What to Eat If You Are Positive for an Illness: A Nutritional Guide

December 20, 2025 •

4 min read

According to a 2022 review, eating a healthy, plant-based diet is associated with a lower risk and severity of illnesses like COVID-19. Knowing what to eat if you are positive for an infectious disease is crucial for supporting your body's recovery and boosting your immune system during this critical time.

Quick Summary

A balanced, nutrient-dense diet is essential for recovery after a positive illness diagnosis. Key strategies include prioritizing hydration, consuming immune-supporting vitamins and minerals, and choosing easily digestible foods to manage symptoms like nausea and appetite loss.

Key Points

Stay Hydrated: Drink plenty of water, broth, and herbal teas to prevent dehydration and aid bodily functions, especially if you have a fever.
Eat Immune-Boosting Nutrients: Focus on foods rich in Vitamin C (citrus), Vitamin D (eggs), Zinc (nuts), and Omega-3s (salmon) to support your immune system.
Manage Nausea with Bland Foods: If you have an upset stomach, stick to the BRAT diet (bananas, rice, applesauce, toast) and dry crackers, which are easy to digest.
Reduce Inflammation: Incorporate natural anti-inflammatory foods like ginger, turmeric, and fatty fish to help manage symptoms.
Support Gut Health: Consume probiotic-rich foods such as yogurt and kefir to support a healthy gut microbiome, which is vital for immune function.
Avoid Sugary and Processed Items: Limit foods high in sugar, fat, and salt, as they can hinder recovery and promote inflammation.
Use Smoothies for Nutrient Density: If appetite is low, a nutrient-packed smoothie can be an effective way to get essential calories and vitamins.

Prioritizing Hydration and Electrolyte Balance

When you're sick, fever, sweating, and loss of appetite can lead to dehydration. Proper hydration is arguably the most critical aspect of your nutritional plan during illness, as it supports cellular function and aids in recovery.

Fluid and Electrolyte Sources

Water: The best option for maintaining hydration. Plain, warm, or infused with lemon, it helps flush out toxins and supports bodily processes.
Broths: Chicken, beef, or vegetable broths are soothing, nutrient-rich, and excellent sources of fluid and electrolytes. Their warmth can also help relieve congestion.
Herbal Teas: Ginger, peppermint, and chamomile teas can help soothe a sore throat and calm an upset stomach. Adding honey provides antibacterial properties and can help suppress coughs.
Coconut Water: Naturally rich in electrolytes like potassium, it helps replenish minerals lost through fever and sweating.

When to Consider Electrolyte Drinks

For those experiencing vomiting or diarrhea, replenishing electrolytes is crucial. Low-sugar sports drinks or oral rehydration solutions can be beneficial.

Immune-Supporting Nutrients and Food Sources

To provide your body with the ammunition it needs to fight infection, focus on nutrient-dense, easily digestible foods. The following nutrients are particularly important for a healthy immune response.

Essential Vitamins and Minerals

Vitamin C: A powerful antioxidant that supports immune cells.
- Sources: Citrus fruits (oranges, kiwi), red bell peppers, strawberries, broccoli, and spinach.
Vitamin D: Plays a vital role in regulating the immune system.
- Sources: Egg yolks, fatty fish (salmon), and fortified foods like milk and yogurt.
Zinc: Helps regulate immune function and may reduce symptom severity.
- Sources: Shellfish (oysters, crab), nuts (cashews, almonds), lean meats, and beans.
Selenium: Protects against oxidative stress and may help fight viral infections.
- Sources: Brazil nuts, sunflower seeds, and seafood.

Anti-Inflammatory and Probiotic Foods

Reducing inflammation helps manage symptoms and supports recovery. Probiotics promote a healthy gut microbiome, which is crucial for immune activity.

Ginger and Turmeric: Contain anti-inflammatory compounds that can help ease sore throats and break up congestion.
Yogurt and Kefir: These fermented dairy products contain live active cultures that stimulate the immune system and promote healthy gut bacteria.
Fatty Fish (Salmon): Provides anti-inflammatory omega-3 fatty acids that enhance immune cell function.

