'20/20' Takes on Summertime Myths

The rituals of summer are in full swing. Bodies are tanner, blonds are suspiciously blonder, and the smell of barbecue is in the air. As you head out to the beach, are you worried more about sharks than sunburn? Do you wait half an hour after eating before you hit the water? You may want to rethink some of your summertime.

Here are a few of the summertime myths "20/20" puts to rest in "Summertime: Myths, Lies and Straight Talk."

Swimming with the Sharks

In the past month, a 14-year-old girl was killed by a shark off the coast of Florida and a 16-year-old boy lost a leg in a shark attack near the same stretch of beach. Every summer, scary reports of shark attacks or shark-infested waters grab our attention.

These incidents get so much news coverage you'd think there were great whites, tiger sharks and bull sharks lurking near every beach, just waiting out here to grab unsuspecting surfers and swimmers. But just how dangerous are sharks, and how likely are we to be attacked at the beach?

"Your odds of being attacked are infinitesimally small. You have a better chance of going and buying a lottery ticket and winning than you do of encountering a shark -- far less dying," said George Burgess, a marine biologist and the director of the Florida program for shark research at the University of Florida. Burgess, who has more than 4,000 files on suspected and confirmed shark attacks dating back to the 16th century, added, "Put it in perspective. Worldwide, we have on average, about 75 attacks a year, resulting in less than 10 fatalities."

In fact, dogs kill twice as many people each year in the United States.

Our national obsession with sharks began 30 years ago, when the movie "Jaws" scared us to death. Burgess says we've had an irrational fear of the toothy sea predators ever since.

But experts say most so-called shark attacks are a case of mistaken identity. Most of the time, when a shark realizes the human isn't a fish it lets go.

"The average person going to the beach in Florida or in New Jersey, they don't need to be worried about shark attack. They just need to understand that it's a potential risk along with many other things," Burgess said.

So the risk for is minimal, but to make it even less likely that you'll have a "Jaws"-like experience, experts have a few suggestions:

Don't swim after dusk or before dawn.

Don't wear shiny jewelry that can be mistaken by sharks for fish scales.

Don't swim alone.

If you do happen to meet up with your worst nightmare, Burgess says you should fight back. "Be as strong as you possibly can. They respect power. They're a predator," he said.

"Hit him on the nose, but be accurate, because just south of the nose is the mouth," Burgess cautioned.

So is it a fact or a myth then that sharks are public enemy No. 1 at the beach?

Burgess says no. "I would say sunburn is probably public enemy No. 1," he said.

Lightning -- A Bigger Threat Than Shark Attacks

Where lightning is concerned, there is an entire catalog of myths. Here are just a few: Myth: Lightning never strikes twice in the same place.

Fact: It does, especially if it's a tall, isolated object such as the Empire State building, which is struck an estimated 25 times a year.

Myth: If it's not raining, you're safe from lightning.

Fact: Lightning can strike more than three miles from a thunderstorm.

"Lightning's got its own agenda and we don't have its behavior totally figured out yet," said Richard Kithil, founder of the National Lightning Safety Institute.

"I want to emphasize that no place outside is safe," he said. "We should avoid proximity to water. We should avoid proximity to metal objects. We should avoid proximity to electrical machinery or equipment," he said.

But what about your car? Are you safe inside that metal object?

Wendy Allen, an anchorwoman for Central Florida News was in her car when it was struck by lightning. "I just saw bright light. Intense light filled up my car for just a split second. But it was a deafening bang. And I knew," she recalled.

The antenna was destroyed and a tiny scorchmark on the trunk shows where the lightning exited after it fried the car's electrical system. There were burn marks on Allen's T-shirt where her seatbelt had been; and, in a story she taped afterward, she was still recovering from a burn on her lip.

"I was drinking bottled water while I was driving, so they think that I might have had a little bead of water on my lip and that the electricity arced up from the seatbelt up to my lip and it charred my lip," she told "20/20."

