HUNGER.2 +portion sizes Flashcards
THE SATIETY CASADE
Blundell 2010-
expected satiety and expected satiation
The extent to which a food/portion will elicit satiation and satiety
can be predicted before a meal begins.
* Expected satiety: the perception, before consumption, of the
ability of a food to stave off hunger.
* Expected satiation: the perception, before consumption, of the
ability of a food to deliver fullness.
* Experimental evidence to suggest that expected satiation/satiety of
foods can strongly influence pre-meal decisions about food and
portion selection (e.g., Brunstrom, Shakeshaft & Alexander, 2008).
- These expectations can be learned. The more familiar a food is
to an individual, the more filling it is expected to be. - Expected satiety/satiation is influenced by the perceived volume of the food. The larger the perceived volume, the more filling it is expected to be.
- Exposure to different varieties of food reduces expected satiety/satiation.
- Energy density is negatively correlated with expected
satiation/satiety. The higher a food’s energy density, the less filling it is perceived to be.
Routine decisions and automatic processing can lead to passive overconsumption of foods.
Portion sizes!
QUESTION- if we give people more food do they eat more?
previous- Van ittersam and watkins 2013- Geier, rozin, doros 2006- unit bias
Rolls, Morris & Roe (2002).
▫ +30% more energy for largest portions (1000g) compared- (people felt the same amount of fullness)
to the smallest (500g)
* Rolls et al., (2004).
▫ Replicated with sandwiches
▫ Gender differences- more in males
▫ Similar ratings of fullness
* Meta-analysis of 65 studies found that doubling the
portion served to individuals, increases food intake by
~35% (Zlatevska, Dubelaar & Holden, 2014)
studies on plate cleaning
plate cleaning/ leftovers- different between normal weight and overweight individuals- Brownell et al., 1979- overweight women left less food on their plate (overweight are worse at regulating their intake?- more effected by external cue such as unit bias)
why larger portion sizes mean we eat more?
- Larger portions:
▫ Encourage consumption past satiation
▫ Indicates socially appropriate amount to consume
▫ Adjust biological signals and cognitive perceptions over time about what portion
elicits satiety
▫ Primal instincts to consume as much food as possible when available. - Ability to regulate food intake changes as we age - children <3 better at regulating
intake and less affected by external cues - Experimental evidence indicates sig. impact on food intake in the short term; Similar
effects in naturalistic settings
rolls 2006; vermeer 2011 - Longitudinally - Limited adjustment for increases in intake (e.g., )
▫ The upper end ‘set point’ intervention to reduce intake is much weaker than the
lower end intervention to increase intake.
individual differences in portion size
Cunningham et al., 2023- looked at eating rate
Cunningham et al., (2023).
* Repeated measures over four weeks.
* Macaroni cheese served in 400g to 700g
portion sizes (increases by 100g)
* N = 44 (29 female)
* Explored how elements of eating microstructure (e.g., meal duration, bite count, mean bite size, and mean eating rate) were linked to portion size increases.
Faster eating rate and larger bite sizes were related to greater food consumption, but did not moderate the portion size effect (i.e. associated with greater consumption at all portion sizes)
so those who eat faster and alrger bites eat more BUT this was not controlled by portion sizes- portion sizes still effected consumption alone. All portion size eating faster and larger bites= more consumption
the portion size was not moderated by eating structure
portion size effect pt2
Hetherington and Blundell 2018-
Looked at portion sizes of high energy dense foods (HEF). Portion size effect has been studied lots, showing if we increase protion sizes consumption also increases.
An obvious solution to the PSE is to ‘downsize’ HED meal items and snacks, but whether this strategy is acceptable or feasible is not clear. In adults, the effects of downsizing are mixed and for children and adolescents, as yet unclear. The contention is that for those who are still learning about social norms and appropriate portions, there remains the potential to counter the PSE through downsizing strategies.
To date, efforts to provide small portions of foods or beverages to reduce intake have produced mixed results in adults. This may be due to awareness of smaller than usual portions, and so consumers feel hungry or that they have missed out on their typical amount. It could be that small size packaging is attractive, portable and convenient but might inadvertently increase consumption. However, in children, there is the opportunity to shape expectations about appropriate portions—namely ‘me-size’ amounts (e.g. UK government Change4Life campaign http://change4lifewales.org.uk/families/mesize/?lang=en). In addition, for adolescents, who are also establishing dietary habits and food choices, there is the chance to intervene to encourage downsized portions. It is imperative to investigate the impact of downsizing and to provide an evidence base for parents to adjust children’s portions of meal items and snacks to suit their needs and appropriate to their size.
way more research needed- long term effects of portion size effect still less understood but portion size with energy dense food over long period of time must lead to weigth gain (WHO 2014)
unit bias 2
Kerameas et al., 2015:
The “unit bias” has been proposed as an explanation for the portion-size effect; people consider a single unit to be an appropriate amount to eat and thus eat more when served a larger unit than when served a smaller unit. We suggest that the unit bias might be better characterized as a “segmentation effect,” such that people eat less when a unit of food is separated into smaller subunits, but may eat more than a single unit. Furthermore, we suggest that portion-size effects should be independent of this segmentation effect. Method: In Study 1, female participants (n = 87) were served either a small or large portion of food that was either presented in the form of a single unit or multiple individually wrapped units. In Study 2, female participants (n = 42) were served a fixed portion of food that was either presented in the form of a single unit or multiple units presented on separate plates. Results: Across both studies, there was no evidence that participants prefer to eat a single unit. Participants served multiple smaller units did eat less than did participants served a single larger unit, even when the overall portion size was the same, but the amount eaten was consistently more than a single unit. Furthermore, perceived norms of appropriate intake mediated the effect of unit number on food intake. Conclusions: These findings suggest that a segmentation effect, rather than a unit bias, is driving people’s food intake, with implications for designing interventions aimed at reducing excessive food intake.
The study shows that breaking food into smaller pieces (segmentation) is more effective at controlling how much people eat than the idea of “unit bias,” which suggests people stop after eating one unit. Even if people eat more than one small piece, they tend to eat less overall compared to when food is served as one big piece. This means how food is presented—like dividing it into smaller portions—can help reduce overeating better than just focusing on the size of the portion
