Should You Eat More Calories When Sick? A Nutritional Guide for Recovery

October 16, 2025 •

4 min read

For every 1°C increase in body temperature during illness, a person's energy expenditure can rise by about 10-13%. This increased metabolic demand begs the question: Should you eat more calories when sick? The answer is more nuanced than a simple yes or no, focusing less on quantity and more on nutrient quality and hydration.

Quick Summary

Your body's immune response burns more calories to fight illness, especially with a fever. The best approach is to focus on consuming nutrient-dense foods and fluids, listening to your appetite, and prioritizing hydration over forcing large meals.

Key Points

Metabolism Increases: Your body burns more calories when sick, especially with a fever, to power your immune system's fight against infection.
Hydration is Critical: Fluid loss from fever or vomiting makes staying hydrated with water, broth, or tea the top priority during illness.
Prioritize Nutrient-Dense Foods: Instead of focusing on calorie quantity, choose nutrient-rich foods like protein, fruits, and vegetables to support healing.
Eat Small, Frequent Meals: If your appetite is low, smaller portions throughout the day or nutrient-rich liquids are often easier to tolerate than large meals.
Myth of 'Starving a Fever': The old adage is outdated; modern medical advice recommends nourishing your body with fluids and food for both colds and fevers.
Avoid Inflammatory Foods: Sugary, greasy, and processed foods can increase inflammation and should be limited during illness.

The Science of Sickness: Increased Metabolic Demand

When you fall ill, your body's immune system kicks into high gear to fight off the infection, a process that requires a significant amount of energy. This is why you often feel tired and may even experience a temporary boost in your metabolic rate. Fever, in particular, is a major driver of this energy increase, as your body works harder to maintain an elevated temperature. Inflammation, another key component of the immune response, also raises your energy needs. However, this heightened activity doesn't necessarily mean you should start overeating. The focus should be on providing your body with the right fuel to support its healing processes without overburdening your digestive system.

More Than Just Calories: The Quality of Your Fuel

While it is true that your body requires more energy, not all calories are created equal when you are sick. Your body is working overtime and can't use food to build itself up in the same way as when you are healthy. Instead, it prioritizes nutrients for repairing tissues, producing immune cells, and supporting a robust immune response. If you have a low appetite and don't get enough fuel from your diet, your body may start breaking down muscle and protein stores for energy, which can prolong recovery. Therefore, it is crucial to focus on easily digestible, nutrient-dense foods rather than high-fat, high-sugar options, which can worsen inflammation and offer little nutritional value.

The Critical Importance of Hydration

Often more important than eating, staying hydrated is paramount when you're sick. Illnesses can cause significant fluid loss through fever-induced sweating, vomiting, or diarrhea. Dehydration can not only worsen your symptoms but also seriously hinder your body's ability to recover. Drinking plenty of fluids helps regulate your body temperature, thin mucus, flush out toxins, and transport essential nutrients.

Excellent sources of hydration include:

Water
Clear broths and soups
Herbal teas (e.g., ginger, chamomile)
Electrolyte-rich beverages (coconut water, sports drinks without excessive sugar)
Fruits and vegetables with high water content (melon, strawberries, cucumber)

Nutrients to Prioritize When Ill

Certain nutrients are particularly important for supporting your immune system during illness:

Protein: Essential for tissue repair and building antibodies. Include sources like lean chicken, fish, eggs, tofu, or yogurt. Protein also helps prevent muscle loss that can occur with prolonged bed rest.
Vitamins C and D: Vitamin C is a powerful antioxidant found in citrus fruits, berries, and bell peppers that supports immune function. Vitamin D also plays a critical role in immune health.
Zinc: This mineral is vital for immune cell function. Sources include nuts, seeds, legumes, and lean meat.
Antioxidants: Found in leafy greens and colorful fruits, antioxidants protect your cells from damage caused by inflammation.
Probiotics: Beneficial bacteria in yogurt and other fermented foods can support gut health and may boost immune function.

