Therapeutics, University of Dundee, Ninewells Hospital and Medical School,. Dundee, DD1 9SY. 2 Orthopaedic & Trauma Surgery, Division of Surgery and ...
Final Technical Report to the Food Standards Agency
CALCULATION AND COLLATION OF TYPICAL FOOD PORTION SIZES FOR ADULTS AGED 19-64 AND OLDER PEOPLE AGED 65 AND OVER
Project number: N08026
Authors WENDY L. WRIEDEN1 KAREN L. BARTON1
Advised By: LYNDA COCHRANE2 ASHLEY J. ADAMSON3
1
Centre for Public Health Nutrition Research, Division of Medicine and
Therapeutics, University of Dundee, Ninewells Hospital and Medical School, Dundee, DD1 9SY 2
Orthopaedic & Trauma Surgery, Division of Surgery and Oncology, University
of Dundee, Ninewells Hospital and Medical School, Dundee, DD1 9SY 3
Human Nutrition Research Centre, University of Newcastle, Newcastle, NE2
4HH Commenced 2nd August 2004 Completed 28th February 2006
Report 28th February 2006
1
Contents 1. Executive Summary
4
1.1 Aims and Objectives 4 1.2 Approach
4
1.2.1 Calculation of Typical Portion Weights 1.2.2 Testing of Typical Portion Weights
4
5
1.2.2 Manufactured and Catered Portion Weights 5 1.3 Key Findings 5 1.4 Technical Evaluation and Interpretation 6 2. Glossary of Terms and Abbreviations 7 3. Introduction
9
4. Aims and Objectives
11
5. Experimental Procedures 5.1 Overview
12
5.2 Methods
12
12
5.2.1 Calculation of Typical Portion Weights 5.2.2 Testing of Typical Portion Weights
12
13
5.2.3 Manufactured and Catered Portion Weights 14 6. Results
15
6.1 Calculated Portion Weights 15 6.2 Testing of Typical Portion weights 16 6.2 Manufactured foods portion weights (as item weight or weight served) 6.2.2 Manufactured and Supermarket Foods
17
6.2.3 Fast Food Outlet and Restaurant Chain Data 7. Discussion and Conclusions 2
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17
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8. Acknowledgements 9. References
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21
Table 1: Calculated Portion Weights
Error! Bookmark not defined.
List of appendices
20
3
1. Executive Summary 1.1 Aims and Objectives The overall aim of the study was to produce a set of typical food portion weights for younger and older adults.
The individual objectives were: To extract food portion information from recent dietary surveys of adults (National Diet and Nutrition Survey (NDNS) of adults aged 19-64 years and people aged 65 years and over). To collate current information on portion sizes of packaged foods and fast foods commonly eaten. To produce a list of typical food portion sizes for each age range. To trial the use of typical food portion weights in dietary surveys. To produce list of portion sizes for foods for adults and older people.
1.2 Approach 1.2.1 Calculation of Typical Portion Weights NDNS databases were obtained and food portion data was extracted. Similar foods (e.g. Cornflake type cereals) were grouped and re-coded in order to facilitate processing. A comprehensive analysis of the factors affecting portion size, including age, gender, illness, time of day and (in the elderly) free-living or institutional was then carried out. Age was grouped by widely used categories (19-34, 35-49, 5064, 65-74 and 75+). The results of the analysis showed that it was necessary to restrict the number of foods for which portion size is recorded for the gender and age groups as some numbers were insufficient to determine a reliable estimate of portion size.
The data were highly variable, with a significant
number of extreme values. These could not be investigated, nor could they be deemed as clearly erroneous.
For this reason median portion sizes were
calculated and non-parametric methods were used to look at the factors that caused a significant difference in portion weights. Where these differences occurred and numbers were sufficient individual medians were calculated for age group and / or gender. In addition where there were significant differences 4
in portion weight between free-living and institutionalised subjects over 65 year olds, a separate portion weight was estimated.
