These days, the average American household obtains more than 20 percent of its daily calories from beverages. On average, soft drinks account for 8 percent of adolescents' calorie intake.

Why fret: The rise in beverage consumption has mirrored the country's tramp toward rounder figures. “Satiety is less when you drink calories versus eating the same calories in foods because drinks empty from the stomach quicker,” says Phillips. “The extra calories from liquids can easily exceed what the body can use.” The worst offenders are “liquid candy” like soda and energy, sport, and sweetened fruit drinks. In a study published in the American Journal of Clinical Nutrition, Harvard researchers confirmed that a greater intake of these beverages leads to weight gain in adults and children. “Plus, most sweetened drinks don't have much nutritional value,” says Ayoob. Though they contain important vitamins, fruit juices such as orange, cranberry, and apple still pack a lot of concentrated sugar.

Try this: Phillips recommends limiting empty-calorie sweetened beverages and replacing them with unsweetened choices like low-fat milk, homemade iced teas, and water jazzed up with lemon or lime. Keep daily intake of fruit juice to 4-8 ounces, and focus on eating whole fruits instead. “You can also freeze fruit juice in ice-cube trays,” says Phillips. “Pop these into water for a hint of sweet flavor.” Send your children to school or camp with a reusable, BPA-free water container (stainless steel works well) so they get in the aqua habit. And consider stocking the fridge with refreshing, potassium-rich coconut water.