the subjects were enrolled in a health survey , which started in 19701973 ( 17 ) .
all 50-year - old men living in the municipality of uppsala at the time were invited to participate in a health survey on risk factors for coronary heart disease .
about 20 years later , a follow - up investigation of the 70-year - old 
a total of 855 men have been investigated and a subgroup ( n = 75 ) was randomly selected and asked to take part in the present study .
the men visited the metabolic clinic at the university hospital as part of the ongoing health survey .
those who agreed to report their dietary intake during two separate weeks were included in the present study .
the subjects were recruited throughout november and may and were randomly assigned to start either with the orfr or with the wr .
each subject was weighed initially and at the end of each dietary recording period including seven consecutive days , with a break of one week between the two periods .
each subject received detailed oral and written instructions from a dietician or nurse on how to record food intake using the wr or the orfr , as well as instructions on how to use the scales .
information on how to fill in the records correctly was also given in a video film that was shown to each participant .
subjects were instructed to continue their normal eating habits , and to start filling in the dietary record the following day .
if further questions arose during the week of reporting , subjects were instructed to contact the dietician or nurse by phone for assistance .
each subject recorded his intake in the orfr by marking a horizontal pencil stroke in a 
circel. each page of the orfr contains pre - printed food items or dishes eaten at main meals , and the subject has to mark the amount of food eaten , expressed either in household measurements or as portion sizes .
the portion sizes were illustrated in a series of four photographs , as a guide to estimating the portions of the meal components ( meat / fish ; potatoes / pasta / rice ; vegetables / salad , etc . ) .
use of spreads on sandwiches was also estimated with the help of photographs showing four alternatives for the amounts used .
for the other pre - printed foods , the subject indicated the amount consumed in household measures , e.g. glasses , cups , slices , etc .
others were described by the subjects in free text and were coded into the computer by hand in accordance with the national food administration 's food composition database ( 18 ) .
each page was read by an optical reader ( kaiser omr 32 ) using the omr technique , where the position of the marking on the page constitutes the necessary information .
the optical reader is equipped with an extra - sensitive head for reading , which sends out visible light at a reading speed of 3,000 pages / h . the reader is linked to a pc .
the kaiser lepron program transfers the data to the pc , where it is accessed and analysed .
the subjects were instructed to weigh all the foods eaten during the seven - day period using a scale ( soehnle , model 8020 ) .
as the subjects were retired men , the majority of their meals were eaten at home , according to a regular eating pattern .
if for any reason they were to eat away from home , they were asked to bring the scale with them . in some situations where they were unable to weigh their food , they would estimate their food intake using the same set of photographs as for the orfr .
the subjects were instructed to record their intake of food and beverages in a small notebook specially prepared for the present study .
further , they were instructed to record any intake as soon as possible after consumption of any food or drink .
all subjects were asked to collect a 24-h urine sample during the weighed food record period .
protein intake was validated by comparing the estimated intake from the food records with the protein intake calculated from the 24-h un excretion ( 9 ) .
the subjects were given a plastic litre measure for collecting the urine , and two - litre plastic bottles for storing the urine collections .
the first morning urine voided on the collection day was discarded and the time noted .
all urine passed in the next 24 h was collected until the same time the next morning . to check the completeness of urine collection , para - amino - benzoic acid ( paba ) tables were used ( 10 , 11 ) .
the subjects were instructed to take the paba tablets ( 380 mg ) during the 24-h urine collection .
one tablet was taken with each of the three main meals , i.e. breakfast , lunch and dinner . to include all days of the week ,
un excretion was converted to grams of protein ingested using the formula gram n/0.81  6.25 , as suggested by bingham and cummings ( 10 ) , as it was found that , on average , 81% of the nitrogen is excreted with the urine .
the daily intakes of energy and selected nutrients were calculated using a computerised dietary assessment program ( 19 ) equipped with a food composition database from the national food administration ( 20 ) .
the database includes about 1,500 food items , drinks and standard recipes , and reports data on energy and 47 nutrients .
the adequacy of the recorded ei values was evaluated using the cut - off method , according to goldberg et al .
a cut - off value below 1.27 for ei / estimated bmr was used to identify subjects with apparent long - term under - reporting .
this value is considered as the lower limit for long - term survival ( 21 ) .
in addition , a cut - off value of 1.1 was used to characterise subjects with an 
implausibly low ei for a seven - day period based on statistical considerations described by goldberg et al . ( 23 ) . the statistical analysis system ( 24 ) for personal computers
for comparison of means of normally distributed variables , the paired student 's t - test was used . for variables
correlation analysis was performed with spearman 's rank correlation to test for the trend in the different quintiles of the main variables ( 25 ) .
the subjects were enrolled in a health survey , which started in 19701973 ( 17 ) .
all 50-year - old men living in the municipality of uppsala at the time were invited to participate in a health survey on risk factors for coronary heart disease .
about 20 years later , a follow - up investigation of the 70-year - old 
a total of 855 men have been investigated and a subgroup ( n = 75 ) was randomly selected and asked to take part in the present study .
the men visited the metabolic clinic at the university hospital as part of the ongoing health survey .
