That tall glass of sweet iced tea (not to mention soda, fruit punch, specialty coffee and sports drink) sure does taste good going down.

But if you're trying to lose weight, those sugary drinks could sabotage your efforts.

Louie Favorite / AJC (ENLARGE)

Watch what you eat, and drink. A 20-ounce serving of sweet tea adds about 240 calories to your daily count.

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"Adults will say, 'I can't understand why I gain weight. I don't eat much,'" says Barbi Moore, nutrition educator for the Jefferson County (Ala.) Health Department. "Then I find out they drink a gallon of sweet tea a day."

A 20-ounce serving of sweet tea, for example, adds about 240 calories to your daily count. A 32-ounce soft drink packs a 300-plus calorie punch. (Adult females typically require 1,600 to 2,400 calories a day to maintain weight, according to the U.S. Department of Health and Human Services. Adult males typically require 2,000 to 3,000 calories.)

Even so-called health drinks, such as energy drinks or vitamin waters, can add unnecessary calories, health experts say.

"I think they're mostly expensive nonsense," says Philip Wood, author of "How Fat Works" and professor of genetics, nutrition sciences and physiology/biophysics at the University of Alabama at Birmingham.

If you're not an endurance or professional athlete, you probably don't need to drink sports drinks, either.

"Good old water will take care of most of your needs," Wood says.

Liquid calories don't tend to satisfy hunger, either, says Debbie Strong, a registered dietitian and program director for UAB's EatRight Weight Management Services.

"You don't get the chewing, you don't get the fiber, the things that 'fill' you," she says.

If you do choose to drink sugared drinks, limit the amounts, Wood says, and check the labels. For example, a 16-ounce can of energy drink might indicate there are 112 calories in a serving, but the can might contain two servings, or 224 calories. And it's hard to toss a drink when it's half-full.

"Everybody I know who opens a can of something drinks all of it," Wood says.

As for diet drinks, a couple of recent studies question whether they can actually hinder weight loss. The jury's still out, experts say. In the meantime, go easy.

"Drinking a reasonable amount of diet soda a day, such as a can or two, isn't likely to hurt you," Moore says.

Milk and 100 percent fruit juices, in limited quantities, can be healthful fluid choices, diet experts say.

But water should make up the bulk of your liquid intake, they say. It's calorie-free, and essential for good health (although, sadly, it won't "flush fat," despite rumors to the contrary).

"Fat is water-insoluble," says Wood. "You can't drink enough water to flush out fat."

You lose about eight cups of water a day, through your skin, exhalation and urine, Wood says. If you work out, water loss can double. The old adage, then, of drinking eight cups of water a day is about right, unless you work out. Even walking around in hot weather, though, can deplete your water supply, and thirst isn't always a reliable indicator that you're getting dehydrated.

"We may want to drink water as we go along in situations like that," Wood says.

The easiest way to gauge whether you're hydrated is through your urine, unless you're taking medications or eating foods, such as beets, that could alter the color, says Strong.

"If it's light, you're hydrated," she says. "If it's dark yellow, you're not hydrated."