Should I eat more or less food during an infection? Nutrition Diet Explained

October 12, 2025 •

4 min read

While the ancient maxim "feed a cold, starve a fever" persists, medical experts confirm it's largely fiction. The truth about if you should eat more or less food during an infection is more nuanced: your body actually requires more calories and nutrients to fuel the immune system, but your appetite may naturally decrease.

Quick Summary

During an infection, the body's energy needs increase to fuel the immune response, but appetite often wanes due to inflammatory chemicals. Focus on staying hydrated and consuming small, nutrient-dense meals based on your hunger cues, rather than overeating or fasting. Key nutrients like protein, vitamins, and minerals are critical for a speedy recovery.

Key Points

Immune Response Increases Calorie Needs: Your metabolism speeds up during an infection, especially with a fever, so your body requires more energy and nutrients to fight the illness effectively.
Appetite Loss is Normal: Cytokines released by the immune system can suppress appetite, so it's natural to not feel as hungry. Do not force yourself to eat if it causes discomfort.
Hydration is Key: Staying well-hydrated is paramount, as fluids help with fever, thin mucus, and replace lost electrolytes from vomiting or diarrhea.
Focus on Nutrient Density: When you do eat, choose small, frequent meals or liquid nourishment packed with vitamins, minerals, and protein to give your body the building blocks for recovery.
Avoid Certain Foods: Limit greasy, sugary, or spicy foods, as they can be hard on your digestive system and hinder the immune response.
Listen to Your Body: The best approach is a balanced one—prioritize fluids, eat according to your hunger, and provide nutrient-rich, easily digestible foods.
Consult a Professional for Concerns: If appetite loss is prolonged or symptoms worsen, seek medical advice.

Your Body's Increased Energy Needs When Ill

When fighting an infection, your body's immune system enters a state of heightened activity, which requires a significant amount of energy. Studies show that a fever alone can increase your metabolic rate, causing you to burn more calories. This increased energy demand is necessary to produce immune cells, antibodies, and other proteins to fight off pathogens. However, this is in direct opposition to a common symptom of illness: a suppressed appetite.

The Role of Cytokines and Appetite Suppression

Your body's immune response releases chemical messengers called cytokines. While these are crucial for fighting infection, they also act on the hypothalamus in the brain, which regulates appetite. This can cause you to feel less hungry or even nauseated. This loss of appetite is an evolutionary response to conserve energy that would otherwise be spent on digestion, allowing the body to focus its resources on healing.

Separating Fact from Fiction: 'Feed a Cold, Starve a Fever'

The old wives' tale "feed a cold, starve a fever" is outdated advice. Regardless of whether you have a cold, flu, or fever, your body needs nutritional support to recover. Fasting during a fever can deprive your immune system of the necessary fuel and building blocks it needs, potentially slowing down recovery and leading to muscle tissue breakdown. The proper approach is to listen to your body and provide it with easy-to-digest, nutrient-rich foods whenever you feel hungry.

The Cornerstone of Recovery: Prioritizing Hydration

More important than the debate over eating more or less is the undisputed fact that staying well-hydrated is crucial during an infection.

Fever: Fluids are lost through sweat during a fever as the body tries to regulate its temperature. Replenishing these fluids is vital to prevent dehydration.
Mucus: Proper hydration helps to thin mucus, making it easier to clear from your airways, which is especially helpful for respiratory infections like colds or the flu.
Replenishing Electrolytes: Vomiting and diarrhea can lead to significant fluid and electrolyte loss. Broths, soups, and drinks with added electrolytes can help restore balance.

Navigating a Reduced Appetite

When your appetite is low, forcing yourself to eat a full meal can be counterproductive and uncomfortable. The goal is to provide consistent, small amounts of energy and nutrients throughout the day. Here are some strategies:

Focus on small, frequent meals. Instead of three large meals, aim for five or six smaller, nutrient-packed 'snacks' every few hours.
Try nourishing liquids. If solid food is unappealing, liquid nutrition options like broths, smoothies, or protein shakes can provide calories and hydration in one go.
Eat easy-to-digest foods. Bland options are often best. The BRAT diet (bananas, rice, applesauce, toast) is a classic example for stomach troubles.

