Do You Burn More Calories When Sick?

Yes, when you’re not feeling well, your body typically ramps up its energy expenditure by burning more calories. Your body temperature can rise, and your metabolism may increase by around 10 to 13 percent. This heightened calorie burn is a result of the body’s efforts to combat the illness and support the recovery process. Being sick refers to experiencing an illness or health condition that affects your well-being and normal functioning. Common symptoms of being sick can include fever, cough, congestion, fatigue, body aches, and digestive disturbances. Being sick isn’t fun. It makes me feel weak, fragile, and vulnerable.

So, do you burn more calories when sick? Yes, being sick can lead to a higher calorie burn. This is due to an increase in your basal metabolic rate, as shown in a 2007 study by Eileen R. Gibney from the University of Cambridge.

In this article, we will explore several questions related to being sick and its potential impact on calorie burn. Specifically, we will address whether being sick burns calories, whether the body burns more calories when sick, whether higher calorie intake is needed during illness, and whether fever contributes to calorie burn.

Do you burn more calories when sick

Do you burn more calories when sick?

Yes, the human body tends to burn more calories when sick because it requires additional energy to combat the illness and facilitate recovery. A study by Dr. Leah MacDonald at La Trobe University in Melbourne, Australia, back in 2011, showed that calories do indeed play a crucial role in the battle against sickness.

The body’s metabolic heat production increases due to illness and fever, and having an adequate calorie intake improves the likelihood of effectively fighting off the virus.

Conversely, insufficient calorie consumption may lead to a lack of energy and potentially prolong the duration of sickness. Therefore, it is important to ensure that you provide your body with enough calories to support its increased energy demands when you are sick.

What are the changes in calorie expenditure when sick?

When sick, your body’s calorie expenditure typically increases as it works harder to fight off illness and maintain homeostasis. Here’s how it changes:

  1. Metabolic Rate Increase: To combat illness, the body’s metabolism speeds up, burning more calories to fuel the immune response.
  2. Core Temperature Rise: Fevers are common, raising the body’s temperature to help kill pathogens, which also ups calorie burn.
  3. Immune System Boost: Additional energy is used to produce vital immune cells and antibodies, increasing overall calorie expenditure.
  4. Protein Synthesis: The body needs more protein for repair and defense, leading to higher calorie usage.
  5. Cellular Metabolism Shifts: In response to pathogens, cellular processes adapt, potentially increasing calorie needs.

Dr. Juan Ochoa Gautier, a Medical Director from the intensive care unit in New Jersey, emphasizes the importance of increased calorie and protein intake during these times to support these heightened metabolic activities.

How many calories do you burn when you’re sick?

When you’re sick, your basal metabolic rate can increase by about 10 to 13 percent for each degree Celsius that your body temperature rises, according to Dr. Daren Heyland, a critical care doctor with extensive research experience. This could result in an additional burn of 100 to 200 calories for every 0.5°C increase in core body temperature, highlighting the body’s increased energy demands during illness.

Does your body burn more calories when sick with an infection?

Yes, when fighting an infection, your body tends to burn more calories. This is because the body increases its metabolism and undergoes various metabolic changes to maintain homeostasis in response to the presence of bacteria, viruses, yeast, fungi, or other microorganisms.

According to Alex Romanyukha, Ph.D., a senior health physicist at the Naval Dosimetry Center, the energy required to combat germs and bacteria is a natural response to illness and infection. These processes and the increased energy demand contribute to the body burning more calories during this time.

Does your body burn more calories when sick with a fever?

Yes, you do burn more calories when you have a fever. Research from Necker-Enfants Malades University Hospital shows a 16.2% increase in energy expenditure per degree of fever, indicating that a higher body temperature during illness leads to significantly more calories being burned as the body enters a hypermetabolic state to fight infection.

How many calories are burned when you’re sick with a fever?