those who agreed to report their dietary intake during two separate weeks were included in the present study .
the subjects were recruited throughout november and may and were randomly assigned to start either with the orfr or with the wr . each subject was weighed initially and at the end of each dietary recording period including seven consecutive days , with a break of one week between the two periods .
each subject received detailed oral and written instructions from a dietician or nurse on how to record food intake using the wr or the orfr , as well as instructions on how to use the scales .
information on how to fill in the records correctly was also given in a video film that was shown to each participant .
subjects were instructed to continue their normal eating habits , and to start filling in the dietary record the following day .
if further questions arose during the week of reporting , subjects were instructed to contact the dietician or nurse by phone for assistance .
each subject recorded his intake in the orfr by marking a horizontal pencil stroke in a 
circel. each page of the orfr contains pre - printed food items or dishes eaten at main meals , and the subject has to mark the amount of food eaten , expressed either in household measurements or as portion sizes .
the portion sizes were illustrated in a series of four photographs , as a guide to estimating the portions of the meal components ( meat / fish ; potatoes / pasta / rice ; vegetables / salad , etc . ) .
use of spreads on sandwiches was also estimated with the help of photographs showing four alternatives for the amounts used .
for the other pre - printed foods , the subject indicated the amount consumed in household measures , e.g. glasses , cups , slices , etc .
others were described by the subjects in free text and were coded into the computer by hand in accordance with the national food administration 's food composition database ( 18 ) .
each page was read by an optical reader ( kaiser omr 32 ) using the omr technique , where the position of the marking on the page constitutes the necessary information .
the optical reader is equipped with an extra - sensitive head for reading , which sends out visible light at a reading speed of 3,000 pages / h . the reader is linked to a pc . the kaiser lepron program transfers the data to the pc , where it is accessed and analysed .
the subjects were instructed to weigh all the foods eaten during the seven - day period using a scale ( soehnle , model 8020 ) .
as the subjects were retired men , the majority of their meals were eaten at home , according to a regular eating pattern .
if for any reason they were to eat away from home , they were asked to bring the scale with them . in some situations where they were unable to weigh their food , they would estimate their food intake using the same set of photographs as for the orfr .
the subjects were instructed to record their intake of food and beverages in a small notebook specially prepared for the present study .
further , they were instructed to record any intake as soon as possible after consumption of any food or drink .
all subjects were asked to collect a 24-h urine sample during the weighed food record period .
protein intake was validated by comparing the estimated intake from the food records with the protein intake calculated from the 24-h un excretion ( 9 ) .
the subjects were given a plastic litre measure for collecting the urine , and two - litre plastic bottles for storing the urine collections .
the first morning urine voided on the collection day was discarded and the time noted .
all urine passed in the next 24 h was collected until the same time the next morning . to check the completeness of urine collection , para - amino - benzoic acid ( paba ) tables were used ( 10 , 11 ) .
the subjects were instructed to take the paba tablets ( 380 mg ) during the 24-h urine collection .
one tablet was taken with each of the three main meals , i.e. breakfast , lunch and dinner . to include all days of the week ,
un excretion was converted to grams of protein ingested using the formula gram n/0.81  6.25 , as suggested by bingham and cummings ( 10 ) , as it was found that , on average , 81% of the nitrogen is excreted with the urine .
the daily intakes of energy and selected nutrients were calculated using a computerised dietary assessment program ( 19 ) equipped with a food composition database from the national food administration ( 20 ) .
the database includes about 1,500 food items , drinks and standard recipes , and reports data on energy and 47 nutrients .
the adequacy of the recorded ei values was evaluated using the cut - off method , according to goldberg et al .
a cut - off value below 1.27 for ei / estimated bmr was used to identify subjects with apparent long - term under - reporting .
this value is considered as the lower limit for long - term survival ( 21 ) .
in addition , a cut - off value of 1.1 was used to characterise subjects with an 
implausibly low ei for a seven - day period based on statistical considerations described by goldberg et al . ( 23 ) .
the statistical analysis system ( 24 ) for personal computers release 6.04 was used for the statistical analyses .
the results are expressed as means  standard deviation . for comparison of means of normally distributed variables ,
correlation analysis was performed with spearman 's rank correlation to test for the trend in the different quintiles of the main variables ( 25 ) .
seventy - three of the 75 men completed both recordings : one week using the optical readable food record and one week using the weighed food registration method .
there were no significant differences in body weight from baseline , orfr 82.7  11.4 kg and wr 82.5  11.4 kg , to the end of either of the two dietary recording periods , orfr 82.7  11.5 kg and wr 82.7  11.2 kg , or between the two methods used .
the mean daily intakes of energy and selected nutrients as measured with the two methods are shown in table 1 .
higher average intakes were obtained by the wr for energy and protein , total fat , carbohydrates ,  - carotene , vitamin d , -tocopherol , thiamin , riboflavin , preformed niacin , vitamin b6 , folate , vitamin c , magnesium , iron , zinc , selenium and dietary fibre . however , the proportion of energy ( e% ) from energy - yielding nutrients was similar , except for a higher e% saturated fatty acids and alcohol , and a lower e% sucrose , with the orfr method . 
 
