There’s a story about a guy who called his grandmother the first time he cooked a roast.“I did it just like you used to. First， I first 1）lopped of the ends of the roast， then 2）seasoned it， added onions and carrots， and put it in the oven for two hours. It was perfect.”“You cut off the ends？” she asked. “Didn’t you？” he 3）countered. “Only when the roast was too big to fit the pan，” she said.
Old wives’ tales are like that. They may have been useful at one time and may have some truth to them， but it’s probably gotten 4）garbled in translation from one generation to the next. After all， many of these “old wives” were midwives and healers who were valued medical practitioners. We shouldn’t be surprised to find some science in their advice.
1. Cats Kill Sleeping Babies by Stealing Their Breath
Cats have been seen 5）alternately as divine（the Egyptian goddess 6）Bastet took a 7）feline form） or evil （we all know black cats bring bad luck， right？）. If the myth that cats steal sleeping babies’ breath were true， it would definitely fit in with that darker image. However， no scientific study or verifiable accounts back up such stories. How did this myth start？ It’s possible that cats have 8）inadvertently contributed to 9）Sudden Infant Death Syndrome， or SIDS， in which an infant dies while sleeping for no known reason. Infants with 10）respiratory conditions or an underdeveloped wake-response reflex are known to be at greater risk of SIDS. If such a child rolled toward a cat in his sleep， or if a cat stretched a paw on the baby’s face， it might 11）impair breathing enough to cause death. Then again， the cat’s presence may have been pure coincidence.
2. You Should Starve a Fever and Feed a Cold
This old tale may be partly based on the medieval 12）theory of humours. The idea was that good mental and physical health depended on the balance of four body fluids， called humours： black bile， yellow bile， blood and 13）phlegm. A fever indicated an excess of blood， and the treatment included bleeding the patient―which， in retrospect， was not such good advice. 14）Fasting may have also been 15）prescribed as a way to slow down what seemed to be an overcharged 16）metabolism. Likewise， every 17）mucous mouthful a cold sufferer coughed up indicated an excess of phlegm. Phlegm was a 18）wintry humour， associated with depressed spirits and depressed metabolism. The logical remedy was to 19）stoke the bodily 20）furnace with food， which would also lift the spirits. When you’re sick with a cold or the flu， your body needs the nutrients of a balanced diet and energy from adequate 21）calories to fight off the infection， especially in the early stages of illness. There’s no medical advantage to undereating or overeating in either case. Staying well nourished and well 22）hydrated is the best advice. 二、挨饿治发烧，感冒得多吃
3. Eating Sugar Makes Kids Hyper
Like some other myths on our list， this one has enough 23）semblance of truth to sound legitimate. Simple sugars are pure calories （i.e.， energy）. They’re quickly digested and sent to the bloodstream. So a rush of energy in the blood should cause a rush of activity in the body. The science of sugar metabolism tells a different story， however. When sugars enter the bloodstream， they’re first sent to the muscles and internal organs for immediate use. Excess sugars are not“worked off”. They’re stored in the liver and muscles as 24）glycogen for later use. Sugary snacks and sodas are rightly blamed for their role in 25）obesity and tooth decay. But hyper behavior is one 26）rap you can’t pin on them―unless， of course， they’re 27）caffeinated products like cola or chocolate.
4. You Lose Most of Your Body Heat Through Your Head
You can trace this partial truth to experiments conducted in the Arctic by the United States military in the 1950s. Volunteers were adequately dressed from the shoulders down， but left bareheaded. Not surprisingly， that’s where most of their body heat escaped―up to 80 of percent of the body heat they lost， according to the earliest reports. Initially， you do lose more heat through the head―up to 50 percent， similar to what the Survival Manual says. As the activity continues， however， the blood vessels near the skin in the rest of the body 28）dilate， allowing more blood to flow throughout the body and reducing the flow to the brain. Meanwhile， the 29）proximity of the vessels to the skin cools the blood to keep you from overheating. Heat loss through the head returns to about 7 percent. It’s still a good idea to cover the head in cold weather， of course， just like every other part of your body.