1.2.2 Testing of Typical Portion Weights To test the use of the calculated portion sizes, weighed food diaries of Scottish mothers aged 25-46 years (n 35) collected 1996-1997 and men and women aged 40-74 (n 64) collected 1999-2002, were reanalysed for energy and nutrients using the actual and calculated weights (medians) for each food. The methods of Bland and Altman were used to investigate the agreement between nutrient intakes calculated from actual and calculated portion weights.
1.2.2 Manufactured and Catered Portion Weights A range of companies including food manufacturers, supermarkets and fast food/ restaurant chains were contacted and information on portion sizes obtained.
Supermarkets were visited and an extensive search of websites
carried out to obtain further information. 1.3 Key Findings In total, information
on
3411
individuals,
2999
free-living
and
412
institutionalised, was available from the two surveys (age and gender data not available for 94 individuals in the 19-64 age group).
Similar foods were
grouped into 751 food groupings. Some of the food groupings with larger numbers were broken down according to mode of consumption upon further examination e.g. milk in tea/coffee, in cereal, as a drink etc. No cut-off points for inclusion were used and all similar foods regardless of the number of times they had been consumed were included in the food groupings. Those food groupings with 10 or more consumers (in either of the 19-64 or 65+ NDNS databases) were included in the list of foods for which portion sizes were calculated (food groupings with less than 10 consumers in either NDNS database were coded as insufficient numbers). Mean daily energy and nutrient intakes were calculated from the food diaries using calculated median portion weights (using an age/gender specific portion weight where available). Differences between the energy and nutrient intakes 5
from the actual and calculated portion weights were small for females but considerably larger for males but most individual values lay within 2 standard deviations of the mean difference.
Portion weights collected for manufactured foods, included bread, biscuits, ready meals, burgers, sausages, meat pies, yogurts, savoury snacks, confectionery and soft drinks. 1.4 Technical Evaluation and Interpretation Other work has found that standard portion sizes gave lower mean estimates of energy and nutrient intakes than reported portion sizes, with greater differences in men than in women. This was despite a much larger sample size than in the current project. A suggested method was given to adjust portion sizes which could be further explored.
It is recommended that further work is carried out to address any anomalies due to small number of diaries being tested and to cover more of the foods for which weights have been calculated. The calculated portion sizes, together with the extensive list of manufactured and catered portion sizes will be useful in assessing the diets of groups of adults. In addition they can be used as a guide for researchers devising dietary assessment tools for adults.
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2. Glossary of Terms and Abbreviations Age Group 1
19-34 years
Age Group 2
35-49 years
Age Group 3
50-64 years
Age Group 4
64 -75 years
Age Group 5
75+ years
Bland Altman plot A method, based on graphical techniques and simple calculations, to compare a new measurement technique with an established method. In this case the use of calculated typical portion sizes is compared with the use of weighed portion sizes in dietary analysis
CPHNR
Centre for Public Health Nutrition Research
g
gram
kJ
kilojoule = 1000 joules A unit used to measure the energy value of a food
NDNS Nutrient Databank A specially adapted nutrient databank used in the NDNS containing nutritional information on over 7000 foods
Mean
Median
The average value
The median of a distribution divides it in two equal parts, such that
half the cases in the distribution fall, or have a value, above the median, and the other half fall, or have a value below the median
mg
milligram = 1/1000 of a gram
n
number
7
NDNS
National Diet and Nutrition Survey – a major component of the
Food Standards Agency’s Dietary Survey Programme providing crosssectional information on the dietary habits and nutritional status of nationally representative samples of the British population
NSP
Non-starch polysaccharide
SD
Standard deviation
µg
microgram = 1/1000000 of a gram
UK
United Kingdom
8