average daily intakes of energy , nutrients and alcohol as measured by the orfr and the weighed record ( wr ) ; mean and ( sd ) ( n = 73 ) values significantly different from weighed record : * p < 0.05 ; * * p < 0.01 ; * * * p < 0.001 . when expressed as nutrient density ( i.e. amount per mj ) , the orfr yielded lower nutrient density for iron , calcium ,  - carotene , selenium , - tocopherol and dietary fibre , while a higher nutrient density was found for potassium ( table 2 ) .
lower intakes per mj were also obtained with the orfr for the fatty acids 16:1 , 18:1 and 18:3 n-3 and the long - chain n-3 fatty acids 20:5 and 22:6 ( data not shown ) . 
  nutrient density ( per mj ) according to orfr and wr ( n=73 ) significant difference between orfr and wr : * p < 0.05 ; * * p < 0.01 ; * * * p < 0.001 .
the correlation coefficients ( spearman ) between the two dietary assessment methods for intakes of energy and nutrients ranged from 0.08 to 0.68 and were all significant ( p < 0.01 ) . moderate to high correlation coefficients , > 0.400.60 , were obtained for energy and most energy - yielding nutrients ( table 3 ) , while coefficients were between 0.30 and 0.50 for most micro - nutrients ( table 4 ) .
lower figures ( < 0.30 ) were obtained for vitamin a , vitamin d ,  - carotene , thiamin , riboflavin , preformed niacin and sodium .
a comparison of the ranking of the individual intakes of energy and selected nutrients showed that the majority were classified into the same quintile or nearest quintile , i.e. the one below or the one above ( table 4 ) . 
 
