When you have the flu, your body needs fluids, easy-to-digest calories, and enough protein to keep your immune system running. The best foods are ones that deliver nutrients without making nausea or congestion worse: broth-based soups, eggs, cooked vegetables, whole fruits, and plenty of liquids. What matters most is eating something, even in small amounts, rather than following a rigid plan.
Why Chicken Soup Actually Works
Chicken soup isn’t just comfort food. Researchers at the University of Nebraska Medical Center tested a traditional chicken soup recipe in the lab and found it significantly slowed the movement of white blood cells called neutrophils. That matters because neutrophils rushing to your airways are part of what causes the congestion, swelling, and misery of a respiratory infection. By calming that response, chicken soup has a mild anti-inflammatory effect that can ease symptoms in your nose and throat.
The study found something else interesting: the effect wasn’t limited to one ingredient. The chicken, carrots, onions, celery, and other vegetables each had some inhibitory activity on their own. The benefit came from a liquid, non-particulate component of the broth, meaning you don’t need to eat every chunk of vegetable to get the effect. Even sipping the broth alone helps, which is useful when solid food feels like too much.
Protein Helps Your Immune System Fight Back
Your body burns through protein faster when you’re fighting an infection. Immune cells, antibodies, and the repair signals your tissues use to recover all require amino acids. Research from the Institute of Food Technologists confirms that protein deficiency weakens immune function by reducing antibody production and depleting the immune tissue in your gut. Low protein intake also increases susceptibility to viral infections like influenza specifically.
At the same time, the inflammatory response from a virus accelerates muscle breakdown. Eating enough protein helps counteract that, preserving muscle mass and supporting recovery. You don’t need to force down a steak. Good options when you’re sick include:
- Scrambled eggs: soft, bland, and easy to eat in small amounts
- Skinless chicken or turkey: especially shredded in soup or broth
- Greek yogurt: if your stomach tolerates dairy, it delivers protein plus beneficial bacteria
- Beans or lentils in soup: a good plant-based option that’s gentle on the stomach
The BRAT Diet Is Outdated
If you’re dealing with nausea or stomach symptoms alongside the flu, you may have heard that bananas, rice, applesauce, and toast (the BRAT diet) are the way to go. That advice is outdated. The American Academy of Pediatrics no longer recommends a strict BRAT diet for children, and Cleveland Clinic advises adults to follow it for no more than a day or two at most. The problem is that it lacks calcium, vitamin B12, protein, and fiber, all things your body needs to recover. Following it for longer than 24 hours can actually slow healing.
A better approach: eat bland, soft foods when your stomach is at its worst, then expand to more nutritious options as soon as you can tolerate them. Scrambled eggs, cooked vegetables, and skinless poultry are all considered next-step foods once your appetite starts returning. Smaller, more frequent meals tend to sit better than three large ones.
Ginger for Nausea
If nausea is keeping you from eating, ginger is one of the best-studied natural remedies. It works by speeding up the movement of food through your digestive tract and by acting on receptors in both your gut and brain that trigger the urge to vomit. Clinical trials have used doses ranging from 250 milligrams to 2 grams per day, split across three or four servings, and found that 1 gram per day was just as effective as 2 grams.
In practical terms, that’s about a teaspoon of freshly grated ginger steeped in hot water as tea, or a few pieces of crystallized ginger throughout the day. Ginger ale from the store typically contains very little real ginger, so it’s not a reliable source. Fresh ginger tea or ginger chews are better bets.
Fluids Matter More Than Food
Fever, sweating, and breathing through your mouth all pull water out of your body faster than usual. Staying hydrated thins mucus, prevents headaches, and keeps your kidneys working properly while they filter out the metabolic waste of fighting an infection. Water is fine, but fluids with some electrolytes and calories are better when you’re not eating much. Broth, diluted fruit juice, herbal tea with honey, and oral rehydration drinks all count.
Caffeine and alcohol both work against you. Caffeine is a mild diuretic, and alcohol suppresses immune function and dehydrates you further. Skip both until you’re feeling better.
Zinc and Vitamin C: What the Evidence Shows
Zinc can shorten a cold when taken within the first 24 hours of symptoms, but the evidence is specifically for high-dose zinc lozenges delivering more than 75 milligrams per day. That’s a supplement-level dose, not something you’d realistically get from food alone during a day when you’re barely eating. Still, zinc-rich foods like eggs, poultry, beans, and pumpkin seeds contribute to your overall immune function and are worth including when you can.
Vitamin C tells a similar story. Regular supplementation modestly reduces cold duration, by about 8% in adults and 14% in children. But taking vitamin C after symptoms have already started shows no clear benefit. Eating vitamin C-rich foods like oranges, strawberries, bell peppers, and kiwi is good general practice, but don’t expect a glass of orange juice to cut your flu short once you’re already sick.
Yogurt and Fermented Foods
Your gut plays a larger role in immune defense than most people realize, and the flu can disrupt the balance of bacteria living there. A pooled analysis of 10 randomized controlled trials covering over 3,400 participants found that people who consumed probiotics from yogurt or supplements developed 12% fewer upper respiratory infections than those who didn’t. They were also less likely to need antibiotics. The caveat: probiotics didn’t significantly shorten the duration of infections that did occur, and some animal studies testing specific strains against influenza have come up empty.
If you enjoy yogurt, kefir, or other fermented foods and your stomach handles them well, they’re a reasonable addition. Look for products with live active cultures. But don’t rely on them as a treatment for the flu you already have.
What to Avoid
You may have heard that dairy increases mucus production. The evidence doesn’t support this. Studies have found no measurable increase in mucus output from milk or cheese. Some people feel a coating sensation in their throat after drinking milk, which can be unpleasant when you’re already congested, so skip it if it bothers you. But there’s no biological reason to eliminate dairy across the board.
Foods worth avoiding are the ones that genuinely make symptoms worse or slow recovery: alcohol, heavy caffeine intake, very greasy or fried foods that can aggravate nausea, and anything excessively sugary on an empty stomach. Beyond that, eat whatever appeals to you and sits well. Your appetite is a reasonable guide. The single most important thing is to keep getting fluids and some calories in, even if meals are small and simple.