Food Portions

Background and objectives: Recent studies have emphasized that a size-contrast illusion leads unknowingly consumers to serve and eat more food when using larger dinner plates and serving spoons. Such a size-contrast illusion would not, however, be operating when one serves from a common serving bowl. Exploring if and how serving bowls might bias intake offers the potential to uncover other mechanisms through which environmental cues influence behavior.
Methods: In this between-subjects experiment, eighty six participants served themselves pasta either from a large serving bowl (about 6.9 liter capacity) or from a medium-sized serving bowl (about 3.8 liter capacity). After eating their fill, they completed a questionnaire, and their remaining pasta was weighted.
Results: When given a larger serving bowl, diners served 78% more pasta (425.9 versus 283.9, p< 0.001), even though they did not rate the food as any tastier, or otherwise notable (all ps>0.24). In contrast to studies involving large-sized plates and spoons, people serving from larger bowls appeared to realize they served more and rated themselves as marginally more full afterwards.
Discussion: These findings again highlight the role that external cues play in food consumption and show the importance of considering the size of serving bowls containing multiple portions in relation to nutrition education on weight loss and maintenance. Instead of a size-contrast illusion driving the results, a different mechanism, such as consumption norms may operate on such occasions.

The average calorie increase in 18 classic American recipes has increased 35.2 percent per serving over the past 70 years. Part of this is due to the use of more caloric ingredients and part to serving sizes that showed small increases in the late 1940s and early 1960s, but showed a 33.2% increase since1996. 
The calories and portion sizes of classic recipes may reflect prevailing tastes and norms.  Yet they may also establish or reinforce exaggerated norms in others, such as new families.  Although this study is largely descriptive, it does imply a prescriptive recommendation for families.  The serving size and calorie composition of classic recipes need to be downsized to counteract growing waistlines.

People eat meals rather than nutrients or food groups.  Plate size may influence meal size, meal composition, and food type.  To examine effects of plate size on meals, we developed a method we label plate mapping. A quasi-experimental study asked university students to accurately draw what they would like to eat for dinner on either a 9" or 11" paper plate. Coding plate drawings for total meal size revealed that students drew an average of 26% more food on larger plates. When plates were coded for meal composition we found that the biggest three food portions drawn by students were bigger on 11” plates, with 70% of the overall difference in food area occurring in the biggest food.  Participants drew bigger portions of vegetables on larger plates, while other food types showed little change in mean size.  Gender moderated plate sensitivity for food types: women drew 36% bigger vegetable portions than men on larger plates. Smaller plates may lead to smaller meal sizes, but plate size may differentially influence composition of meals for men and women.  These findings suggest plate mapping can be used to reflect meal conceptualizations and assess sensitivity to plate size.

Objective: Because younger children lack the motor skills required to serve themselves without spilling, adults often ask children how much they would like to eat and then serve the requested amount onto bowls. Previous research shows that larger bowls biases adults towards serving themselves larger portions. We examine if larger bowls biases children towards requesting ore food from the adults who serve them.
Study Design: Study 1 was a between-subject design involving 69 pre-schoolers who were randomized to receive either a small (8 oz) or large (16 oz) cereal bowl and were asked to tell researchers how much cereal they wanted for a morning snack. Study 2 was a within-subject design involving 18 elementary school age children at a summer camp who were given a small (8 oz) cereal bowl on one day and a large (16 oz) cereal bowl on another day and asked by a cafeteria server how much cereal and milk they wanted for breakfast.
Methods: Hidden scales measured how much cereal and milk were served, consumed, and wasted. BMI levels were obtained at the study.
Results: Study 1 indicated that younger children requested almost twice cereal to eat when presented with a larger bowl. Study 2 shows that older children consumed 52% more and wasted 26% more when served with a larger bowl.
Conclusion: An immediate step to reducing overeating would be for parents and adult caregivers to use smaller bowls when serving food to children.

Does the size of a plate influence the serving of all items equally, or does it influence the serving of some foods – such as meat versus vegetables – differently? To examine this question, we used the new method of plate mapping, where people drew a meal on a paper plate to examine sensitivity to small versus large three-compartment divided plates in portion size and meal composition in a sample of 109 university students. The total drawn meal area was 37% bigger on large plates than small plates, which showed that the portion of plate coverage did not differ by plate size. Men and women drew bigger vegetable portions and men drew bigger meat portions on large plates when compared to small plates. These results suggest that men and women are differentially sensitive to plate size for overall meal size and for meal composition. Implications for decreasing portion size and improving meal balance are that plate size may influence portion size and change the proportions of foods served.

The evaluation of food intake is critical and underreporting is frequent. The aim was to develop an indirect statistical method of the total energy intake estimation based on gender, weight and the number of portions. Energy intake prediction was developed and evaluated for validity us-ing energy expenditure. Volunteers with various BMIs were recruited and assigned either in the train or the test sample. The mean energy provided by a portion was evaluated by linear regres-sion models from the train sample. The absolute values of the error between the energy intake estimation and the energy expenditure measurement were calculated for each volunteer, by subgroup and for the whole group. The performance of the models was determined using the validation dataset. As the number of portions is the only variable used in the model, the error was 26.5%. After adding body weight in the model, the error decreased to 8.8% and 10.8% for the normal-weight women and men, and 11.7% and 12.8% for the overweight volunteers. The find-ings indicate that a statistical approach and knowledge of the usual number of portions and body weight is effective and sufficient to obtain a precise evaluation of energy intake after a simple and brief enquiry

Does the size of a plate influence the serving of all items equally, or does it influence the serving of some foods - such as meat versus vegetables - differently? To examine this question, we used the new method of plate mapping, where people drew a meal on a paper plate to examine sensitivity to small versus large three-compartment divided plates in portion size and meal composition in a sample of 109 university students. The total drawn meal area was 37% bigger on large plates than small plates, which showed that the portion of plate coverage did not differ by plate size. Men and women drew bigger vegetable portions and men drew bigger meat portions on large plates when compared to small plates. These results suggest that men and women are differentially sensitive to plate size for overall meal size and for meal composition. Implications for decreasing portion size and improving meal balance are that plate size may influence portion size and change the proportions of foods served.