Next, the researchers looked at how much the average amount of calories consumed would change if some people switched from drinking a 32-ounce beverage to a 16-ounce drink.

They found that if all consumers who had been buying larger sizes switched to a single 16-ounce drink (and none bought two 16-ounce beverages), the average calorie intake would drop by 63 calories per meal.

If 40 percent of consumers switched to a single 16-ounce beverage, overall calorie consumption would still decrease by close to 10 calories. If 30 percent switched, no decrease would occur, the researchers said.