Forget apple pie. Ice cream is America’s national dessert. Thanks to Ronald Reagan, July is National Ice Cream Month and although ice cream has competition from frozen yogurt these days, it retains its crown as the most in-demand summer treat.

In a given week, 40 percent of Americans will eat ice cream. That’s a lot. To put it in perspective, that’s nearly as large a share as will drink coffee.

If you plan on indulging this summer, please keep the following in mind: the size of the bowl you serve it in (hopefully you are not spooning it directly from the container) and the size of the scoop you use influence how much you eat. Why? Because most people eat what is in front of them. This is especially true when it comes to ice cream. Whatever the portion size—big or small—you are going to polish it off.

Consider the following: a person with tremendous self-discipline decides to eat half of a bowl of ice cream. The size of that bowl matters a great deal. Half of a large bowl versus half of a small bowl is very different indeed. Along similar lines, a small scoop of ice cream in a small bowl looks just right, but the same amount in a massive bowl appears meager. So what do you do to make it look like the “right” amount? You add an extra scoop.

Researchers call this the “size-contrast bias”. We unconsciously eat more than what we plan or want to because of it. Even experts are vulnerable. In a study, nutritionists were unaware of having served themselves 53 percent more ice cream when they were given large bowls and large scoops.

The difference is cultural as well. Portions in France and Italy are smaller than those in the United States. For example, an ice cream in Paris consists of one or two golf-ball sized scoops. In New York City, a single scoop is the size of a grapefruit.

Perhaps the most effective way to tackle super-sized servings is to change one’s environment. No, this does not mean you have to move to France. As referenced in Portion Size Me: Downsizing Our Consumption Norms:

Is education the answer? The answer is not in telling clients to remind themselves not to overeat from large packages, large servings, and large dinnerware. The answer is for them to eliminate large packages, large servings, and large dinnerware from their lives. It is much easier for a person to change his or her environment than to change his or her thinking. We first need to change our personal environment. Only then do we change our minds.

My advice: Use giant bowls and spoons to encourage fruit and vegetable consumption and serve dessert in small bowls with tiny scoops.