Strategies for a Low Appetite

It is common to lose your appetite when you are sick. Instead of forcing yourself to eat large meals, try these strategies to maintain your nutritional intake:

Eat small, frequent meals: Opt for five to six small meals throughout the day instead of three large ones. This is often easier on the stomach.
Make every bite count: Choose nutrient-dense foods that offer the most benefit in a smaller portion, such as smoothies, soups, and milkshakes with added protein powder or fat.
Don't forget fluids: If solid food is unappealing, liquid nutrition from broths, smoothies, or yogurt drinks can still provide calories and nutrients.
Go for soft, easy-to-digest foods: Bland foods like toast, rice, bananas, and applesauce can be gentle on an upset stomach.

The Truth Behind the Myth: Feeding a Cold vs. Starving a Fever

For generations, people have followed the adage of "feed a cold and starve a fever." However, medical experts now advise against this outdated approach. In both cases, your body needs proper nutrition and, most critically, hydration to support its healing processes. Restricting food during a fever deprives your body of the increased energy it requires to fight the infection. The focus should be on listening to your body's cues and providing it with the energy and nutrients it needs to recover, regardless of the specific symptoms.

Making Wise Food Choices: A Comparison Table

When you're ill, making thoughtful food choices can significantly impact your recovery. Here is a comparison of foods to prioritize and those to avoid.


Recommended Foods	Foods to Limit
Clear Broths and Soups: Hydrate and soothe symptoms.	Sugary Snacks and Drinks: Can cause inflammation and provide little nutrition.
Lean Proteins (Chicken, Fish, Eggs): Provide essential amino acids for repair.	Processed and Fatty Meats: Can be harder to digest and may promote inflammation.
Bland Carbohydrates (Toast, Rice, Oatmeal): Easy on the stomach and provide energy.	Spicy and Greasy Foods: Can irritate a sensitive digestive system.
Fruits and Vegetables (Citrus, Leafy Greens): Packed with vitamins, minerals, and antioxidants.	Caffeine and Alcohol: Can worsen dehydration.
Probiotic-Rich Foods (Yogurt): Supports gut health and immune function.	Excess Dairy: May cause some to produce more mucus, worsening congestion.
Ginger: Known for its anti-nausea effects.	Heavy, Rich Dishes: Harder to digest and can lead to sluggishness.

Conclusion: Listening to Your Body for Optimal Recovery

The short answer to the question, should you eat more calories when sick?, is that your body's needs increase, but it's not a license to overeat. Instead, focus on a strategic approach: prioritize hydration, choose nutrient-dense and easy-to-digest foods, and listen to your appetite. By doing so, you can provide your body with the energy and building blocks it needs to effectively fight off illness and speed up your recovery without placing additional stress on your system. Always consult a healthcare professional for specific dietary advice, especially for severe or chronic illness.

For more detailed information on preventing dehydration, refer to this authoritative resource from the Mayo Clinic: Dehydration - Symptoms & causes.

Frequently Asked Questions

Yes, a fever significantly increases your body's metabolic rate. For every 1°C increase in body temperature, your energy expenditure can rise by approximately 10-13%, requiring more fuel to support your immune system.

If you have a low appetite, focus on easy-to-digest, nutrient-rich foods like broths, smoothies, or soft, bland foods such as rice, toast, and bananas. Eating small, frequent meals throughout the day can also be more manageable than large ones.

No, this is a long-debunked myth. Medical experts advise that in both cases, your body needs adequate fluids and nutritious food to support the immune system and promote recovery. Restricting food during a fever is not recommended.

The best drinks include water, clear broths, herbal teas (like ginger or chamomile), and coconut water. For electrolyte replacement, low-sugar sports drinks can be helpful, especially if you have vomiting or diarrhea.

Protein provides the amino acids necessary for tissue repair, muscle maintenance, and creating immune system components like antibodies. Ensuring adequate protein intake helps prevent muscle breakdown and supports a more robust immune response.

Yes, certain foods can be counterproductive. Limiting or avoiding sugary snacks, processed foods, greasy items, spicy food, caffeine, and alcohol can help reduce inflammation and dehydration, which may otherwise prolong your recovery.

Yes, there is evidence that chicken soup can help. The warm broth helps hydrate and can relieve congestion. The chicken contains cysteine, an amino acid with anti-inflammatory and antiviral properties, and the meal as a whole provides essential nutrients.