When you’re sick with a fever, your body can burn up to 20% more calories than normal, as noted by Johns Hopkins. This increase in basal heat production ranges from 20-50%, and the body shifts from using glucose as its primary energy source to utilizing protein and fat, in part to reduce the glucose available for bacterial growth.

Does your body burn more calories when sick with a stomach virus?

When battling a stomach virus, your body’s metabolic rate increases, as evidenced by research like the study “Viral Gastroenteritis: Sickness Symptoms and Behavioral Responses” by Arash Hellysaz and colleagues, published in mBio.

This study suggests that the gut-brain axis influences sickness symptoms and could affect energy expenditure during infections. The research from Linköping University and other institutions supports the idea that the body expends more energy during illnesses such as rotavirus and norovirus infections, partly due to the immune response and fever.

Does your body burn more calories when sick with a chronic illness?

Yes, your body does burn more calories when sick with a chronic illness due to disturbances in energy homeostasis, leading to increased energy expenditure. According to a 2003 study by Rosemary A Richardson and H Isobel M Davidson from Queen Margaret University College, Edinburgh, chronic illnesses can result in a negative energy balance and loss of fat and lean tissue. Specific energy targets for diseases like chronic liver disease suggest a requirement of 147-168 kJ (35-40 kcal)/kg, indicating higher metabolic demands during illness.

Does your body burn more calories when sick with a headache?

Having a headache alone typically does not significantly increase calorie burn. Calorie expenditure is primarily influenced by factors such as physical activity, metabolic rate, and the body’s energy needs for various physiological processes. Headaches, while uncomfortable, generally do not require a significant increase in energy expenditure.

Does your body burn more calories when sick with the flu?

Yes, when you have the flu, you may burn more calories compared to when you are healthy. The flu is an illness that can cause fever, inflammation, and increased metabolic activity in the body. These factors can contribute to an increase in energy expenditure, leading to the burning of more calories.

However, the extent of calorie burning during the flu can vary depending on factors such as the severity of the illness, individual metabolism, and the body’s immune response. It’s important to note that the increase in calorie burning during the flu is generally modest and may not significantly impact overall weight loss or gain.

Does your body need more calories when sick?

When sick, the body’s calorie requirements are nuanced and depend on the illness and individual circumstances. Contrary to the old saying “Feed a cold, starve a fever,” both conditions require adequate nutrition and hydration. Shinobu Yamamoto, Ph.D., in a 2020 study published in Nutrition and Metabolic Insights, suggests that a slightly lower calorie intake than usual during illness may lead to better outcomes, including shorter hospital stays and lower mortality rates. However, it’s crucial to balance this approach and ensure sufficient calorie and protein intake to avoid negatively impacting the body’s healing process.

This video provides some insights about how many calories you should eat when sick.

Why does the human body need more calories when sick?

When sick, the human body needs more calories because it’s working harder to fight the illness and repair itself. This increased energy demand supports essential bodily functions and immune responses, helping in faster recovery. The extra calories are utilized in various healing processes and in strengthening the body’s defense mechanisms against the illness.

This graph illustrates what happens with your calorie needs when you’re sick.

  • Immune System Activation. When you’re sick, your immune system becomes highly active to fight off pathogens and restore health. This immune response requires additional energy in the form of calories to fuel immune cell function and the production of antibodies.
  • Increased Metabolic Rate. Illnesses, particularly fevers, can elevate your metabolic rate. This means your body burns more calories at rest to generate heat and support various physiological processes involved in combating the illness.
  • Tissue Repair and Recovery. Sickness often involves tissue damage or inflammation. Your body needs extra calories to support the repair and regeneration of damaged tissues, as well as to facilitate a speedy recovery.
  • Elevated Energy Demands. Being sick can result in general weakness, fatigue, and increased physical and mental stress. These factors can raise your body’s energy demands, requiring additional calories to meet the increased energy requirements.
  • Maintaining Nutritional Balance. Certain illnesses can disrupt your appetite and alter nutrient absorption and utilization. Consuming sufficient calories ensures that your body receives the necessary nutrients to support immune function, prevent muscle wasting, and maintain overall nutritional balance during sickness.