3. Introduction The energy and nutrient intake of groups of individuals can be estimated using the published Food Portion Sizes1 to assign weights to data collected from 24 hour recalls, diet histories, food diaries and food frequency questionnaires. Food portion weights have been estimated from weighed dietary surveys and as such are based on average weights of a large variety of foods eaten by adults. Although not advised for use in assessing individual diets, they are useful for pooled data of normal healthy individuals. Current published food portion sizes were calculated using the data from the 1986-1987 Dietary and Nutritional Survey of British Adults2 but since this survey many new food products have been introduced. The technical report3 to the latest British National Diet and Nutrition Survey of adults aged 19-64 years (2000-2001)4 describes how changes in lifestyle (including greater numbers of people travelling abroad and increased multiculturalism) since the 1986-1987 survey has led to a greater variety of foods being available in the UK. There is also evidence from the USA that portion sizes for specific foods e.g. soft drinks, hamburgers, and French fries have increased over the last twenty years5,6. In addition there are no UK portion sizes for older people and given the reduced energy needs of the older population7 it would be expected that portion sizes may be smaller. In conjunction with published food composition tables8 or nutritional information from food labels, surveys using standard portion weights (e.g. 24 hour recalls and food frequency questionnaires) have been shown to provide information that is similar to that collected from the more costly and timeconsuming weighed food record method9 or estimated food records10. However, Welten and colleagues10 comment that the accuracy of standard food portions may be doubtful and in their own investigation found that the USDA serving sizes used as standard portion sizes provided significantly lower estimates of energy and nutrient values when compared with reported portion size (estimated by the individual). In the UK there are two publications which provide data on food portion sizes, Food Portion Sizes, recently reissued by the Food Standards Agency1 and A Photographic Atlas of Food 9
Portion Sizes11 (which provides photographs of a range of food portion sizes based on the 5th to the 95th percentile of the range of foods from the 1986-1987 adult NDNS2. More recent, but unpublished work, showed that use of average food portion sizes calculated from the latest National Diet and Nutrition Surveys of children12,13, gave age group means for energy and nutrient values that were not significantly different from those calculated using weighed intakes14. Latest studies of the dietary intake of adults in the National Diet and Nutrition Surveys have collected weighed intake data from nationally representative samples of 19-64 year olds and people aged 65 and over15. Thus there is a large database from which to estimate the average portion sizes eaten by adults of different ages. Additionally several studies have been carried out in the University of Dundee, which have collected weighed food diaries from adults. These can be used to corroborate portion weights calculated from the NDNS surveys. Portion weights of manufactured products are available from food manufacturers, supermarkets and fast food/ restaurant chains, and the list available from the Centre for Public Health Nutrition Research project on children’s food portions can be updated and extended. Collation of manufacturer’s portion weights and extraction of data from the large national surveys will provide an updated set of standard portion sizes to be produced for use in dietary surveys of adults. This will enable surveys to be carried out without the need for weighed food diaries and should thus improve compliance. It should also enable realistic portion sizes to be assigned in surveys carried out using food frequency questionnaires. Nevertheless it must be pointed out that the use of typical portion weights are limited and should not be used to provide a reliable estimate of the diet of individuals.
10
4. Aims and Objectives The overall aim of the study was to produce a set of typical food portion weights for younger and older adults.
The individual objectives were: •
To extract food portion information from recent dietary surveys of adults (NDNS of adults aged 19-64 years and people aged 65 years and over).
•
To collate current information on portion sizes of packaged foods and fast foods commonly eaten.
11
•
To produce a list of typical food portion sizes for each age range.
•
To trial the use of typical food portion weights in dietary surveys.
•
To produce list of portion sizes for foods for adults and older people.
5. Experimental Procedures 5.1 Overview Using the data available from the NDNS surveys of adults aged 19-64 and people aged 65 years and over, average portion weights for different age groups were calculated and tested using food diaries of adults from surveys carried out by the University of Dundee. Food manufacturers, supermarkets and fast food/ restaurant chains were contacted to obtain information on portion sizes of packaged and ready to eat foods.
5.2 Methods 5.2.1 Calculation of Typical Portion Weights The databases of the NDNS were obtained from the Data Archive at the University of Essex and individual records of weights of food eaten (i.e. served minus leftovers) were extracted. Within the databases food portion weights are recorded as weighed or estimated. It was decided to do the initial analysis using both types of portion weights as exclusion of the estimated values (approximately 40% of weights used for portion size estimation) would have considerably reduced the number of foods for which typical portion sizes could be calculated. Foods were grouped by similar type and composition and a list was compiled of grouped foods.
