Effects of Increased Beverage Size on Calories Consumed at a Meal
People who are served large portions of drinks at meals tend to drink more of the beverage, and drinking a large sweetened beverage such as soda can increase the total calories consumed at the meal by more than 25 percent, according to researchers at Pennsylvania State University.
With national consumption of sweetened beverages such as soda increasing by more than 100 percent since the late 1970s, paralleling increases in weight among both adults and children in that time, the researchers were examining whether portion sizes of drinks have an effect on people's total food and calorie intake at meals.
In the study of 33 men and women, participants ate lunch in a laboratory once a week for six weeks. At each meal, the same foods were served, but the beverage varied among cola, diet cola and water. Portion sizes of the drinks ranged between 12 ounces and 18 ounces.
The researchers found that being served a larger drink significantly increased the amount of the beverage the participants consumed at the meals, regardless of the type of beverage. Similarly, the amount of food the participants ate at each meal stayed the same no matter what type or size drink they were served, resulting in a significant increase in the total number of calories they consumed.
When served an 18-ounce soda, total calorie intake increased by 10 percent for women and 26 percent for men. "These results suggest that drinking caloric beverages is associated with excess energy intake at a meal, and that consuming larger portions of caloric beverages will result in increased energy intake from the beverage," the researchers write. "Replacing caloric beverages with low-calorie or noncaloric beverages can be an effective strategy for decreasing energy intake."