Do animals need more calories when sick?

Animals, specifically rodents in a 2011 study published in the American Journal of Physiology, may not necessarily need more calories when sick. This research showed that a 50% calorie restriction in mice suppressed sickness behavior, reduced fever duration, and prevented anorexia and cachexia after they were induced with sickness. These effects are thought to result from the modulation of inflammatory pathways, but further research is needed to see if this applies to other animals.

How many calories should you eat when sick?

When sick, the ideal calorie intake can vary, but Dr. Heyland suggests aiming for around 2,000 to 3,000 calories, depending on factors like body weight, lean body mass, and physical activity. Heavier individuals or those with more lean body mass may require more energy. Additionally, focusing on a healthy diet, incorporating more protein, fresh fruits, and leafy greens, can aid in feeling better during sickness, even if it doesn’t necessarily shorten the duration of the illness.

Should you count calories when sick?

No, counting calories when sick is generally not necessary; the focus should be on consuming quality, nutrient-rich foods to support your immune system. While those accustomed to counting calories may continue to do so for control over intake, it’s advisable for anyone not comfortable with this practice, or without specific weight goals, to avoid calorie counting during illness and prioritize nourishment and recovery.

Which diet should you follow when you are sick?

When you’re sick, it’s advisable to follow a diet that is easy on digestion, nutrient-rich, and keeps you hydrated. Examples of suitable diets include the BRAT diet (Bananas, Rice, Applesauce, Toast) for gastrointestinal issues, a high-protein and high-calorie diet for recovery and immune support, and a liquid diet (like broths and smoothies) if you have difficulty swallowing or need extra hydration. Each of these diets caters to different needs of your body during illness, focusing on gentle digestion, energy supply, and hydration.

Is it advisable to continue dieting while you’re sick?

No, it’s not recommended to continue dieting when you’re sick. Restricting calories during illness can negatively impact the recovery process, as your body needs more nutrients to combat the sickness. Factors like a heightened metabolic rate, elevated body temperature, and possible reduced nutrient absorption all increase the need for adequate nourishment. As Dr. MacDonald points out, insufficient calorie intake during illness can weaken the immune system’s defenses, making it harder for the body to fight off pathogens. Personal experiences often echo this, with many finding that a calorie deficit during sickness can slow down the recovery process.

What foods should you eat when you are sick?

When you’re sick, the foods you consume can have a significant impact on your well-being and immune system. Here are some recommended foods to help boost your immune system and aid in your recovery.

  • Garlic. Garlic acts as a natural antibiotic and can help combat viruses. Add 2-3 crushed garlic cloves to your meals, such as tomato and mushroom sauces.
  • Honey. Organic honey contains antibacterial and antimicrobial properties. Enjoy it in tea, milk, or warm water. You can also incorporate it into your salad with spices and paprika.
  • Chicken soup. Chicken broth is a classic choice when you’re sick. It helps keep you hydrated, provides electrolytes, and aids in removing pathogens from your body.
  • Protein. During times of inflammation, dietary proteins become crucial as glucose is not efficiently utilized for energy. Include protein-rich sources like poultry, fish, eggs, and dairy in each meal. Men should aim for two palms of high-protein foods, while women can opt for one palm. If you don’t have an appetite, consider making a protein shake with powder.
  • Vitamins and minerals. Essential vitamins like A, C, D, E, B12, B6, and B9 play a critical role in strengthening the immune system. Ensure your diet includes foods rich in these vitamins. Consider taking a multivitamin with minerals such as magnesium, copper, zinc, and iron to further support your immune system.
  • Probiotics. Foods rich in probiotics can help balance the gut bacteria, which is beneficial for overall health. Fermented products like kefir, sauerkraut, miso soup, and pickles are excellent sources of probiotics. Some people also enjoy wine, cheese, and olives, but remember to stay hydrated by drinking enough water.

