Do Energy, Sports Drinks Live Up To Hype?

The maker of a new energy drink claims drinking a single, 12-ounce serving could result in your body burning as many as 100 calories.

The company also says "Celsius" results in higher energy levels.

Manufacturers of most energy drinks assert they give you that "oomph" to help get you through the day.

But do they live up to their billing, and are they safe?

What about sports drinks and vitamin water?

On The Early Show Saturday Edition, medical correspondent Dr. Jennifer Ashton threw a bit of cold water on the claims.

Celsius, Inc. says it commissioned several blind studies that show drinking it before exercise can raise metabolism an average of 12 percent, burn more than 93 percent more fat than you otherwise would have, build 50 percent more muscle mass than without it, improve cardio-respiratory fitness and, of course, burn calories.

First of all, says Ashton, bear in mind that those studies were paid for by Celsius. And remember, even the Web site devoted to the drink says, "Celsius alone does not produce weight loss in the absence of a healthy diet and regular exercise." The claims, she told co-anchor Erica Hill, are "probably a little heavy on the marketing and a little lighter on the medicine." The bottom line, she told Hill, is, "You've got to take in less than you burn" to lose weight.

And, Ashton said, like many energy drinks, Celsius contains caffeine, and a lot of it. In fact, a can of Celsius contains the equivalent to two cups of coffee. There is some evidence that caffeine, which is a stimulant, can enhance performance and may rev up your metabolism in the short-term but, experts say, probably not over the long-term. Your body would probably adapt over time. We need some more independent studies before any real conclusions can be made, Ashton says.

More from a CBS News discussion with Ashton:

WE SEE A LOT OF THE SAME INGREDIENTS IN THESE DRINKS, SUCH AS "TAURINE," "GUARANA," "GREEN TEA LEAF EXTRACT," B-VITAMINS. WHAT DO THEY DO?

Guarana is a natural source of caffeine. Green Tea Leaf Extract, like caffeine, may have an effect on metabolism. Ginseng, Taurine, Gingko and B Vitamins are often thrown into these drinks, but there's little evidence that they offer any benefit for boosting energy or for weight loss. And this doesn't pertain to Celsius, which has very few calories, only 40, but -- some of them contain a lot of sugar and sodium.

THE BEST-KNOWN ENERGY DRINKS, SUCH AS RED BULL AND ROCKSTAR, HAVE ONE THING IN COMMON: THEY RELY HEAVILY ON CAFFEINE AS AN INGREDIENT. IS IT SAFE TO CONSUME ALL THAT CAFFEINE?

Safe? For the average healthy adult who uses them on an occasional basis, probably. But the additional caffeine may not be a good idea for some people, such as those with high blood pressure and women with osteoporosis. And these drinks are certainly not recommended for pregnant women, people with heart conditions, or children.

IS VITAMIN WATER BETTER THAN REGULAR WATER?

Waters infused with various vitamins are generally no better than regular water, and in some cases, may be worse, because they contain a lot of sugar. The amount of vitamins you get in a regular serving is a small fraction of what you really need in a day, and the additional sugar can sneak up on you. Some have more sugar than others, but in general, you think you're just drinking healthy water when in fact you're drinking in many more calories than you might realize. So, study the label carefully. And tap water usually contains more fluoride, which you need for good dental health.

HOW ABOUT SPORTS DRINKS, SUCH AS GATORADE?

If you're just doing mild to moderate exercise, you probably don't need a sports drink. But for people who engage in high-intensity workouts and people who sweat a lot, a sports drink may have a role. They provide hydration, fuel (in the form of sugar) and, more importantly, electrolytes such as sodium and potassium that athletes lose through sweat. They're also a good option for people with vomiting, say, from the stomach flu, who can't eat anything. They can help prevent dehydration, like some of the re-hydration solutions out there. Incidentally, Gatorade now has a sugar-free version, called "G2."

BOTTOM LINE, ARE THESE DRINKS NECESSARY, AND ARE THEY SAFE?

It depends. As for the weight loss and energy drinks, I hate to say it but -- we always go back to the basics. Regular exercise and a healthy diet are really the keys to losing weight and maintaining a healthy weight. And I overheard someone say you might as well just drink two cups of coffee and take a multivitamin instead. But these drinks deserve further study. As for the vitamin waters, you're better off sticking with plain water or a no-calorie flavored variety if you want something with taste. And as for sports drinks, they certainly have a place for people who engage in serious sweat-producing activities.