This was further refined as work
progressed and decisions were taken to merge and split some of the new food groupings following statistical testing to check the similarity of medians. No cut-off points for inclusion were used and all similar foods regardless of the number of times they had been consumed were included in the food groupings. Those food groupings with 10 or more consumers (in either of the 19-64 or 65+ NDNS databases) were included in the list of foods for which portion sizes were calculated (food groupings with less than 10 consumers in both NDNS databases were coded as insufficient numbers). Food groupings were allocated a new code and food name in order to facilitate processing. A list of new food groupings with constituent foods is given in Appendix 1. Foods that have different portion weights depending on the mode of use were given different codes where possible. These were milk, tuna and baked beans expressed as, for example, milk in tea, milk on cereal. 12
A comprehensive analysis of the factors affecting portion size, including age, gender, illness, time of day and (in the elderly) free-living or institutional was then carried out. The following commonly used age group categories were used: 19-34, 35-49, 50-64, 64-74 and 75+. The results of the analysis showed that it was necessary to restrict the number of foods for which portion size is recorded for the gender and age groups as some numbers were insufficient to calculate a reliable portion size.
As the data were highly variable, with a
significant number of extreme values non-parametric methods were used to look at the factors that caused a significant difference in portion weights. Where these differences occurred and numbers were sufficient individual medians were calculated for the appropriate group e.g. age group, gender or both. In addition, where there were significant differences in portion weight between free-living and institutionalised subjects for over 65 year olds a separate portion weight was calculated for institutionalised subjects. A list of the numbers of consumers of each food grouping by age group and gender is given in Appendix 2. Further to statistical testing, foods where portion sizes were to be calculated by age and/or gender, or those where it was not possible or not necessary to give an age and/or gender specific portion size are listed in Appendix 3. Median with 25th and 75th percentiles were calculated (for both weighed and weighed and estimated weights) for each new food grouping split by age and/or gender where appropriate. Due to the within subject variation in portion size, all occasions of consumption of each food were used to calculate the median weights rather than a mean weight being calculated for each subject prior to calculating the median weight.
5.2.2 Testing of Typical Portion Weights To test the use of the calculated portion sizes, weighed food diaries of Scottish mothers aged 25-46 years (n 35) collected 1996-1997 and men and women aged 40-74 (n 64) collected 1999-2002, were reanalysed for energy and nutrients using the actual and calculated weights (medians) for each food. Two sets of calculated weights were used, those based on weighed only values and those 13
based on weighed and estimated values.
A database was constructed in
Microsoft Access to validate the calculated portion sizes against the weighed food diaries. Weights of the foods in each food diary were entered into the database and checked. Any foods where no calculated portion weight was available e.g. individual chocolates were entered in the missing foods part of the data entry form for further inspection.
The resulting tables were then
linked to tables containing data on calculated portion sizes and nutrient composition (derived from the NDNS nutrient databank) for the most commonly eaten food in each of the food groupings. This enabled the creation of a file containing the mean daily energy (kJ) and nutrient intakes for each of the diaries from actual and calculated portion weights. The methods of Bland and Altman16 were used to investigate the agreement between nutrient intakes calculated from actual and calculated portion weights.
5.2.3 Manufactured and Catered Portion Weights Food manufacturers, supermarkets and fast food/ restaurant chains were contacted and information on portion sizes was obtained. Supermarkets were visited and an extensive search of websites made to obtain further information.
