When people are unwell, they often receive advice about foods and drinks that might help them feel better. Scientists are investigating whether specific nutrients can support the body during illness and why the body often loses its appetite at a time when it needs energy most. Colleen Tewksbury, a dietitian and professor of nutrition science at the University of Pennsylvania, explains that when someone is sick and loses their appetite or thirst, it usually means their immune system is working hard. However, meeting the body's needs for water, protein, carbohydrates, and vitamins becomes difficult when unwell. Shea Mills, an accredited dietitian at the Mayo Clinic in Phoenix, says that eating a balanced diet can help the body recover faster, boost energy levels, and strengthen the immune system. She emphasizes the importance of maintaining good nutrition even when sick. Ruslan Medzhitov, an immunobiologist at Yale University, explains that the immune system needs a lot of energy to fight infections, but it is not designed to make people feel better—it is focused on survival. He suggests that the body might not always see a simple infection as the biggest threat, which seems counterintuitive. The body makes unconscious decisions based on long-term evolution, which may not align with modern lifestyles. Historically, getting food while sick required more energy and put weakened bodies at risk. These evolutionary traits may still influence the loss of appetite when someone is ill. During illness, the body may shift its energy source from glucose to fatty acids, which can protect tissues and organs from inflammation caused by pathogens. However, this change may not help everyone in the same way. In a 2016 study, Medzhitov and his colleagues found that mice infected with the flu virus felt better when they ate, while those infected with Listeria bacteria felt better when they did not eat. Although this study does not mean that humans should starve bacteria and feed viruses, it shows the complex relationship between diet and illness. Tewksbury notes that people react differently to illness, as the body's response to stress varies. Nutrient needs also change depending on health status, such as during pregnancy, growth spurts, or when ill. Medzhitov acknowledges that the evolution of these preferences when sick depends on the illness, and this is not yet well understood. The right combination of nutrients to consume remains a complex question. Mills suggests eating smaller portions more frequently and including proteins, carbohydrates, and fruits or vegetables to maintain a good balance of nutrients. This idea contributes to the reputation of chicken soup as a potential remedy for illness. Tewksbury explains that broth-based soups contain vitamins, minerals, and electrolytes, and hot soups can help eliminate mucus in upper respiratory tract infections. They meet many criteria for aiding recovery. Mills highlights the importance of certain vitamins and minerals in a healthy diet for the sick. Vitamin C, found in fruits and vegetables, supports immune cells, and vitamin D can strengthen immune responses and reduce illness duration. Fatty fish, mushrooms, red meat, and some dairy products and cereals are sources of vitamin D. Hydration is a key element in fighting diseases, but it can be difficult when the body loses fluids due to vomiting, diarrhea, or sweating. Tewksbury recommends decaffeinated beverages, teas, water, 100% pure fruit juices, and electrolyte-rich drinks like coconut or cactus water. Dietary supplements can also help, such as zinc, which may reduce the intensity and duration of certain upper respiratory tract infections when taken early. However, supplements should be used cautiously and under the guidance of a healthcare professional. Some foods can alleviate symptoms, such as warm tea or cold ice cream for sore throats. However, certain foods like peppers containing capsaicin can thin mucus but may also cause nausea or increase mucus production. Cold drinks can help relieve sore throats but may worsen mucus production in some cases. Tewksbury suggests that the best approach is to try different foods and observe what helps, as there is no one-size-fits-all answer. Medzhitov believes that the best strategy is to listen to the body and follow cravings, as they may reflect what the body needs based on evolutionary signals. In conclusion, while foods may not cure diseases, they can help alleviate symptoms and support recovery. The relationship between diet, illness, and appetite remains complex and varies from person to person.