Americans who have made a New Year’s resolution to lose weight should start thinking about more than what they eat, a beverage industry survey said on Monday.

The study, commissioned by the Milk Processor Education Program, found that liquids make up 22 percent of calories in the average American’s diet. But most Americans only count the calories they get from solid foods.

People just may not be aware how these calories are sneaking into their diet…and (they are) not understanding what an impact it has on body weight,” said Carolyn O’Neil, a dietitian, who is serving as a spokeswoman for the What America Drinks report.

Americans drink a daily average of 38 ounces (0.67 liters) of water, which contains no calories. Sugar-sweetened beverages such as soft drinks and teas were next on the list, at 17.5 ounces a day. Americans consumed an average of 7.5 ounces of milk and 8.9 ounces of coffee on a daily basis.

Soft drinks make up 6.4 percent of Americans’ total caloric intake but the percentage is even higher for teenagers. Soft drinks account for 10 percent of the calories in a male teenager’s diet and nearly 9 percent of a female teenager’s calories.

American soft drink makers such as PepsiCo Inc. and Coca-Cola Co. have been releasing healthier products in recent years to try and capitalize on health and wellness trends. Some school districts have removed machines that sell full calorie soft drinks from schools.

One third of Americans are obese by U.S. health standards, which measure a person’s body fat.