Nutrient-Rich Foods to Support Your Immune System

To maximize your intake when appetite is low, prioritize these foods:

Soups and Broths: Warm liquids help clear congestion and are a great source of fluids and electrolytes. Chicken soup also provides protein and anti-inflammatory benefits.
Ginger: Known for its anti-nausea effects, ginger tea or ginger ale (with real ginger) can help soothe an upset stomach.
Yogurt and Fermented Foods: Probiotics found in yogurt, kefir, and sauerkraut can support gut health, which is a major part of the immune system.
Fruits and Vegetables: High in vitamins, minerals, and antioxidants, fruits like oranges, strawberries, and leafy greens support immune function and help repair cells.
Lean Protein: Protein is essential for producing antibodies and immune cells. Easy-to-eat options include eggs, diced chicken in soup, and beans.

Foods and Drinks to Limit

Certain items can hinder your recovery and cause digestive upset:

Sugary Foods: Excess sugar can contribute to inflammation and may weaken your immune response.
Greasy or Fried Foods: These are difficult to digest and can worsen nausea or other stomach issues.
Alcohol and Caffeine: These beverages are dehydrating and should be avoided during illness.

Nutritional Strategies for Different Infection Types

Different infections may present different nutritional challenges. Tailoring your approach can be beneficial.


Type of Infection	Primary Symptoms	Nutritional Focus	Example Foods	Avoid
Cold/Flu (Respiratory)	Nasal congestion, sore throat, fever, muscle aches	Hydration, soothing foods, nutrient support for immune function	Broth-based soups, hot teas with honey, citrus fruits, soft foods like oatmeal	Heavy meals, excessive dairy (if it thickens mucus)
Stomach Bug (Gastrointestinal)	Nausea, vomiting, diarrhea	Replenishing fluids/electrolytes, bland and gentle foods	BRAT diet (Bananas, Rice, Applesauce, Toast), clear broths, crackers, ginger	Fatty, greasy, spicy foods, acidic juices, caffeine, and dairy initially
Bacterial Infection (e.g., Pneumonia)	Fever, increased metabolic rate, potential for significant nutrient depletion	Meeting increased caloric and protein needs, especially during recovery	Protein-rich foods like lean meat, fish, eggs, beans. Nutrient-dense smoothies and fortified foods	Calorie-poor foods, forcing large volumes of food at once

Conclusion: A Balanced Approach to Healing

When facing an infection, your body needs nutritional support to power your immune system and heal effectively. The simple answer to "should I eat more or less food during an infection?" is to prioritize consistent, gentle nutrition and ample hydration. Do not force yourself to eat large meals if your appetite is low, but also avoid fasting. Focus on small, frequent meals of easily digestible, nutrient-dense foods and plenty of fluids. Listening to your body's cues and providing it with the right fuel will help you get back on your feet sooner.

If your appetite doesn't return or your symptoms persist, it is important to consult a healthcare professional. For more general guidelines, the National Institutes of Health (NIH) provides extensive resources on diet and immune function: https://ods.od.nih.gov/factsheets/ImmuneFunction-HealthProfessional/.

Frequently Asked Questions

No, you should not force yourself to eat if you feel uncomfortable or nauseous. It is more important to stay hydrated with fluids. While your body needs nutrients for recovery, it can draw on energy reserves for a short period. Focus on small, frequent, and easily digestible meals rather than forcing large ones.

No, this is a myth. Regardless of whether you have a cold or a fever, your body needs energy and nutrients to fuel the immune system and promote healing. Fasting is not recommended when sick, as it can deplete your body of vital resources.

The single most important thing to consume is fluids to stay hydrated. Many infections lead to fevers, sweating, or vomiting, all of which cause fluid loss. Proper hydration supports immune function, thins mucus, and helps regulate body temperature.

Appetite loss is a natural response to infection. Your immune system releases chemicals called cytokines, which signal the brain to suppress appetite. This is a mechanism to conserve the energy your body would use for digestion and redirect it toward fighting the infection.

For respiratory infections, opt for warm broths or soups, hot teas with honey and lemon, and fruits high in Vitamin C like oranges and strawberries. These options provide hydration, nutrients, and can help soothe a sore throat and congestion.

If you have a stomach bug, focus on bland, easy-to-digest foods to start. The BRAT diet (bananas, rice, applesauce, and toast) is a classic choice. Clear broths, crackers, and ginger for nausea are also beneficial. Avoid greasy, spicy, and acidic foods.

Protein is extremely important for recovery. It provides the amino acids needed to build and repair body tissues, produce antibodies, and create new immune cells. Consuming lean proteins like chicken, fish, eggs, and beans can significantly aid your healing process.