By Michelle Swartz

Ever hear the expression "too good to be true?" It's a common saying because it is proven true over and over again. In the case of energy drinks — drinks that promise a quick jolt — the same holds true. They may give you a boost of energy, but at what cost?

Energy drinks are popular, but don't believe all the hype. For one thing, some labels say they offer a competitive edge in sports or other physical activities. No matter what the label says, it can NOT make you a better athlete.

They can deliver a quick boost of energy but that's not the whole story. You will find that an energy drink is fine every once in a while, but consuming several cans a day can be extremely harmful.

What are energy drinks?

Energy drinks are beverages that contain large amounts of caffeine, sugar and other ingredients designed to temporarily perk you up.

Sold in most convenience stores, the drinks act as a stimulant to gain a burst of energy. That is why so many names of the drinks convey strength, speed and power. Some of the name: Red Bull, Monster, Full Throttle, Rock Star and Amp.

Ingredients

The canned beverage may look cool to buy, but take a minute to think about what you're drinking. You may get a temporary energy boost, but it's not a natural increase in energy. The "boost" is from large amounts of sugar and caffeine, which is not good for you. Large amounts of sugar cause weight gain.

Besides caffeine and sugar, energy drinks include B vitamins, amino acids and herbal stimulants.

Don't be fooled by the B vitamins because they are available only in small amounts. It only makes the drink appear healthier than it really is. B vitamins are needed to convert food into energy.

The drink contains sugar because it's a quick source of energy. And some contain guarana, a South American herb that provides an additional source of caffeine. It also contains taurine, an amino acid thought to enhance performance.

Be careful because the effects of combining all these ingredients have not been studied.

Energy drinks also contain high calories, which cause weight gain. Using these drinks may be good for athletes who burn lots of calories in their workouts, but you should be aware of the calories and sugar because they will both cause weight gain and tooth decay.

Careful of the caffeine

Energy drinks contain large amounts of caffeine.

What is caffeine? It's a natural chemical found in plants that makes you feel more awake and alert. It is found in common foods and beverages, such as coffee, soda and chocolate.

Caffeine is an addictive drug, which means if you consume too much you can become dependent on it. Even though it's not as harmful as other addictive drugs, like nicotine or cocaine, it does cause your heart to pump faster. This is why you should not be drinking energy drinks every day, and especially not several cans in a day.

Caffeine causes nervousness, an upset stomach, headaches and sleep problems.

The amount of caffeine in certain energy drinks:

• Red Bull contains nearly 80 mg of caffeine in each can. That is twice the caffeine in a can of Coke or Pepsi.
• Other energy drinks contain several times this amount. And the amount is not always indicated on the label. Others, however, do not contain any caffeine. Hair of the Dog, for example, doesn't have any.
• SoBe No Fear, in a 16-ounce can, contains 141 mg of caffeine. That is equivalent of nearly five cans of Coke.

Gulp!

Check out these side effects of drinking too many energy drinks.

A lot of caffeine, as in energy drinks, can be harmful. Taking in too much caffeine can cause:

• Nervousness
• Irritability
• Upset stomach
• Headaches
• Difficulty sleeping
• Difficulty concentrating
• Increased heart rate and blood pressure

Healthier ways to boost your energy

• Get adequate sleep
• Exercise regularly
• Eat a healthy diet
• Drink lots of water

By the numbers

• Sales of energy drinks in the U.S. were $3.5 million in 2005, according to Beverage Digest.
• Energy drinks are expensive. The average 8-oz can cost about $3 each.
• Two years ago, there were 10 brands of energy drinks. Today, there are hundreds available.

Sources: About.com, kidshealth.org, and NPR