cross - classification ( quintiles ) and correlation of intakes of energy , energy - yielding nutrients and dietary fibre ( in absolute and energy - adjusted values ) , according to orfr and wr 
                         percent subjects in first quintile wr classified into first and second quintiles in orfr . 
                        
percent subjects in fifth quintile wr classified into fourth and fifth quintiles in orfr . 
                        
significance of the spearman correlation : * p < 0.01 ; * * p < 0.001 . cross - classification ( quintiles ) and spearman correlation for daily intakes of selected nutrients measured by the orfr and the weighed record ( wr ) ( n = 73 ) 
                         percent subjects in first quintile wr classified into first and second quintiles in orfr . 
                        
significance of the spearman correlation : * p < 0.01 ; * * p < 0.001 .
all subjects ( n = 73 ) collected a 24-h urine sample during the weighed food record period . as we considered urine samples with a recovery of less than 85% incomplete ,
the daily protein intake estimated using orfr was 31% lower than the calculated values from the 24-h un ( p < 0.0667 , r = 0.59 ) , while that estimated using the wr was 22% lower ( p < 0.0001 , r = 0.27 ) ( table 5 ) . 
 
intake of protein ( g / d ) measured by orfr , wr and 24-h urinary nitrogen excretion ( un ) .
the figures are presented as mean and ( sd ) and their correlation ( n = 59 ) significance difference from urinary protein : * p < 0.0001 .
significance of spearman correlation : * * p < 0.05 . the average daily consumption of foods ( aggregated into major food groups ) obtained by the two methods is shown in table 6 .
the consumption of cheese , milk and other milk products as well as coffee , tea and alcohol was significantly higher when estimated using the orfr method than when using the wr method , while the opposite was seen for vegetables , meat and meat products , fish , bread , cereals and pasta , cakes and biscuits , jam , sweet drinks and desserts , chocolate and sugar ( table 6 ) .
no differences were seen for spreads , potatoes , fruit , juice and eggs . 
 
average consumed amounts , mean and ( sd ) of food among healthy , elderly men according to the optically readable food record ( orfr ) and the weighed record ( wr ) ( n = 73 ) a large proportion of the men under - reported their ei .
use of the cut - off point < 1.27 ( 21 ) showed a majority of the men reported an ei below this value when using the orfr and wr , respectively .
further , it was found that a higher percentage had an implausibly low ei according to goldberg , i.e. cut - off < 1.1 ( 23 ) , when using the orfr ( 26% ) than when using the wr ( 12% ) .
seventy - three of the 75 men completed both recordings : one week using the optical readable food record and one week using the weighed food registration method .
there were no significant differences in body weight from baseline , orfr 82.7  11.4 kg and wr 82.5  11.4 kg , to the end of either of the two dietary recording periods , orfr 82.7  11.5 kg and wr 82.7  11.2 kg , or between the two methods used .
the mean daily intakes of energy and selected nutrients as measured with the two methods are shown in table 1 .
higher average intakes were obtained by the wr for energy and protein , total fat , carbohydrates ,  - carotene , vitamin d , -tocopherol , thiamin , riboflavin , preformed niacin , vitamin b6 , folate , vitamin c , magnesium , iron , zinc , selenium and dietary fibre .
however , the proportion of energy ( e% ) from energy - yielding nutrients was similar , except for a higher e% saturated fatty acids and alcohol , and a lower e% sucrose , with the orfr method . 
 
average daily intakes of energy , nutrients and alcohol as measured by the orfr and the weighed record ( wr ) ; mean and ( sd ) ( n = 73 ) values significantly different from weighed record : * p < 0.05 ; * * p < 0.01 ; * * * p < 0.001 . when expressed as nutrient density ( i.e. amount per mj ) , the orfr yielded lower nutrient density for iron , calcium ,  - carotene , selenium , - tocopherol and dietary fibre , while a higher nutrient density was found for potassium ( table 2 ) .
lower intakes per mj were also obtained with the orfr for the fatty acids 16:1 , 18:1 and 18:3 n-3 and the long - chain n-3 fatty acids 20:5 and 22:6 ( data not shown ) . 
  nutrient density ( per mj ) according to orfr and wr ( n=73 ) significant difference between orfr and wr : * p < 0.05 ; * * p < 0.01 ; * * * p < 0.001 .
the correlation coefficients ( spearman ) between the two dietary assessment methods for intakes of energy and nutrients ranged from 0.08 to 0.68 and were all significant ( p < 0.01 ) .
moderate to high correlation coefficients , > 0.400.60 , were obtained for energy and most energy - yielding nutrients ( table 3 ) , while coefficients were between 0.30 and 0.50 for most micro - nutrients ( table 4 ) .
lower figures ( < 0.30 ) were obtained for vitamin a , vitamin d ,  - carotene , thiamin , riboflavin , preformed niacin and sodium .
a comparison of the ranking of the individual intakes of energy and selected nutrients showed that the majority were classified into the same quintile or nearest quintile , i.e. the one below or the one above ( table 4 ) . 
 
cross - classification ( quintiles ) and correlation of intakes of energy , energy - yielding nutrients and dietary fibre ( in absolute and energy - adjusted values ) , according to orfr and wr 
                         percent subjects in first quintile wr classified into first and second quintiles in orfr . 
                        
