Expected satiety
{{short description|Anticipated relief from hunger provided by a food}}
Expected satiety is the amount of relief from hunger that is expected from a particular food. It is closely associated with expected satiation which refers to the immediate fullness (post meal) that a food is expected to generate.
Scientists have discovered that foods differ considerably in their expected satiety. One estimate in the United Kingdom suggested that there may be a six-fold difference in foods commonly consumed there, when they are compared calorie for calorie.{{cite journal
| last1 = Brunstrom
| first1 = J.M.
| title = Measuring 'expected satiety' in a range of common foods using a method of constant stimuli.
| journal = Appetite
| date = 2008
| volume = 51
| issue = 3
| pages = 604–614
| doi=10.1016/j.appet.2008.04.017
| pmid=18547677
| s2cid = 24318905
}} This range of variation is important because expected satiety is thought to be a good predictor of food choice and an excellent predictor of self-selected portion sizes.{{cite journal
| last1 = Brunstrom
| first1 = J.M.
| title = How many calories are on our plate? Expected fullness, not liking, determines meal-size selection
| journal = Obesity
| date = 2012
| volume = 17
| issue = 10
| pages = 1884–1890
| doi = 10.1038/oby.2009.201
| pmid=19543204
| doi-access= free
}} Specifically, foods that have high expected satiety and high expected satiation tend to be selected in smaller portions (fewer calories). Therefore, they may be especially suited to diets that are designed to reduce energy intake.
Some researchers also suggest that expected satiety is an important mediator of energy intake.{{cite journal
| last1 = Brunstrom
| first1 = J.M.
| title = Mind over platter: pre-meal planning and the control of meal size in humans
| journal = International Journal of Obesity
| date = 2014
| volume = 38
| issue = Suppl 1
| pages = S9–12
| doi = 10.1038/ijo.2014.83
| pmid = 25033963
| pmc= 4105578
| last1 = Forde
| first1 = C.G.
| title = Expected Satiety: Application to weight management and understanding energy selection in humans
| journal = Current Obesity Reports
| date = 2015
| doi = 10.1007/s13679-015-0144-0
| pmid = 26627096
| volume=4
| issue = 1
| pages=131–140
| pmc= 4881812
}} They argue that within-meal events (immediate post-ingestive feedback, e.g., gastric stretch) play a relatively minor role and that meal size is largely determined by decisions about portion size, before a meal begins. Consistent with this proposition, observational studies show that 'plate cleaning' is extremely common,{{cite journal
| last1 = Wansink
| first1 = B.
| title = The clean plate club: about 92% of self-served food is eaten
| journal = International Journal of Obesity
| date = 2014
| doi = 10.1038/ijo.2014.104
| pmid = 24946909
| volume=39
| issue = 2
| pages=371–374
| doi-access= free
}} that humans tend to plan their meal size in advance, and that ad libitum eating is relatively rare.{{cite journal
| last1 = Wilkinson
| first1 = L.L.
| title = Computer-based assessments of expected satiety predict behavioural measures of portion-size selection and food intake
| journal = Appetite
| date = 2012
| volume = 59
| issue = 3
| pages = 933–938
| doi=10.1016/j.appet.2012.09.007
| pmid = 22989621
| s2cid = 11942486
| url = https://cronfa.swan.ac.uk/Record/cronfa21022
| last1 = Fay
| first1 = S.
| title = What determines real-world meal size? Evidence for pre-meal planning
| journal = Appetite
| date = 2011
| volume = 56
| issue = 2
| pages = 284–289
| doi=10.1016/j.appet.2011.01.006
| pmid=21232568
| s2cid = 32092114
| url = https://eprints.qut.edu.au/46762/2/46762.pdf
}}
Measurement
Early approaches relied on rating scales.{{cite journal
| last1 = Green
| first1 = S.M.
| title = Subjective and objective indices of the satiating effect of foods. Can people predict how filling a food will be?
| journal = European Journal of Clinical Nutrition
| date = 1996
| volume = 50
| issue = 12
| pages = 798–806
| pmid = 8968700
| last1 = de Graaf
| first1 = C.
