July 25, 2006 -- Alert the portion-size patrol: Big plates and jumbo-sized serving spoons might secretly sabotage your diet.
Even nutrition experts accidentally supersize their food portions when using big serving spoons, especially if they're spooning the food into big bowls.
So say Cornell University professor Brian Wansink, PhD, and colleagues in an upcoming issue of the American Journal of Preventive Medicine.
"Those interested in losing weight should use smaller bowls and spoons, while those needing to gain weight -- such as the undernourished or aged -- could be encouraged to use larger ones," write the researchers.
Wansink's findings come from an ice cream social with a hidden agenda. The guest list included 85 faculty members, graduate students, and staff members from a large Midwestern university's nutrition department.
Dishing on Portion Size
Wansink and colleagues randomly gave their guests smaller or larger bowls and smaller or larger ice cream scoops. They didn't draw attention to the bowls or utensils.
How big were the bowls and spoons? The smaller bowls could hold up to 17 ounces; the larger bowls were twice as big. The smaller scoops could hold up to 2 ounces; the larger scoop could hold 3 ounces.
The guests helped themselves to the ice cream. Then the party briefly became more scientific than social.
Partygoers were asked to eyeball their bowl and guess how much ice cream it contained. Then the researchers weighed the ice cream before anyone took even a tiny taste.
Room for More
The big-bowl group served themselves 31% more ounces of ice cream than those who had gotten the small bowls (6.25 ounces with the bigger bowl and 4.77 ounces with the smaller bowl). But they didn't realize it, the study shows.
"Even when nutrition experts were given a larger bowl, they served themselves 31% more without being aware of it," write Wansink and colleagues.
People also tended to serve themselves more ice cream with the bigger scoop than with the smaller scoop, but that might have been due to chance, the study shows. The biggest portions came when big scoops doled ice cream into big bowls.
Nutritionist or not, people tend to suit their servings to their bowl, note Wansink and colleagues. The researchers recommend picking your plates, dishes, and utensils accordingly.