Should You Eat More When You're Sick?

January 11, 2026 •

4 min read

According to a 2017 study from the Salk Institute, the body's response to infection is complex, and contrary to some long-held beliefs, eating habits should change depending on the type of illness. Your body is a machine, and when it's under attack, it needs specific fuel to fight back. However, the 'feed a cold, starve a fever' adage isn't the full picture and can be misleading, so understanding your body's specific needs is key to a swift recovery.

Quick Summary

The debate over eating more or less when unwell depends on the type of illness, with nutrition providing crucial fuel for the immune system while hydration remains a constant priority. While a fever increases calorie needs, a reduced appetite with a cold is often the body's natural response to conserve energy for healing. Listen to your body, focusing on nutrient-rich foods and plenty of fluids to support your recovery.

Key Points

Nutrient Needs Change: Your body's demand for calories increases with a fever to power the immune response, while a lowered appetite with a cold is often a natural way to conserve energy.
Hydration is Key: Dehydration is a major risk when sick. Focus on drinking plenty of fluids like water, broths, and herbal teas, especially with fever, vomiting, or diarrhea.
Eat Easily Digested Foods: When your appetite is low, choose bland, simple foods like bananas, rice, toast, and oatmeal that are gentle on your stomach.
Don't Force It: If you are nauseous, don't force yourself to eat large meals. Small, frequent, nutritious meals or liquid foods like smoothies and soups are more beneficial.
Prioritize Protein: Protein is vital for immune function and preserving muscle mass, which your body can break down for energy when you're ill. Good sources include chicken, eggs, and yogurt.

Your body’s energy needs change when you’re sick

When you're under the weather, your body's energy demands shift dramatically. For instance, a fever significantly increases your body's metabolic rate, demanding more calories to fuel the immune response. The immune system works overtime to produce white blood cells and fight off pathogens, a process that requires a substantial amount of energy. A fever can raise your body's energy needs by 10–13% for every 1°C increase in temperature. This is why eating enough, and the right kind of food, is so important when you have a fever. However, with other illnesses like a cold, a decreased appetite might be a natural response to conserve energy for the immune system. It's crucial to understand the signals your body is sending and respond appropriately with nutrient-dense foods and, most importantly, ample hydration.

The crucial role of hydration

Dehydration is a serious risk when sick, especially with a fever, vomiting, or diarrhea. Replenishing lost fluids and electrolytes is arguably more important than focusing solely on calorie intake, particularly during the initial stages of a severe illness. Fluids help thin mucus, soothe a sore throat, and keep your body's essential systems functioning correctly.

Hydration strategies when sick:

Water: The gold standard for hydration. Drink small sips regularly throughout the day.
Broth-based soups: A comforting way to get both fluids and electrolytes, like in a classic chicken noodle soup.
Herbal teas: Warm herbal teas, especially with ginger or honey, can soothe a sore throat and provide hydration.
Electrolyte drinks: Consider an oral rehydration solution if you are losing significant fluids through vomiting or diarrhea.
Popsicles or ice cubes: For those with a sore throat or extreme nausea, these can be a gentle way to rehydrate.

What to eat when your appetite is low

When you feel nauseous or have a sore throat, heavy meals might be unappealing. In these cases, opting for smaller, more frequent meals of easily digestible, bland foods is a good strategy.

Easy-to-digest food choices:

Bananas, rice, applesauce, and toast (BRAT diet): This classic combination is gentle on an upset stomach.
Oatmeal: A soothing source of fiber and essential minerals like iron and zinc.
Mashed potatoes: A comforting and simple source of energy.
Eggs: Poached or scrambled eggs are a great way to get easy-to-digest protein.
Yogurt with live cultures: The probiotics can aid gut health, which is a major part of the immune system.