percent subjects in fifth quintile wr classified into fourth and fifth quintiles in orfr . 
                        
significance of the spearman correlation : * p < 0.01 ; * * p < 0.001 . cross - classification ( quintiles ) and spearman correlation for daily intakes of selected nutrients measured by the orfr and the weighed record ( wr ) ( n = 73 ) 
                         percent subjects in first quintile wr classified into first and second quintiles in orfr . 
                        
significance of the spearman correlation : * p < 0.01 ; * * p < 0.001 .
all subjects ( n = 73 ) collected a 24-h urine sample during the weighed food record period . as we considered urine samples with a recovery of less than 85% incomplete , only 59 samples were used for comparison with the respective dietary records .
the daily protein intake estimated using orfr was 31% lower than the calculated values from the 24-h un ( p < 0.0667 , r = 0.59 ) , while that estimated using the wr was 22% lower ( p < 0.0001 , r = 0.27 ) ( table 5 ) . 
 
intake of protein ( g / d ) measured by orfr , wr and 24-h urinary nitrogen excretion ( un ) .
the figures are presented as mean and ( sd ) and their correlation ( n = 59 ) significance difference from urinary protein : * p < 0.0001 .
the average daily consumption of foods ( aggregated into major food groups ) obtained by the two methods is shown in table 6 .
the consumption of cheese , milk and other milk products as well as coffee , tea and alcohol was significantly higher when estimated using the orfr method than when using the wr method , while the opposite was seen for vegetables , meat and meat products , fish , bread , cereals and pasta , cakes and biscuits , jam , sweet drinks and desserts , chocolate and sugar ( table 6 ) .
no differences were seen for spreads , potatoes , fruit , juice and eggs . 
 