Otherwise, she was unhurt, because the lightning had arced around the car's body.

"You're much safer staying in the car than going outside to try to find some other place to go, said William Roeder, the Chief Staff Meteorologist at the high-tech 45th Weather Squadron at Patrick Air Force Base in Florida. Roeder is responsible for the weather safety of the space shuttle and other launches from nearby Cape Canaveral, including lightning detection.

His answer to our myth question is that it's true to say that your car does protect you from a lightning strike. Here's why.

"The metal shell conducts the electricity from the lightning on the outside of the metal. If you're inside, not touching anything that can pass to the outside, you're reasonably safe," he said.

But if you thought that being safe inside your car had anything to do with the rubber tires, you were wrong.

"Think about it," Roeder said. "Lightning has just pushed through 10, 20, 30 miles of air. You think two, two inches of rubber's gonna stop it? I don't think so. Lightning laughs at two inches of rubber."

And there are always exceptions to what's safe -- in this case, cars with fiberglass bodies, according to Kithil.

"This business of a car being a fully enclosed safe place only refers to metal vehicles. No convertibles, no golf carts, no riding mowers, things like that," he said.

If you do get caught in the open during a lightning storm, get away from trees and poles. Kithil recommends a method to make yourself less of a target. Crouch down, put your feet together and place your hands over your ears to minimize hearing damage from thunder.

Here are important tips if you are in your home during a lightning storm.

Turn off the computer; and stay away from appliances and plumbing.

Stay off the phone, although it is OK to use a cordless or cell phone, because they're not connected to outside wiring.

Wait at least 30 minutes after the thunder has stopped before resuming normal activities.

The Price Is Premium, But 'Gas Is Gas'

When you head out on vacation this summer, you'll probably spend big bucks filling your car's gas tank, while griping about the price. But a lot of you who are complaining could be spending less for your gas.

You have a choice of gas at the pump. The price of 93 octane premium is more than regular 87 octane -- about 20 cents more per gallon at many stations. Because premium costs more, a lot of people think it's better for their cars.

People told us premium gasoline gives them better gas mileage, more power and cleaner engines.

Regular gas, one woman told "20/20," "leaves a lot of gunk in your engine … That's what my daddy taught me."

But her daddy -- and many of you who buy premium -- are wasting your money.

NASCAR driver Joe Nemechek knows this. "Believe me, I've pumped gas in from about every gas station there's been in my personal cars. Whether it's around town or on vacation or wherever, you put the regular in there it keeps on running," he said. The NASCAR drivers, mechanics, and car makers will tell you that for 90 percent of the cars sold today, high octane is no better than regular gas. It won't give you better mileage, more power or a cleaner engine. NASCAR crew member Lisa Smokstad told us what every expert told us.

"It is a myth that cars run better on premium gas," she said.

Some cars do need higher octane -- older cars that knock, and cars with high-compression, high-revving engines like Ferraris, Bentleys, Jaguars, Acuras, Mercedes and Corvettes.

But 90 percent of new cars don't need it -- check your owner's manual.

The car manufacturers and every car expert we consulted told us that for most cars, high octane is a waste of money. Even the gas companies that sell the high-octane fuel -- and make more money off of it -- admit most people don't need it. But they don't go out of their way to tell you that.

Once you've figured out which octane to buy, does the brand matter? Are the well-known national brands better than the no-name brands, which are usually cheaper?

People we spoke to gave similar reasons for buying name-brand gasoline that they gave for buying high-octane gas. They believed the national brands were higher quality, and better for their cars.

But they may not know that all the gas, brand name and generic, comes from the same refineries. Brand names do use different additives, but it doesn't make them better for your car.

In 1996, the Federal Trade Commission forced Amoco, which denied any wrongdoing, to stop claiming in its ads that it was better than other brands without scientific evidence to back it up.

"It's a myth that brand-name gas is better than a no-name gas," said mechanic Dave Bowman, co-host of "Two Guys Garage" on cable TV's Speed channel.

