Should I Eat More Fat When Sick? A Nutritional Guide

December 19, 2025 •

4 min read

According to the Food and Agriculture Organization, adding some fat-rich food can be an easy way to increase energy when ill for several days, especially when appetite is low. But does this mean you should eat more fat when sick? The answer isn't a simple yes or no, as it largely depends on the type of fat and the severity of your illness.

Quick Summary

Fat plays a vital role in providing energy during illness, but the type and amount matter significantly. Healthy fats, such as those found in avocados and olive oil, can offer concentrated energy and support immune function. However, greasy, high-saturated-fat foods can worsen symptoms like nausea and diarrhea, making them best to avoid during recovery.

Key Points

Choose Healthy Fats: Prioritize nutrient-dense sources like avocados, olive oil, and salmon, which provide concentrated energy and anti-inflammatory benefits.
Avoid Greasy and Fried Foods: Heavily saturated and fried fats are hard to digest and can worsen symptoms like nausea and diarrhea when you're sick.
Energy Demands Increase During Illness: A fever raises your metabolic rate, increasing your body's calorie needs, and healthy fats are an efficient energy source to meet this demand.
Fat Aids Nutrient Absorption: Healthy fats help your body absorb fat-soluble vitamins (A, D, E, and K), which are crucial for a strong immune response.
Balance with Other Nutrients: Pair healthy fats with lean proteins, complex carbohydrates, and plenty of fluids for a complete, recovery-focused diet.
Opt for Small, Frequent Meals: When appetite is low, smaller portions consumed throughout the day are easier to tolerate and help maintain steady energy levels.

The Role of Fat in Fueling a Sick Body

When your body is fighting off an infection, its energy demands increase. A fever, for example, raises your metabolic rate, meaning your body burns more calories. Fat is a dense source of calories, providing nine calories per gram, compared to four per gram for carbohydrates and protein. This makes it an efficient way to get energy, which is crucial when your appetite is low. However, the key distinction is between healthy, easy-to-digest fats and greasy, heavy ones that can put additional strain on your digestive system.

Healthy Fats: A Friend to Your Immune System

Not all fats are created equal, especially when you're under the weather. Healthy fats, particularly monounsaturated and polyunsaturated fats, offer more than just calories. They possess anti-inflammatory properties and aid in the absorption of crucial fat-soluble vitamins (A, D, E, and K), which are vital for immune function. Omega-3 fatty acids, a type of polyunsaturated fat found in salmon and walnuts, are particularly noted for their anti-inflammatory effects.

Avocado: Creamy and soft, avocados are gentle on a sensitive stomach and packed with healthy fats, fiber, and vitamins.
Olive Oil: A drizzle of olive oil over steamed vegetables or rice provides a source of healthy monounsaturated fats without being difficult to digest.
Salmon: An excellent source of omega-3s and high-quality protein, which are both essential for recovery.
Nuts and Seeds: While generally good, start with small portions, as their high fiber content can be hard on the stomach initially. Ground flaxseeds or a spoonful of almond butter might be a gentler option.

Fats to Limit or Avoid When Sick

Greasy, fried, and heavily saturated fats are harder to digest. During an illness, your gastrointestinal (GI) system can be more sensitive, and these foods can trigger or worsen nausea, diarrhea, and stomach upset. Many processed foods, like cookies, pastries, and chips, fall into this category and also offer little nutritional value.

Fried Foods: French fries, fried chicken, and other deep-fried items can cause gastric distress and are difficult for a weakened system to process.
Full-Fat Dairy: While some dairy is fine, full-fat versions like heavy cream or some cheeses can be hard to digest and may be best avoided if you have an upset stomach.
Processed Snacks: Chips, pastries, and many other convenience snacks are often high in saturated and trans fats and low in essential nutrients.
Certain Meats: Fatty cuts of meat, sausages, and other processed meats are high in saturated fats and can be taxing on the digestive system during recovery.

