Melbourne: People given large servings of food eat more than those given smaller servings, even after they have been taught about the impact of portion size on consumption, a new study has found.
The study, published in the Journal of Health Psychology, highlights the need to find new ways to reduce the effect of portion size on overeating. "Studies have consistently shown that increases in portion sizes for a wide range of foods and beverages result in increased energy intake. And the impact is not affected by factors such as hunger or the taste of the food," said Dr Lenny Vartanian, a senior lecturer in the University of New South Wales School of Psychology and an author of the paper.
The team, including researchers from the University of Toronto in Canada, found that learning how to engage in mindful - rather than mindless - eating also did not decrease food intake by a significant amount in those given large servings.
In the study, 96 women were served either a 350 gram portion of macaroni pasta with tomato sauce for lunch, or a 600 gram portion.
Those in the education group were given a brochure about how external factors, such as mood, advertising, portion size, and social and cultural influences can contribute to overeating, and then asked to write about how these factors had influenced their food intake in the past.
Those in the mindfulness group were also taught how to focus on the internal sensations such as the taste of food and feelings of hunger and satiety, before they were offered the pasta.
"Neither of these brief exercises reduced the effects of portion size. Overall, participants in the larger portion group consumed about a third more pasta - 69 grams - than those in the smaller portion group," Vartanian said.
This difference amounts to about 87 kilocalories of extra energy.