A study in September's Journal of the American Dietetic Association serves as a portion-size time capsule.
Jaime Schwartz, MS, RD, worked on the study as a graduate student at Rutgers University. She's now in the food and wellness group of a New York public relations firm.
At the study's heart is "portion distortion," especially when big servings start to look normal.
Serving sizes have boomed at restaurants and in many packaged foods in recent years.
And people tend to eat more when they get big servings. So if whopping portions become the norm, people might unwittingly overeat.
"Our society wants the 'bang for our buck' and when portions are served to us that we think are small we feel short-changed," Schwartz says, in a Rutgers news release.
"But we need to start 'undistorting' what we perceive to be a typical portion and begin to listen to our stomachs, not our eyes, to determine when to put the fork down," Schwartz says.
Schwartz hosted 177 mostly female college students at breakfast, lunch, or dinner buffets. She asked the students to serve themselves what they considered a typical portion of each item.
On the menu:
- Breakfast. Cornflakes, sugar, milk, orange juice, toast, butter, and jelly.
- Lunch & dinner. Tuna salad, bread, tossed salad, salad dressing, fruit salad, and soda (diet or regular).
Each student went through the buffet line alone. They had their choice of different sizes of plates, bowls, cups, and utensils.
The researchers weighed the serving bowls before and after the students served themselves in order to gauge the students' serving size -- secretly weighing the bowls out of the students' sight.
The students' typical serving sizes differed from an identical study from 1984:
- Cornflakes servings were up nearly 20%.
- Servings of milk poured onto cornflakes rose by almost 30%.
- Orange juice servings grew by about 45%.
- Fruit salad servings increased by a third.
The items were all served in a cup or bowl. The study doesn't show whether the students chose big cups and bowls, which might have tempted them to dish out bigger portions.
The students didn't supersize portions across the board. They cut back on some items.
Compared with the 1984 study, these students served 21% less salad dressing and 13% less tossed salad. They also poured nearly a third less sugar on their cornflakes.
Those shrinking portions may reflect awareness about limiting fat (in salad dressing) and sugar, the researchers note.
However, the study doesn't show what shaped the students' views on portion sizes in either era. It's also not known if other people share the students' views on typical portion size.
SOURCES: Schwartz, J. Journal of the American Dietetic Association, September 2006. News release, Rutgers, the State University of New Jersey. Jaime Schwartz, MS, RD, senior account executive, Food and Wellness Group, Ketchum.
By Miranda Hitti
Reviewed by Louise Chang