"It doesn't make any difference whether you're buying a branded product or a no-name product," he said.

"The only difference is price."

The NASCAR drivers agree about that, too. "It's a myth, you don't need the high-octane gasoline, you don't need the, the name-brand stuff," said driver Jimmie Johnson.

Some of the fans have figured that out.

One man summed it up nicely for us. "The manufacturers and the gasoline dealers, they all want you to buy that expensive stuff. It all runs on the same stuff. Gas is gas."

Oysters as an Aphrodisiac?

Ah, the oyster! We've all heard what a hot commodity oysters will make you between the sheets.

The Oyster Bar in New York City serves thousands of raw oysters every day. Just why do people find them so sexy?

"It's a very sensual experience. I mean you don't chew an oyster. You kind of like swallow it down completely. And it's wonderful. And your mind sort of just wanders along to sex," said David Walters, who spoke to "20/20" at the landmark restaurant.

A recent study lent credence to that popular belief. Rats were injected with amino acids found in shellfish, and researchers found it caused them to release sex hormones.

However, one of the doctors involved in the study says there's no evidence that oysters are an aphrodisiac in human beings.

One of ABC News' medical consultants, Yale University's Dr. David Katz, agrees. "The new research is many steps away from showing that oysters are an aphrodisiac, or in any way enhance sexual performance," he said.

What about the people though who swear that oysters are an aphrodisiac?

"As of today, if we ask the question do we know that oysters are an aphrodisiac, or for that matter, any shellfish, we'd have to say, no, it's a myth," Katz said.

But what's not a myth is that eating raw shellfish can make you sick. The Centers for Disease Control and Prevention estimates that thousands of people get ill from eating shellfish every year, particularly oysters, and a handful die. But that in no way deters the faithful.

"My son was conceived the night my wife and I each downed a dozen oysters. So that's not completely scientific but it certainly passes an empirical test," said Walters.

"Are they an aphrodisiac because of properties in the oyster, per se? No. Regrettably, it's a myth. Unless, you think they're an aphrodisiac. Because if you think they will put you in the mood, they will put you in the mood," said Katz.

Do Blonds Have More Fun?

From Mae West to Marilyn Monroe to Farrah Fawcett to Pamela Anderson, blonds have embodied the notion of the sex symbol. But it was a Clairol hair color advertisement that raised the big question: Do blonds really have more fun?

"20/20" hired two actors to go platinum to find out, and came up with a very unscientific test using hidden cameras.

Actress Diedre Lorenz found lots of people willing to help a fair-haired maiden in distress. Some went beyond the call of duty, offering their phone numbers and to take her out for a drink.

Lorenz said she doesn't typically get the sort of attention that she received with her blond tresses.

What about a platinum-haired man? Actor Jake Mayers gave it a shot and said he felt "sexier, and I do feel more attractive."

While surveys say blonds are often perceived as "ditzy" but "glamorous," brunets are seen as "competent" and "trustworthy."

Posing as a dark-haired tourist, Jake felt he got less action but more respect.

As a brunette, Deirdre felt invisible. She got dramatically less attention than she did with her blond hair.

"Men basically were throwing their phone numbers, begging me for my phone number, wanted to take me out sightseeing, take me for drinks," she said. "Today, not an offer. Literally, I did not have an offer."

If it's any consolation, studies show women are nicer to brunettes.

Research shows men are twice as likely to help someone out if she's a blonde. Our experiment found blondes certainly turn more heads, and that may be the fun a lot of people are looking for.

But our testers say fun, like beauty, is in the eye of the beholder.

"If you want a lot of glances, blonds. If you want something deeper, perhaps brunets," Lorenz said.

And Mayers? As a blond he felt attractive and sexy, as a brunet he said he "felt real."

Is It Dangerous to Swim After Eating?

It's the danger in the water your mother warned you about: Swimming right after eating is dangerous and if you do it, you will get a cramp and maybe drown.

