You’ve probably heard your grandmother warn, “feed a cold, starve a fever,” while you were neck-high under the covers stuffed up and miserable. Or was it “starve a cold, feed a fever”? Whichever it was, is there truth any truth to these kindly admonishments?
Evidence for the Health Claim
The idea of feeding a cold and starving a fever most likely originated during the Middle Ages when people believed that there were two kinds of illnesses. The illnesses caused by low temperatures, such as a cold , needed to be “fueled,” so eating was recommended. Illnesses caused by high temperatures, such as a fever, needed to be cooled down, so refraining from eating was thought to deprive the furnace of energy.
Most doctors today reject this idea. Recently, however, a Dutch research team conducted a small, preliminary study that provides some indirect support for the old myth. Researchers asked six healthy male participants to fast overnight before providing them with a meal on one occasion and just water on another occasion. They found that the subjects’ immune systems responded differently under the conditions of feeding versus starvation. While these are intriguing findings, they say little about how a person suffering from a cold or a fever can expect to actually feel when fed or starved. Although the study was small and inconclusive, the idea that food consumption may have a short-lived effect on the immune system is a new one, as previous studies have focused on more long-term effects.
Evidence Against the Health Claim
Current medical opinion puts the “feed a cold, starve a fever” maxim in the same category as other medical advice from the Middle Ages–false and maybe even dangerous! An infection–particularly one associated with fevers– is no time to deny your body the nutrients and fluids it needs. Like any bodily system, the immune system requires energy to function properly. To provide an extreme example, severe malnutrition is the major risk factor for life-threatening consequences of serious infections in less developed countries. And, drinking fluids helps counter the dehydration caused by sweating and mucus production.
Colds and flu are caused by viruses, for which there is no cure. The best you can hope to do is support your immune system as it struggles to prevail. Fever or no, starving yourself is no way to show your support. Whether you’re thirsty or not, drink plenty of fluids. And, if you’re hungry–eat!