| title = Beliefs about the satiating effect of bread with spread varying in macronutrient content
| journal = Appetite
| date = 1992
| volume = 18
| issue = 2
| pages = 121–128
| doi=10.1016/0195-6663(92)90189-d
| pmid = 1319130
| s2cid = 12187141
}} More recently, techniques have been developed that quantify expectations very precisely by comparing foods directly on a calorie-for-calorie basis. The first of these used a classical psychophysical approach based on a 'method of constant stimuli'.{{cite journal
| last1 = Brunstrom
| first1 = J.M.
| title = Measuring 'expected satiety' in a range of common foods using a method of constant stimuli
| journal = Appetite
| date = 2008
| volume = 51
| issue = 3
| pages = 604–614
| doi=10.1016/j.appet.2008.04.017
| pmid=18547677
| s2cid = 24318905
}} Participants are shown a fixed 'standard' portion of food and this is compared against a different 'comparison' food. Over a series of trials the size of the comparison food is manipulated and participants are asked to pick the food that is expected to deliver greater satiety. At the end of the task a measure of 'expected satiety' is calculated. This relates to the number of calories of the comparison food that would be expected to deliver the same satiety as the fixed standard. A conceptually similar alternative is to use a 'method of adjustment'. Participants are shown a picture of a standard food next to a picture of a comparison food. Using specialist software, participants change the size of the comparison portion using keyboard responses.{{cite journal
| last1 = Brunstrom
| first1 = J.M.
| title = How many calories are on our plate? Expected fullness, not liking, determines meal-size selection
| journal = Obesity
| date = 2009
| volume = 17
| issue = 10
| pages = 1884–1890
| doi=10.1038/oby.2009.201
| pmid=19543204
| doi-access= free
}} Pictures are loaded with sufficient speed that the change in the comparison becomes 'animated.' Participants are told to match the comparison food until both are expected to deliver the same satiety. If the same standard is used then the expected satiety of different foods can be quantified and compared directly.
Determinants
Expectations about the post-ingestive effects of a food are learned over time.{{cite journal
| last1 = Brunstrom
| first1 = J.M.
| title = Conditioning 'fullness expectations' in a novel dessert
| journal = Appetite
| date = 2009
| volume = 52
| issue = 3
| pages = 780–783
| doi = 10.1016/j.appet.2009.02.009
| pmid = 19501781
| s2cid = 31078385
| url = https://cronfa.swan.ac.uk/Record/cronfa21024
}} In particular, it would appear that the expected satiety and expected satiation of foods increases as they become familiar.{{cite journal
| last1 = Irvine
| first1 = M.
| title = Increased familiarity with eating a food to fullness underlies increased expected satiety
| journal = Appetite
| date = 2012
| volume = 61
| issue = 13–18
| doi=10.1016/j.appet.2012.10.011
| pmid = 23092755
| pages=13–18
| s2cid = 35976185
| last1 = Hardman
| first1 = C.
| title = Children's familiarity with snack foods changes expectations about fullness
| journal = American Journal of Clinical Nutrition
| date = 2011
| volume = 94
| issue = 5
| pages = 1196–201
| doi=10.3945/ajcn.111.016873
| pmid=21918214
| doi-access= free
| last1 = Brunstrom
| first1 = J.M.
| title = Familiarity changes expectations about fullness
| journal = Appetite
| date = 2010
| volume = 54
| issue = 3
| pages = 587–90
| doi=10.1016/j.appet.2010.01.015
| pmid = 20138942
| s2cid = 33559237
}}
Expectations are also thought to be governed by the orosensory characteristics of food. Even subtle changes to the flavor or texture of food can have a marked effect.{{cite journal
| last1 = Hogenkamp
| first1 = P.S.
| title = Expected satiation after repeated consumption of low- or high-energy-dense soup
| journal = British Journal of Nutrition
| date = 2012
| volume = 108
| issue = 1
| pages = 182–190
| doi=10.1017/s0007114511005344
| pmid = 22017801
| doi-access= free
| last1 = McCrickerd
| first1 = K.