14
6. Results 6.1 Calculated Portion Weights Weighed dietary records from 3411 individuals (2999 free-living and 412 institutionalised) were available from the 2 NDNS surveys (age and gender data was not available for 94 individuals in the 19-64 age group). Similar foods were grouped into 751 food groupings, (with 4 further food groupings of NDNS grouping
not
appropriate
(n=3),
discontinued
supplement/medicine and insufficient numbers).
foods
(n=3),
The foods reported in the
final list (Appendix 1) covered all food groups including pasta, rice, pizza, bread, breakfast cereals, biscuits, cakes, puddings, milk (served in various forms), cheese, yogurt, eggs, meat, meat dishes, fish, vegetables (including potatoes in different forms), fruit, savoury snacks, confectionery and beverages. Appendix 3 shows that overall 184 foods were allocated age/gender specific weights, 121 foods age specific weights, 55 gender specific weights and 391 foods had weights for all ages allocated (185 of these were due to no statistical difference being noted and 206 due to less than 50 records being available). Median portion weights with 25th and 75th percentiles and counts of the number of times the foods are consumed are given in Table 1. For each age group portion weights are given first as the median with 25th and 75th percentiles for all ages (excluding institutionalised when statistically different). The age group and/or gender specific median (assigned as listed in Appendix 3) with 25th and 75th percentiles is then given. Where there is no data or the count for the age/gender specific portion weight is less than 5 no weight is given and it is advised that the ‘all age groups’ portion weight is used It should also be noted that where there was no statistical difference: for age or gender - the ‘all age groups’ portion is given in these columns, for gender (but there was for age) - the age specific weight is the same for both genders for age (but there was for gender) - the gender specific weight is the same for all ages
15
Portion weights (for 110 foods) for institutionalised individuals over 65 years are given separately where significantly different from those of free living individuals. The food code and name of the foods where this is the case are highlighted in the lists of portion weights for the 65-74 and 75+ age groups. 6.2 Testing of Typical Portion weights During the testing phase, only foods recorded as being weighed in the food diaries (or where the weight had been taken from the packet) were entered. Foods which appeared more than once in the food diaries but where no calculated portion weight was available were: Golden Grahams, Corn pops, farl/soda bread, hot dog rolls, pan bread, French toast, sandwich fillings (egg mayonnaise, salad), made up sandwiches, rolls and wraps, beef olives, stovies, venison, pot noodle, BBQ chicken, crispy pancake, white pudding, fruit pudding, square sausage, salads (plated, mixed, pasta), mixed vegetables, fruit compote, dried figs, Mr Kipling cakes, marshmallow type snowball, individual chocolates, Fry's chocolate cream, Aztec bar, Dime Bar, Swiss tablet, marshmallows, Toffifee and made up hot drinks. Most of these foods will have a manufactured portion weight. The others had calculated weights for their components e.g. bread, spread and cheese in a sandwich but component weights were not available in the diaries used for testing. Investigation of results obtained using calculated portion weights from weighed only data of the NDNS suggested that numbers were too small in many of the food groupings to provide a reliable estimate of portion size. Testing showed that there was little difference in the energy and nutrient intakes obtained from the weighed only foods versus the weighed and estimated foods.
Therefore only median weights calculated from both the
weighed and estimated foods together are provided.
Bland Altman plots (Appendix 4) to assess agreement, displaying the differences between the energy and nutrient intakes from the actual and calculated portion weights, showed that the mean differences were small for females aged 19-34 (n=15), 35-49 (n=21), 50-64(n=21) and 65-74 (n=10) but considerably larger for males aged 35-49 (n=6), 50-64 (n=17) and 65-74 (n=9). 16
For example, amongst men mean intakes of energy were generally over 1000kJ greater, and mean protein intakes between 10 and 20g greater when calculated using actual weights as opposed to using the calculated weights. In all but 4 of the 70 comparisons, (kJ, carbohydrate, total sugar and vitamin C intake in 1934 year old females) mean intakes calculated from actual weights were similar or greater than those from the calculated weights. However most individual values lay within 2 standard deviations of the mean difference. The calculated typical portion weights, calculated as the median of estimated and weighed portion sizes from the NDNS surveys are listed in Table 1. 6.2 Manufactured foods portion weights (as item weight or weight served) 6.2.2 Manufactured and Supermarket Foods Portion weights of packaged foods were collected for an extensive range of foods as listed in Appendices 5 and 6 by manufacturer or supermarket. Weights of product size with additional information to specify what the weight refers to e.g. per biscuit, are given. Manufacturer information on portion size, where it does not refer to the whole product or a fraction of the product are not given as many of these are taken from the published food portion size book and not necessarily what an individual is likely to eat. It was felt that the food portion weights calculated for this project from the recent NDNS surveys would be more appropriate, as for many of the items they are age and/or gender specific.