Comparison of Fat Sources for Illness Recovery


Fat Source	Type of Fat	Impact on Digestion	Benefits for Illness
Olive Oil	Monounsaturated	Easy to digest	Provides concentrated calories, aids vitamin absorption.
Avocado	Monounsaturated	Easy to digest, soft	Nutrient-dense, provides fiber, anti-inflammatory.
Salmon	Polyunsaturated (Omega-3)	Moderate; depends on preparation	Anti-inflammatory, high-quality protein.
Butter	Saturated	Moderate; can be harder	Concentrated energy, but heavy on the stomach in large amounts.
Fried Foods	Saturated/Trans	Hard to digest	Can worsen nausea, cause stomach upset.

Nutritional Considerations During Illness

While fat is important for energy, a balanced approach to nutrition is essential for a speedy recovery. Pairing healthy fats with other nutrient-dense foods can maximize benefits without overwhelming your system. Focus on small, frequent meals to maintain a steady energy supply and avoid nausea.

The Importance of a Balanced Approach

Consuming a variety of foods ensures you get the necessary micronutrients. Broth-based soups, for example, provide hydration and electrolytes, while cooked vegetables offer vitamins and minerals. Some illness-specific nutritional needs include:

Hydration: Staying hydrated is paramount, especially with fever, vomiting, or diarrhea. Broths and herbal teas are excellent for this.
Protein: The body's protein needs increase during illness to help repair tissues and produce immune cells. Lean protein sources like eggs, chicken, and tofu are easily digestible options.
Probiotics: Foods like low-fat yogurt and kefir can support gut health, which is crucial for immune function.
Vitamins and Minerals: Ensure intake of immune-boosting nutrients like Vitamin C and Zinc, which can be found in fruits, vegetables, and some fortified foods.

Conclusion

To answer the question, "should I eat more fat when sick?" the guidance is nuanced. The body does require sufficient energy to power the immune system and aid recovery, especially during a fever. Healthy fats, such as those found in avocados and olive oil, are excellent for this purpose as they provide dense calories, aid nutrient absorption, and offer anti-inflammatory benefits. Conversely, heavy, greasy, or fried fats should be limited or avoided altogether, as they can be difficult to digest and exacerbate symptoms like nausea. The best approach is to focus on a balanced intake of easily digestible, nutrient-rich foods, including high-quality fats in moderation, to support your body's healing process. Listening to your body and opting for small, frequent, nourishing meals is key to a smooth recovery.

Levels Health offers a comprehensive guide to eating when you're sick, which corroborates the importance of balanced nutrient intake during recovery.

Frequently Asked Questions

No, not all fats are bad. The key is to choose healthy, easily digestible fats like those found in avocados and olive oil. You should avoid greasy, fried foods and those high in saturated fat, as they can be harder on your sensitive digestive system.

When you are sick, your body's immune system works harder to fight the infection. A fever, for instance, raises your metabolic rate, which increases the number of calories your body burns. This heightened activity requires more energy, which healthy fats can provide efficiently.

For a sore throat, focus on soft, soothing, and easy-to-swallow foods. Healthy fats from sources like avocado, smooth nut butters, or a little olive oil blended into a soup can be beneficial. Avoid anything greasy, crunchy, or spicy that might irritate your throat further.

Yes, heavy, greasy, and fried fatty foods are more difficult to digest and can very likely make nausea and stomach upset worse when you're ill. Stick to bland, low-fat, and easily digestible foods if you are experiencing nausea.

In moderation, a little butter on toast or in soup is generally acceptable, but it is high in saturated fat and can be hard to digest in large quantities. If you have an upset stomach, it may be better to opt for a drizzle of olive oil instead.

Healthy fats, particularly omega-3s, have anti-inflammatory effects and help the body absorb fat-soluble vitamins (A, D, E, K), which are essential for supporting immune function and helping your body recover.

When your appetite is very low, focus on small, nutrient-dense meals. A little bit of healthy fat from something like avocado or a smoothie with nut butter can provide concentrated energy without a large volume of food. It's important to provide your body with some energy to aid recovery, even if you can't eat a full meal.