Dr. Tim Johnson asked a swimming class what they thought. They believed it. When he told them it was a myth, they didn't believe him.

Dr. Jane Katz has been inducted into the International Swimming Hall of Fame for her contributions as an expert on swimming. But even she can't convince this beginner's swim class at New York City's John Jay College that swimming after eating isn't dangerous.

Katz said, "Part of this myth, … is basically comfort, because after you eat you always get tired. The reason is of course your circulation is going to the intestines and sometimes if you try to exercise vigorously you get a stitch."

But even if you get a stitch, or a cramp, it's not life-threatening.

The American Red Cross agrees. We set up our own experiment with those skeptical swimmers. We had them climb out of the pool and eat a snack. We had them get back in the pool and swim vigorously.

Everybody in class felt fine. One swimmer even said he was hungry.

We tried a tougher test. We asked John Jay's varsity swim team to help. We wanted to see if they could still swim like elite athletes — after eating like couch potatoes.

They all ate a Quarter Pounder and french fries and then swam five laps of sprints.

Even after a heavy, high-fat meal, the swimmers did just fine in the pool.

So the message is: Listen to your body, not your mother. No one recommends you eat a five-course dinner and then swim a marathon. But splashing around or swimming slowly with a full belly is fine.

Testing Self-Tanners

"You get what you pay for" is a claim you often hear from sales people who want to sell you expensive things. Whether it's true or a myth depends on what they sell, of course. So "20/20" took a look at the new self-tanning creams. Are expensive brands better than the bargain brands?

QT was the first self-tanning product to hit the market. Unfortunately, it and the other early brands tended to make you look orange, kind of like a carrot. Today, fortunately, all of the sunless tanning products work better than QT.

Even the gods and goddesses of tanning -- the actors on "Baywatch" -- used them. The actors on the show all had deep California tans, but did you know their tans weren't real?

The whole cast used sunless tanners for all 12 years of filming. Actor David Hasselhoff told us, "People actually come up to me and ask if it is real. But it's not," he said.

The actors avoided the sun whenever they could. The cast let our cameras record them applying fake tanners, because they were concerned that some of their millions of fans were baking in the sun trying to look like them.

"Don't do it because you can use a self-tanner and you can look just as good," said actress Angelica Bridges.

But does it matter which self-tanner you use? Today there is a huge difference in price. Coppertone costs about a dollar an ounce but Chanel's self-tanner is $36 for a small tube -- about $20 an ounce. Does that mean it's better?

Dermatologist Darrell Rigel says probably not.

"There's really not much difference, since all of them have the same active ingredient," he said.

The ingredient that does the tanning is dihydroxyacetone, or DHA, a chemical derived from sugar. DHA is the active ingredient in all the tanning products, cheap and expensive.

"What it is is a stain of the skin. It stains the upper layer of the skin," Rigel said.

"20/20" tested five self-tanners on several people -- we put both cheap and expensive brands on their backs. All five tanners gave a natural-looking tan. We couldn't tell the difference. After all, DHA is DHA.

John Stossel confronted Susan McAlarney about that. McAlarney works for Chanel, which sells those $36 tubes, and she claims Chanel's self-tanners are worth more because they contain extra ingredients that will make you look better.

"Tomato extract, which helps brighten the skin. … We also include ingredients like copper pearl pigments, which basically are light-diffusing, and so lines look softer and smoother on the skin, which everybody wants," she said.

Rigel said he wasn't aware of any studies that supported McAlarney's claims and said, "I'm not sure what copper pearl pigments are, but it's not clear that that would make a difference."

Chanel says it has done studies that show that its product improves the "radiance of the complexion" and the "suppleness of the skin. Experts we consulted say these kinds of products all tan the same.

McAlarney said she found it "interesting" that we weren't able to tell the difference in the fake tans produced by the low-price and high-end tanners we tested. Some might call selling the same active ingredient for 17 times the price "a ripoff."