| title = Subtle changes in the flavour and texture of a drink enhance expectations of satiety
| journal = Flavour Sci Recent Dev
| date = 2012
| volume = 1
| issue = 20
| pages = 1–11
| doi=10.1186/2044-7248-1-20
| doi-access= free
}} Expected satiation may be higher in foods that have a higher protein content, and in those that require more chewing and that are eaten slowly.{{cite journal
| last1 = Forde
| first1 = C.G.
| title = Oral processing characteristics of solid savoury meal components, and relationship with food composition, sensory attributes and expected satiation
| journal = Appetite
| date = 2013
| volume = 60
| issue = 1
| pages = 208–219
| doi=10.1016/j.appet.2012.09.015
| pmid = 23017464
| s2cid = 9958239
| last1 = Ferriday
| first1 = D.
| title = Exploring relationships between expected satiation, eating topography and actual satiety across a range of meals
| journal = Appetite
| date = 2013
| volume = 71
| issue = 1
| pages = 474
| doi=10.1016/j.appet.2013.06.021
| s2cid = 54408143
}} Remarkably, it also appears that the expected satiety and expected satiation of foods is influenced by their perceived weight.{{cite journal
| last1 = Piqueras-Fiszman
| first1 = B.
| title = The weight of the container influences expected satiety, perceived density, and subsequent expected fullness
| journal = Appetite
| date = 2012
| volume = 58
| issue = 2
| pages = 559–562
| doi=10.1016/j.appet.2011.12.021
| pmid = 22245134
| s2cid = 3275288
}}
Effect on appetite
The effects of expected satiety and expected satiation appear to extend beyond meal planning. Several studies show that these expectations also influence the hunger (physiology) and fullness that is experienced after a meal has been consumed.{{cite journal
| last1 = Brunstrom
| first1 = J.M.
| title = 'Expected satiety' changes hunger and fullness in the inter-meal interval
| journal = Appetite
| date = 2011
| volume = 56
| issue = 2
| pages = 310–5
| doi=10.1016/j.appet.2011.01.002
| pmid = 21219951
| s2cid = 32342690
}} Product labelling and branding is likely to modify expected satiety.{{cite journal
| last1 = Fay
| first1 = S.H.
| title = Product labelling can confer sustained increases in expected and actual satiety
| journal = Appetite
| date = 2011
| volume = 57
| issue = 2
| pages = 557
| doi=10.1016/j.appet.2011.05.069
| s2cid = 54231213
| url = https://eprints.qut.edu.au/46772/4/46772.pdf
}} Therefore, this kind of information has the potential to influence appetite directly. Together, these observations are consistent with emerging evidence that implicates hippocampal-dependent memory mechanisms in behavioural responses to food.{{cite journal
| last1 = Brunstrom
| first1 = J.M.
| title = Episodic memory and appetite regulation in humans
| journal = PLOS ONE
| date = 2012
| volume = 7
| issue = 12
| doi = 10.1371/journal.pone.0050707
| pages=e50707
| pmid=23227200
| pmc=3515570
| doi-access = free
| last1 = Higgs
| first1 = S.
| title = Memory for recent eating and its influence on subsequent food intake
| journal = Appetite
| date = 2002
| volume = 39
| issue = 2
| pages = 159–66
| doi=10.1006/appe.2002.0500
| pmid = 12354684
| s2cid = 22842724
| last1 = Kanoski
| first1 = S.E.
| title = Western diet consumption and cognitive impairment: Links to hippocampal dysfunction and obesity
| journal = Physiology and Behavior
| date = 2011
| volume = 103
| issue = 1
| pages = 59–68
| doi = 10.1016/j.physbeh.2010.12.003
| pmid=21167850
| pmc=3056912
}}
Notes
Recent reviews{{Cite journal|last1=Fiszman|first1=Susana|last2=Tarrega|first2=Amparo|date=2017|title=Expectations of food satiation and satiety reviewed with special focus on food properties|journal=Food & Function|language=en|volume=8|issue=8|pages=2686–2697|doi=10.1039/C7FO00307B|pmid=28686245|issn=2042-6496}} highlight opportunities to reformulate commercial food products to increase their expected satiety and expected satiation.