Published December 5, 2023
8 min read
Chicken soup. Half a grapefruit. Steaming hot tea. When you’re sick everyone from grandma to the next-door neighbor has a helpful suggestion for food that will put you on the road to recovery. What should we make of this wisdom—do some foods really help us feel better, or even actually get better?
And if so, why does illness often stifle our appetite when we might think nutrition is needed most?
“When someone who is feeling ill loses their appetite, or their thirst, it’s typically a sign that their immune system is working in overdrive,” explains Colleen Tewksbury, a dietician and professor of nutrition science at the University of Pennsylvania. That’s a challenge, she adds, because our bodies need fluids, as well as proteins, carbohydrates, vitamins, and minerals. “If you don’t feel hungry or thirsty, you just feel awful and you’re trying to rest, it’s really difficult to meet those needs.”
(Got a cold? Here’s how your immune system is fighting it.)
But it can be important to try. “Balanced nutrition can speed up your recovery, increase energy levels, and help to build up your immune system,” says Shea Mills, a registered dietitian nutritionist at the Mayo Clinic in Phoenix. “Overall, it is important to consume a healthy, balanced diet when sick.”
Read on for expert guidance on the reasons why you might not feel like eating when you’re ill, and tips about what to eat and drink until you’re back on your feet.
Starve a fever?
The reasons why we often can’t stomach eating while we’re sick are complex and not entirely understood.
The immune system requires a lot of energy to fight infection, which is why it’s good to consume healthy food during illness. But Yale University immunobiologist Ruslan Medzhitov says our bodies are ultimately optimized not for making us feel better, but for survival—and they might not always perceive an infection as their greatest threat. “That’s what’s counterintuitive,” Medzhitov says.
Our bodies unconsciously calculate trade-offs that may include some evolutionary mismatches with modern life, like the costs and risks once associated with sourcing food. Before pizza delivery was an option, getting food while sick meant exposing a weakened body to encounters with predators. And finding food also meant exerting more energy. Though life has changed, some theorize that these evolutionary holdovers may still play a role in curbing our appetite during illness.
(7 herbs that may help fight cold and flu.)
The body also makes physiological tradeoffs to get energy during an illness, Medzhitov notes, and scientists are still exploring how they work. Normally, the body is fueled primarily by glucose from food. When fasting, including during illness, it taps into fatty acids as a stored source of high energy.