6.2.3 Fast Food Outlet and Restaurant Chain Data Portion size information where available for fast food / restaurant chain foods are listed in Appendix 7, by outlet.
17
7. Discussion and Conclusions Data from weighed food diaries from the two NDNS surveys provided a suitable database from which to calculate typical portion sizes of over 700 different foods.
These portion sizes were shown to give similar mean results in
nutritional analysis to that from actual weights recorded in food diaries for 67 females aged 19-74 but gave lower values for 32 males aged 35-74. This is likely to be due to the fact that fewer male diaries were analysed and that some of these diaries recorded large portion sizes that could not be checked. In addition half the typical food portions weights were based on an overall figure rather than an age and/or gender specific weight, and this would be likely to have a greater reducing effect (particularly if the portion weight was calculated from a small sample where females made up half or more of the sample) on the smaller sample of male diaries. Overall the testing process was limited in that 36 foods appeared more than once in the food diaries but no calculated portion weight was available for them (in this case the actual weight was excluded as well). In practice it would be expected that researchers would give the nearest possible weight or use a portion weight from the list of manufactured or catered portion sizes if they were analysing an estimated food diary or had unweighed items in a weighed diary. For a food frequency questionnaire or a similar tool where only known popular foods are listed this should not be a problem. In addition 194 (i.e. 25% of the 751) foods for which portion weights had been calculated did not appear in the food diaries. It is recommended that further work is carried out to address any anomalies due to small numbers of diaries being tested, and to cover more of the foods for which weights have been calculated. It is worth noting that Welten and colleagues10 also found that standard portion sizes gave lower mean estimates of energy and nutrient intakes than reported portion sizes and differences were greater in men (n 2307) than in women (n 411). They did not use age/gender specific weights but it would be expected that the increased numbers in their survey would have improved agreement
18
but this did not seem to be the case. They suggested a method to adjust portion sizes which could be further explored. In conclusion, this project has enabled typical portion weights for adults to be updated, and for age/gender specific portion weights to be calculated for an extensive range of food items. In the current climate where portion weights are continually increasing, these portion weights provide a more up to date estimate of current food intakes. These typical portion weights will enable researchers to apply more up to date portion weights to surveys and associated analysis software.
They should be particularly useful for the
proposed rolling programme of NDNS surveys
using the multiple pass 24
17
hour recall method .
Further work to validate the use of typical portion sizes in males aged 19-34, males and females aged 75+ and institutionalised individuals aged over 65 should be carried out. It would also be useful for weighed food diaries that become available from projects currently underway, at the University of Dundee to be used in further testing, particularly for those age groups where numbers are small.
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8. Acknowledgements We would like to thank the Food Standards Agency for funding this project. We are very grateful to all the food manufacturers, supermarkets, fast food outlets and restaurant chains who provided us with data on portion weights. We would also like to thank Elizabeth Burrows, Julie Allison, Catherine Ferguson, Ann Laing and John Connaghan who assisted in data entry and analysis and Angela Craigie who provided advice as a user of the current food portion weights publication.
