Millions of Americans are concerned about their weight and watch what they eat. But if you really want to lose weight, start watching what you drink.

"Believe it or not, more than 20 percent of our daily calories come from what we drink," says nutrition expert Susan Aaronson, M.S., R.D., of the University of Michigan Health System. "The World Health Organization recommends that we consume only 10 percent of our calories from liquids. So those extra calories from liquid beverages are adding to America's obesity epidemic, making it more difficult for people to lose weight."

Drink low−fat milk, which can save you hundreds of calories a day.

To help make healthier beverage choices, Aaronson offers the following tips:

• Avoid soda, which is full of empty calories; the average can of regular soda contains an amazing nine teaspoons of sugar.
• Choose the right fruit and vegetable juices. "Read the label carefully," cautions Aaronson. "If a juice label says that it's 'made with real fruit juice', it may actually contain less than 10 percent real juice and seven teaspoons of sugar. The best juice drinks are those that say they contain '100 percent juice.'"
• Drink low−fat milk, which can save you hundreds of calories a day. Milk contains vital nutrients like calcium, protein, vitamin D, and vitamin A that you won't find in other beverages. If you stick to 1 percent, 1/2 percent, or skim milk, you will still get the nutrients your body needs without the extra calories and fat.
• Limit sports and energy drinks; although sports drinks replenish your body with electrolytes and help you stay hydrated, they still contain a lot of calories. "Sports drinks were actually developed for endurance athletes," explains Aaronson. "So if you plan to exercise for more than one continuous hour, then sports drinks are for you."
• Limit alcohol. The average glass of wine has about 100 calories and a 12 oz. beer contains about 150 calories. Mixed drinks can have as many as 300 calories and frozen drinks such as daiquiris can have 500 or more calories.
• Drink water instead. "Water is the single healthiest beverage that we can consume," says Aaronson. The average adult should drink between 4 and 6 cups of water a day.