By incorporating these foods into your diet when you’re sick, you can give your body the necessary nutrients to support your immune system and aid in a faster recovery.

What foods should you avoid when sick?

When you’re sick, certain foods can exacerbate your symptoms and make you feel worse. Here are some foods that should be avoided or consumed in moderation during illness or sickness:

  • Fatty foods: It’s best to steer clear of high-fat meals and foods rich in carbohydrates when you’re sick. Excessive fat consumption can be difficult to digest and put a strain on your gastrointestinal system, potentially leaving you feeling even more fatigued.
  • Sugary drinks: Highly processed fruit juices and sugary beverages should be avoided as they can slightly suppress your immune system. Instead, prioritize hydrating yourself with water. You can add a squeeze of lemon or grapefruit to your water, as these citrus fruits contain natural antioxidants.
  • Caffeine: While a cup of coffee can provide a temporary energy boost, it’s important to consume caffeine in moderation when you’re sick. Coffee can dehydrate the body, which is counterproductive when you need to stay hydrated to support your recovery. Opt for water and other calorie-free beverages throughout the day instead.

By avoiding or minimizing the consumption of fatty foods, sugary drinks, and excessive caffeine, you can help your body recover more effectively and manage your symptoms more comfortably during illness. Prioritizing hydration and nutrient-dense foods will support your overall well-being and aid in your recovery process.

Does your appetite change during sickness?

Yes, sickness often leads to changes in appetite. While some may feel hungrier due to an increase in metabolic rate from bacterial infections and associated pro-inflammatory cytokines, it’s more common to experience a decrease in appetite. A 1987 study in the International Journal of Epidemiology found that illnesses like upper respiratory infections and fevers can reduce appetite and food intake by 15-20%. This suggests that a suppressed appetite is a typical response to various illnesses, emphasizing the importance of focusing on nourishing foods and fluids for recovery, even with diminished appetite.

How does your appetite change during sickness?

“Inflammatory responses like fever, headache, myalgia, and malaise trigger the release of the TNF cytokine,” explains Dr. Viktor Peny, an infectious disease expert at Lund University in Sweden. “This cytokine can lead to long-term immune reactions that affect appetite and energy intake.”

“The immune system takes up a lot of energy to combat infectious diseases. So halting digestion, suppressing appetite, and moving all the resources to the battle seems like a logical move.”

“Nevertheless, eating nutritious food during times of sickness can add many benefits and speed up the recovery process,” says Dr. Peny.

How to eat when you are sick and have no appetite?

When you are sick and experiencing a lack of appetite, there are four effective approaches to ensure you still consume nourishing food:

  1. Opt for foods you enjoy. During this time, prioritize your favorite meals. This is not the moment for restrictive diets or calorie deficits. Additionally, communicate your food preferences to those around you.
  2. Eat small, frequent meals. Grazing throughout the day is beneficial. If consuming a full-cooked meal feels daunting, consider opting for yogurt or cereals instead.
  3. Incorporate snacks. Snacking throughout the day can be helpful, as a diverse range of snacks can enhance your sensory-specific satiety. Increasing variety in your snacks can stimulate your appetite. One recommended protein-packed snack option is Jack Links.
  4. Experiment with smoothies. Smoothies are an excellent choice as they can be both delicious and nutritious, while also being easy to consume. Get creative by adding fruits, milk, dark chocolate, and nuts to make your smoothie an exciting part of your day. However, it’s advisable to avoid pre-made smoothies that contain excessive amounts of simple sugars.

Michal Sieroslawski

Michal is a personal trainer and writer at Millennial Hawk. He holds a MSc in Sports and Exercise Science from the University of Central Lancashire. He is an exercise physiologist who enjoys learning about the latest trends in exercise and sports nutrition. Besides his passion for health and fitness, he loves cycling, exploring new hiking trails, and coaching youth soccer teams on weekends.

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