Dietary Strategies for Symptom Management

When appetite is low, or you're experiencing nausea, adjusting your diet is key to maintaining nutrition.

Bland and Easily Digested Foods

If your stomach is upset, a bland diet can be easier to tolerate. The BRAT diet (bananas, rice, applesauce, and toast) is a classic choice, as are plain crackers and cereals.

Smoothies for Nutrient Density

Smoothies are an excellent way to pack nutrients into smaller, more manageable portions. Blend fruits, leafy greens, and a protein source like yogurt to support recovery.

Foods with Strong Flavors

If your sense of taste and smell is diminished, incorporating bold flavors can make eating more appealing. Herbs and spices like garlic, onion, and cinnamon can stimulate your senses.

Comparison of Nutrients for Immune Support


Nutrient	Primary Function in Illness	Top Food Sources
Vitamin C	Antioxidant; supports immune cells	Citrus fruits, red bell peppers, broccoli
Vitamin D	Regulates immune response; reduces inflammation	Salmon, eggs, fortified dairy
Zinc	Essential for immune function; reduces severity	Shellfish, nuts, legumes
Omega-3s	Anti-inflammatory; supports immune cells	Salmon, nuts, seeds
Probiotics	Support healthy gut microbiome; boost immunity	Yogurt, kefir, fermented foods

Foods to Limit or Avoid

When you're sick, some foods can hinder recovery by promoting inflammation or being difficult to digest.

Sugary and Processed Foods: High sugar content can suppress the immune system and contribute to inflammation. This includes sugary drinks, candy, and pre-packaged snacks.
Fried and Fatty Foods: Can be hard on the digestive system, especially when experiencing nausea or an upset stomach.
Alcohol: Dehydrates the body and can interfere with the immune system's function.

Conclusion: Fueling Your Recovery

A positive diagnosis for an illness is a cue to prioritize your body's healing process through proper nutrition. While no single food can magically cure an illness, a balanced diet rich in vitamins, minerals, and anti-inflammatory compounds can significantly support your immune system and alleviate symptoms. Prioritizing hydration with water and broths is fundamental, while incorporating nutrient-dense foods like citrus fruits, leafy greens, fatty fish, and probiotics provides the essential building blocks for recovery. Remember to listen to your body and adjust your diet to what you can tolerate, focusing on smaller, more frequent meals if appetite is an issue. Consult with a healthcare provider or a registered dietitian if you have concerns or require specialized nutritional guidance.

For more information on nutrition and immunity, explore Harvard T.H. Chan School of Public Health's resources.

Frequently Asked Questions

Warm broths, herbal teas with honey, and smoothies are excellent choices for a sore throat. Honey has antibacterial properties and can suppress coughs, while warm liquids help soothe the irritation.

Unless advised by a doctor, it is not necessary to avoid all dairy. Probiotic-rich options like yogurt and kefir can support your immune system. However, if you experience diarrhea, some low-fiber diets suggest temporarily limiting dairy products.

If your appetite is low, try eating smaller, more frequent meals. Choose visually appealing foods and experiment with different temperatures, as some people find cold foods more appetizing when sick. Staying lightly active can also help stimulate appetite.

For dehydration, prioritize drinking plenty of water, broths, and herbal teas. If you're experiencing fluid loss from vomiting or diarrhea, electrolyte-rich beverages like coconut water or low-sugar sports drinks can be very helpful.

Yes, spices like ginger and turmeric are known for their anti-inflammatory properties, which can help ease symptoms like congestion and body aches. Adding them to tea or broth can provide both flavor and health benefits.

It is best to limit sugary drinks, highly processed foods, and fatty or fried foods. These can increase inflammation, suppress immune function, and be difficult for your body to digest when it's already under stress.

Probiotics, found in foods like yogurt, kefir, and kimchi, introduce beneficial bacteria to your gut. A healthy gut microbiome is a key component of a robust immune system, helping your body fight off infections.