How much protein do you need for an infection?

October 23, 2025 •

3 min read

During an infection, the body's metabolic demands increase significantly, which can double or more the amount of protein required compared to a healthy state. Understanding how much protein do you need for an infection is key to supporting your immune system and accelerating recovery.

Quick Summary

Infection significantly increases the body's demand for protein to support immune function, tissue repair, and combat muscle breakdown. The amount required varies based on illness severity, ranging from 1.2 to 2.0 grams of protein per kilogram of body weight or higher in severe cases. Adequate protein intake is vital for recovery and minimizing muscle wasting.

Key Points

Increased Needs: During an infection, the body's protein requirement increases significantly to support the immune system and repair tissues.
Combat Muscle Loss: Sufficient protein intake helps prevent the body from breaking down its own muscle tissue for fuel during illness, a process known as catabolism.
Dosage Varies by Severity: Mild infections may require 1.2 g/kg/day of protein, while severe cases can demand 1.5–2.0+ g/kg/day.
Pair with Calories: Protein is used effectively for recovery when paired with adequate overall caloric intake from carbohydrates and fats; otherwise, it's burned for energy.
Best Sources: Focus on high-quality proteins from lean meats, fish, eggs, dairy, beans, and lentils to provide the necessary amino acids.
Eat Frequently: Smaller, protein-rich meals and snacks are often better tolerated when appetite is reduced due to illness.

The Body's Response to Infection: Why Protein is Crucial

When your body fights an infection, it enters a hypermetabolic state. This means your metabolism speeds up to fuel the immune response, leading to increased energy expenditure and protein breakdown. Protein is not just for building muscle; it is the fundamental building block for a vast number of critical components required for fighting illness:

Antibodies: These specialized proteins are essential for identifying and neutralizing invading pathogens.
Cytokines: Protein messengers that regulate the immune response and inflammation.
White Blood Cells: Crucial for battling pathogens, these cells are made from amino acids, the components of protein.
Enzymes and Hormones: These are vital for regulating countless bodily functions that are thrown out of balance during illness.
Tissue Repair: As your body recovers, protein is needed to repair damaged tissues and cells.

Insufficient protein intake during this period can lead to muscle wasting (catabolism) as the body breaks down its own muscle tissue to access the amino acids it needs to fight the infection. This can prolong recovery, weaken the body, and increase the risk of complications.

How Protein Requirements Change During Illness

While a sedentary adult's baseline protein requirement is about 0.8 grams per kilogram of body weight per day, this figure increases substantially during infection. For mild to moderate infections, the need can increase to around 1.2 grams per kilogram. However, in severe illness or critical care situations, the required intake may rise to 1.5 to 2.0 grams per kilogram or even higher. This means a 150-pound (approx. 68 kg) person could need up to 136 grams of protein daily.

It is important to note that without sufficient total energy intake from carbohydrates and fats, the body will use protein for energy instead of for its reparative and immune-boosting functions. Therefore, a balanced diet is essential.

Comparing Protein Needs During Health and Infection


Factor	Healthy Sedentary Adult	Individual with Mild Infection	Individual with Severe Infection
Daily Protein Intake (per kg)	~0.8 g/kg	1.2 g/kg or more	1.5 - 2.0+ g/kg
Primary Role	Muscle maintenance, daily bodily functions	Enhanced immune function, tissue repair	Rapid tissue synthesis, combat muscle wasting
Focus	Meeting basic nutritional needs	Supporting recovery and immune system	Preventing severe catabolism and weakness
Energy Needs	Regular caloric intake	Increased caloric and protein needs	Significantly higher caloric and protein needs

Practical Steps to Increase Protein Intake

Prioritize Whole Food Sources: High-quality protein can be found in lean meats (chicken, turkey), fish (especially fatty fish like salmon for anti-inflammatory omega-3s), eggs, and dairy products (Greek yogurt, cottage cheese).
Explore Plant-Based Options: Beans, lentils, chickpeas, tofu, quinoa, and nuts are excellent sources for vegetarians and vegans.
Eat Smaller, More Frequent Meals: Appetite often decreases during illness. Spreading protein intake across several smaller meals or snacks throughout the day can make it easier to reach higher targets.
Try Smoothies and Shakes: For those with a sore throat or decreased appetite, a protein smoothie with added powders, yogurt, or soft fruits is an easy way to consume nutrients.
Consider Supplements: In some cases, and after consulting a healthcare professional, supplements like protein powders can help bridge the gap, particularly during severe illness when food intake is very low.
Address Taste Changes: Illness can affect taste. Experiment with different spices and preparation methods. Soft, comforting foods like soups made with chicken broth and shredded meat can be well-tolerated.

Conclusion: Fueling Your Body for a Stronger Recovery

Protein is an indispensable nutrient when fighting an infection. It provides the essential building blocks for your immune system's defense mechanisms and supports tissue repair, which is vital for a strong recovery. While the exact amount you need will depend on the severity of your illness and other individual factors, understanding that your body requires more than its baseline can help you make better nutritional choices. By focusing on high-quality, easily digestible protein sources and ensuring adequate calorie intake, you can provide your body with the fuel it needs to heal faster and get back to full strength. If you have a severe or prolonged illness, or are considering supplements, it is always best to consult a healthcare provider or a registered dietitian for personalized advice.

For more detailed nutritional guidelines, especially during critical illness, the American Society for Parenteral and Enteral Nutrition (ASPEN) offers comprehensive resources, such as their guidelines for critically ill patients.

Frequently Asked Questions

When you are sick with an infection, your body enters a hypermetabolic state to fight off the illness. It needs additional protein to produce immune cells, antibodies, and cytokines, and to repair damaged tissues.

For a severe infection, particularly in a critical care setting, protein needs can increase to 1.5 to 2.0 grams per kilogram of body weight per day or more. Always follow medical guidance in these situations.

Many people can get enough protein from a diet rich in high-quality sources like lean meats, fish, eggs, and dairy. However, if your appetite is poor or your illness is severe, a healthcare provider might recommend supplements.

Good options include protein-rich smoothies, Greek yogurt, cottage cheese, eggs, and chicken soup with shredded chicken. These are often easier to digest and more palatable when your appetite is low.

Without sufficient protein, your body may break down muscle tissue to get the amino acids it needs to function. This can lead to muscle wasting, weakness, and a prolonged recovery time.

Your body's need for protein remains elevated during the recovery (convalescence) phase. It is a critical period for rebuilding muscle and restoring strength.

While it's important to increase protein intake, excessive amounts are not recommended without medical supervision, particularly for individuals with kidney issues. A balanced diet with adequate calories is key to using protein effectively.

References

1
Guidelines for the Provision and Assessment of Nutrition Support Therapy in the Adult Critically Ill Patient