscle wasting. As discussed earlier, infection already drives appetite down through sickness-associated anorexia. The body’s own appetite signals are a better guide than any folk proverb. Eat when you can, choose foods that are easy to tolerate, and do not force large meals if your body is not asking for them.
Protein and Rebuilding After the Worst Passes
Once the acute phase of illness passes and your appetite starts returning, your body has repair work to do. Infections create a negative nitrogen balance, meaning the body breaks down more protein than it builds, and the longer the illness lasts the more muscle mass you can lose.5PubMed. The requirements of protein & amino acid during acute & chronic infections This is especially relevant for older adults, who lose muscle more easily and regain it more slowly. During recovery, protein-rich foods like eggs, Greek yogurt, lentils, fish, and lean meats help replenish what was lost.
Recovery eating does not need to be aggressive. Your digestive system has been running on minimal input and may not handle rich or heavy foods right away. Scrambled eggs, a bowl of lentil soup, or a smoothie made with yogurt and banana are gentle ways to increase protein intake without overwhelming a sensitive stomach. The transition from “sick food” to normal eating can take a few days, and that is fine. The goal is a gradual ramp-up in both quantity and variety as your appetite rebuilds.
Foods That Are Worth Avoiding
While the emphasis should be on what helps rather than rigid restrictions, a few categories of food tend to make symptoms worse. Alcohol dehydrates you and suppresses immune function, making it the single clearest thing to skip. Very sugary foods and drinks can contribute to inflammation and, as noted in the hydration section, may worsen diarrhea in children by increasing osmotic load in the gut. Fried and heavily processed foods are simply hard to digest when your system is already under stress, and they provide few of the nutrients your immune system actually needs.
Caffeinated drinks are a gray area. Coffee and tea provide fluid and the warmth can feel soothing, but high caffeine intake is mildly diuretic and can interfere with the rest your body badly needs. A cup or two is unlikely to cause problems, but relying on coffee to push through illness instead of sleeping is counterproductive. The best approach is to let your body rest, keep sipping fluids, and save the energy-dense or stimulating foods for when you feel genuinely hungry again.