NDNS data was obtained from the Data Archive at the University of Essex: www.data-archive.ac.uk
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9. References Food Standards Agency (2002), Food Portion Sizes. Third Edition. London: HMSO. Gregory J, Foster K, Tyler H and Wiseman M (1990) The Dietary and Nutritional Survey of British adults. Office of Population Censuses and Surveys. London: Her Majesty’s Stationery Office. Henderson L, Gregory J, Swan G. (2002) The National Diet and Nutrition Survey: adults aged 19-64 years. Volume 1: Types and quantities of foods consumed. London: TSO. Technical Report to the National Diet and Nutrition Survey: adults aged 19-64 years available online at: http://www.food.gov.uk/science/101717/ndnsdocuments/ndnsdocssection1
Young, LR & Nestle, M (2002) The contribution of expanding portion sizes to the US obesity epidemic. Am. J Public Health 92, 246-249. Rolls, BJ, Morris,EL &Roe,LS (2002) Portion size of food affects energy intake in normal and overweight men and women. Am J Clin.Nutr 76 (6) 1207-1213 Department of Health (1991), Dietary Reference Values for Food Energy and Nutrients for the United Kingdom. Department of Health report on Health and Social Subjects 41. London: HMSO Food Standards Agency (2002) McCance and Widdowson's The Composition of Foods (6th Summary Edition). London: Royal Society of Chemistry, Food Standards Agency and Institute of Food Research. Bolton-Smith C & Milne AC (1991) Food frequency v. weighed intake data in Scottish men Proc Nutr Soc. 50(1) 35A Welten DC.,Carpenter RA, McPherson RS, Brodney S, Douglass D, Kampert JB & Blair SN. (2000) Comparison of a dietary record using reported portion size versus standard portion size for assessing nutrient intake. Public Health Nutrition, June 2000, 3(2), pp.151-158(8). Nelson M, Atkinson M & Meyer J. (1997) A Photographic Atlas of Food Portion Sizes, London: MAFF Publications. Gregory JR et al. (1995), National Diet and Nutrition Survey: Children Aged 1½ to 4½. Volume 1: Report of the Diet and Nutrition Survey, London: HMSO. 21
Gregory J et al. (2000) National Diet and Nutrition Survey: young people aged 4-18 years. Volume 1: Report of the diet and nutrition survey. London: The Stationery Office. Technical Report to the Food Standards Agency: Children’s food portion sizes: estimation of typical portion sizes for children of different ages Project Number N08018, September 2002. Finch S et al (1998) National diet and nutrition survey: people aged 65 years and over Volume 1: report of the diet and nutrition survey.
London: The
Stationery Office 1998 Bland, J.M. and D.G. Altman, Statistical methods for assessing agreement between two methods of clinical measurement. The Lancet, 1986(February 8): 307-310. Advisory committee on research discussion paper ACR 083/9 AGENDA ITEM 6, 26
JULY
2005
NATIONAL
DIET
AND
PROGRAMME http://www.food.gov.uk/multimedia/pdfs/acr083_9.pdf
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NUTRITION
SURVEY
ROLLING
Table 1: Calculated Portion Weights Median portion weights with 25th and 75th percentiles and counts of the number of times the foods are consumed are given in the following table. For each age group and/or gender the specific median (assigned as listed in Appendix 3) with 25th and 75th percentiles is given. Where there is no data or the count for the age/gender specific portion weight is less than 5 no weight is given and it is advised that the ‘all age groups’ portion weight is used. Thus the last column (headed All Age Groups) shows the portion weights as the median with 25th and 75th percentiles for all ages.
The following should be noted: •
The ‘all age group’ portion weight is given where there is no statistical difference between age or gender or where less than 50 records are available in the NDNS databases for the food.
•
The age specific weight is the same for both genders where there is no statistical difference in gender (but there is for age).
•
The gender specific weight is the same for all ages where there is no statistical difference in age (but there is for gender).
Portion weights (for 110 foods) for institutionalised individuals over 65 years are given separately where significantly different from those of free living individuals The food code and name of the foods where this is the case are highlighted in the lists of portion weights for the 65-74 and 75+ age groups. The 25th and 75th percentiles are provided primarily to report the variation in portion size. However it is anticipated that they could be used to represent small or large portion sizes for the particular group.
23
Appendices
1
Food Groupings with Constituent NDNS Foods
2
Food Groupings by Age Group and Gender
3
Calculated Food Portion Weight Splits
4 Bland Altman plots for selected nutrients derived from calculated and actual food portion sizes 5
Food Manufacturers Portion Weights
6
Supermarket Portion Weights
7
Fast Food & Restaurant Chain Portion Weights
24
