1. True or false: If you give a kid sugar, he'll get hyper.
2. True or false: Eat sugar, and your energy may slump.
3. True or false: It's a good idea to drink eight glasses of plain water every day.
With so many myths in our lives, perhaps the surprise is that one of these familiar theories is actually true.
Parents say the first one all the time: Sugar makes kids wild and crazy. Even some kids say it. "I go really nuts when I have candy," one girl told ABC News. Another told us it affects her so strongly that she'll change her behavior, "like sometimes I'm like oh, my God, I'll clean my room." Oh, my God, indeed.
Not that it's limited to the young. One woman told us, "You can have like one candy bar and be off-the-wall."
But the idea that sugar causes hyperactivity is a myth. "The research is very clear," said Cathy Nonas, a dietician at New York's North General Hospital. "Sugar does not make a child 'hyperactive.'"
Many studies back her up. In one, published in the New England Journal of Medicine, some kids ate sugared foods while others got foods with artificial sweeteners.
Their parents and the researchers didn't know who was eating sugar and who wasn't. The researchers monitored the kids for things like irritability and hyperactivity. They found no difference.
"There is no such thing as a 'sugar high,'" Nonas said. "And there is no such thing, as 'sugar making you nuts.' There just isn't."
I found that hard to believe. I've seen kids go crazy at parties. Isn't that because the sugar kicks in?
As one parent put it. "They are hyper because they are excited. Because they have freedom. Because there is 20 kids, crowding around each other."
In other words, because it's a party.
The studies also say that if food has any effect, it could be the caffeine in chocolate and soda that's giving you the buzz, not the sugar.
Still, even older students swear sugar helps them in school.
But the opposite is likely to be true. Said Nonas: "We tell kids, if they want to do well on a test, not to eat sugar. Even though it increases your blood sugar, which is why I think there is some confusion -- it drops it down, pretty quickly, so that you have this kind of 'lull.'"
As one man put it, "Once it's over, you kind of, like, crash."
That's right: Some research shows that instead of jacking you up, sugar may actually calm you down.
And the mantra of the health and beauty world, "eight by eight," which means you should drink eight 8 oz. glasses of water every day? Lots of people believe it. Some schools require kids to carry bottled water around with them. But it's another myth.
Dr. Heinz Valtin, professor emeritus of the Dartmouth Medical School, spent his life studying the right balance of water in our bodies, so there's no evidence that supports the "8 x 8" idea.
"I drink about five or six glasses per day -- only one of them is water," he said.
Much of the fluid we need comes from, of all things, food.
"Even a slice of white bread is more than 30 percent water," he said. "It's lots of water, 80 to 90 percent in vegetables and fruits."
Valtin acknowledges that drinking water is not a bad idea. "What's wrong with the myth is that the recommendation is universal that every last one of us, including, as one article said, couch potatoes, must drink at least eight, 8-ounce glasses per day," he said.
The Institute of Medicine's food and nutrition board agrees with Valtin. It says drinking eight glasses of water is not necessary, because we get plenty of fluid from our food. When your body does need more fluid, it has a marvelous mechanism for telling you to drink up. It's called "thirst."