Table: Best foods for different types of illness


Illness Symptom	Recommended Foods	Foods to Avoid
Fever	Soups, broths, electrolyte drinks, fruits and vegetables high in Vitamin C	Alcohol, caffeine, greasy or heavy foods
Sore Throat	Warm broths, herbal teas with honey, soft foods (oatmeal, mashed potatoes, yogurt)	Hard, scratchy foods (chips, crackers), citrus fruits if they cause irritation
Stomach Bug (Nausea/Vomiting)	Bland foods (BRAT diet), ginger tea, peppermint tea, clear fluids	Greasy, spicy, high-sugar foods, and caffeine
Cold/Congestion	Hot tea, chicken soup, garlic, ginger, vitamin C-rich fruits and veggies	Dairy products (can thicken mucus for some), excess sugar

The importance of protein during illness

When your body is fighting an infection, it can break down muscle tissue for energy, a process that is accelerated by insufficient calorie intake. This is why consuming enough protein is essential to help your body preserve muscle mass and support the production of antibodies and other immune cells. Good protein sources include chicken, fish, eggs, yogurt, and legumes. For those with low appetite, adding protein powder to a smoothie or yogurt can be an easy way to boost intake.

What if you just don’t feel like eating?

It is common to have a decreased appetite when ill. While it's important not to force yourself to eat if you feel nauseous, going without fuel for extended periods can slow your recovery. The key is to eat small, nourishing meals regularly, rather than trying to eat three large ones. Focus on nutrient-dense liquids like soups, smoothies, and juices to ensure you are getting vitamins and minerals, even if you can't tolerate solids. Your immune system relies on this constant supply of nutrients to function effectively and get you back on your feet faster.

Conclusion: Listen to your body and prioritize hydration

The old saying, "feed a cold, starve a fever" is an oversimplification. The reality is more nuanced: your body's energy needs differ based on your specific symptoms, but the need for proper nutrition and hydration is constant. A fever increases calorie burn, requiring more energy, while a low appetite during a cold might be your body conserving resources. The most critical takeaway is to listen to your body and prioritize fluids, especially if you have a fever, vomiting, or diarrhea. Focus on nutrient-dense, easy-to-digest foods and aim for small, frequent meals if your appetite is low. By providing your immune system with the right fuel, you can aid your body’s natural healing process and recover more quickly. Remember, consistency in hydration and light nutrition is better than forcing yourself to eat heavy meals you can't tolerate.

For more information on nutritional support during illness, consult with a healthcare professional or visit a trusted resource like MedlinePlus.(https://medlineplus.gov/ency/patientinstructions/000035.htm).

Frequently Asked Questions

No, the phrase is a misleading oversimplification. While your appetite might naturally decrease with a cold, your body still needs nutrients and, crucially, increased calories when you have a fever to support the elevated metabolic rate from the immune response.

Staying hydrated is the most critical aspect of recovery, especially with a fever or gastrointestinal symptoms. Drinking plenty of fluids like water, broth, and electrolyte drinks is essential to prevent dehydration and help your body function properly.

If you have no appetite, don't force yourself to eat large meals. Instead, focus on small, frequent servings of bland, easy-to-digest foods like toast or soup. Nutrient-dense fluids such as smoothies or broths are also excellent options to get essential vitamins and energy.

While no single food can instantly cure an illness, consuming nutrient-rich foods can support your immune system and potentially aid a faster recovery. Foods high in vitamins C, D, and Zinc, such as citrus fruits, leafy greens, and yogurt, are beneficial.

Avoid foods that are heavy, greasy, or high in added sugar, as they can cause inflammation and weaken your immune response. Alcohol and excessive caffeine should also be avoided as they can cause dehydration.

If you feel nauseous, try bland, cold foods that have less odor, such as popsicles or yogurt. Ginger tea is also known to soothe an upset stomach. Sip on clear fluids and focus on small, protein-rich snacks like plain chicken or scrambled eggs when you can tolerate them.

Chicken soup isn't a magical cure, but it is effective due to its ingredients. The warm broth helps hydrate and soothe a sore throat, while the steam can help clear congestion. The vegetables and chicken provide a source of nutrients and protein.