average consumed amounts , mean and ( sd ) of food among healthy , elderly men according to the optically readable food record ( orfr ) and the weighed record ( wr ) ( n = 73 )
use of the cut - off point < 1.27 ( 21 ) showed a majority of the men reported an ei below this value when using the orfr and wr , respectively .
further , it was found that a higher percentage had an implausibly low ei according to goldberg , i.e. cut - off < 1.1 ( 23 ) , when using the orfr ( 26% ) than when using the wr ( 12% ) .
the main results from the present study show that estimates of average intakes of energy and several nutrients differed significantly between the two methods , higher figures being obtained when using the wr . however , when expressed as nutrient density , i.e. per mj , only a few nutrients were still lower when using the orfr .
the mean spearman correlation coefficients between the intakes of energy and energy - yielding nutrients between the two methods were moderate to high , i.e. 0.40.6 , while figures for most micro - nutrients were in the range 0.30.5 .
the majority of the subjects intakes were classified into the same or adjacent quintile . in a series of dietary surveys
earlier performed in sweden , a pre - coded record book has been used to estimate nutrient and food intake in different groups ( 5 , 15 , 26 ) .
the record book has proven to be very useful in larger dietary investigations , but has also been found to have some limitations ( 5 , 15 ) .
one important advantage of a pre - coded record book , compared with open - ended records , is that considerable time may be saved by not having to code and enter data .
becker et al . ( 15 ) suggested that the time reduction was almost 50% : coding and data entry from the pre - coded record took 1.3 h per person as compared to 2.5 h per person for the wr . in a study including 500 participants , this means a saving of four man - months of work ( 15 , 27 ) . in the present study , a pre - coded record book designed for optical scanning
was used , which also considerably reduced the time - consuming step of entering the data manually ( 15 ) .
as reported by others , and shown here , underestimation of food intake seems to be a  general problem ,
as shown by various assessment methods ( 1 , 2 , 4 , 5 , 14 , 15 , 23 , 28 , 29 ) . the reported eis obtained here are comparable with those from a number of other large investigations in which seven - day food records were also employed ( 5 , 15 , 28 ) . in the present study
, the proportions of energy - providing nutrients did not differ significantly between the two methods , indicating that under - reporting of this aspect was not specific to the method used ( table 3 ) .
this means that the fat used for cooking , i.e. included in the recipes , is of the same quality / type ( amounts of total fat and fatty acid composition ) .
thus , if the subject uses other cooking fats with a different fat content or with a different fatty acid composition , this will not be recorded or calculated . the true picture of the dietary fat intake is thus limited when using orfr .
the same observations have been made earlier ( 4 , 5 , 15 , 17 ) .
however , when using wr , the subjects are more likely to specify the type of cooking fat , as well as the true amounts of spreads they consume , because they actually weigh every single food item and the amount they eat . in the present investigation , calculations of the adequacy of the reported ei values were made on the basis of estimated bmr values as suggested by fao / who / unu ( 21 , 22 ) and the cut - off points suggested by goldberg et al .
were categorised as under - reporters using both methods , though a larger number using the orfr method .
the proportion of subjects with implausibly low reported eis corresponds well with the findings of other surveys in which a record book ( pre - printed , but not optically readable ) was used ( ( 5 ) , 15 , 26 ) .
there is some uncertainty in the calculations of under - reporting because physical activity , specific to this study , was not assessed and cut - off limits for the ei : bmr ratio were based on those calculated by goldberg et al .
, with a sedentary physical activity level of 1.55 for n = 1 ( 4 , 23 ) .
it was further found that both assessment methods yielded lower estimates for protein intake compared to estimates based on un excretion ( table 5 ) .
the lowest calculated intakes were obtained by the orfr . despite that only a single 24-h urine was collected , correlation coefficient ( spearman ) for orfr was relatively high ( 0.59 ) , and close to figures reported by bingham et al .
( 13 ) for estimated food records ( 0.600.70 ) using eight 24-h urine per subject .
further , when we checked our results using paba , we did not include those who had < 85% completeness , as such results obviously indicate significant underestimation .
( 15 ) , also based on comparison of an open wr with the pre - coded record book .
some of the portion sizes used in the orfr provide the most probable explanation for the low figures obtained ( 5 , 15 , 30 ) .
an analysis of the food consumption figures is very much in line with the lower energy findings , as well as with some lower nutrient intake figures , when using the orfr .
lower consumption of , e.g. meat , milk and fat products can be associated with lower intakes of energy , as well as with lower intakes of the major energy - yielding nutrients such as total fat and protein , and perhaps also with some of the vitamins and minerals .
further , lower consumption of bread and cereal products , as well as vegetables , may explain lower figures for carbohydrates and dietary fibre .
in general , the portion sizes used in our orfr may have been too small for various food items and dishes . 
flat slope syndrome is another explanation , suggested by gibson ( 31 ) , for the tendency to overestimate low intakes and underestimate high intakes , and this explanation may also apply to the subjects in the present investigation . in an evaluation of portion sizes ,
hglin and co - workers ( 30 ) showed that choosing incorrect pictures may result in both under- and over - estimations .
although most elderly people are thought to have a regular meal pattern and eat most of their food at home , they may forget to weigh everything .
this could explain the low protein intakes estimated when using the wr . as stated by bingham ( 12 ) , energy and protein intakes
have been found to be under - estimated by as much as 20% according to various dietary surveys ( 12 , 33 ) .
our results , as well as those of others ( 32 ) , suggest that improvement of methods for estimating portion sizes should be a priority in future dietary assessment methodology .
after the present study was performed , the orfr was also investigated by rosell et al .
the aim of their study was to investigate how much of the energy and nutrients contributed by foods that has to be reported in free text .
the authors concluded that to reduce the level of under - reporting , emphasis should be placed on improving the recording of between - meal eating .
however , we would like to emphasise the two important advantages of a pre - coded , orfr : the recorder and the experimenter save a considerable amount of time and the accuracy of coding and data entry is increased . in a pilot study comprising 35 subjects , time savings in data entering ,
data checks and nutrient analysis were on average 30 min for the orfr compared with the manual pre - printed record book ( carlsson & johansson , unpublished data ) .
therefore , after the suggested adjustments especially in , portion sizes , the orfr could be seen as a useful tool in a variety of food and nutrition studies .
the above findings indicate that when a pre - coded food record is used this is designed for scanning , the following advantages ensue : it is less time - consuming for subjects to record their food intake because there is no need for weighing and writing.it allows more efficient data processing , e.g. by limiting time spent on data entry.a pre - coded and orfr is less expensive to process than a manual version is.emphasis should be put on estimations of the type and amount of fat used in order to obtain a valid assessment of total fat and fat quality.the portion sizes should be estimated carefully measured to reflect the actual portion sizes in the study population . 
 
it is less time - consuming for subjects to record their food intake because there is no need for weighing and writing .
it allows more efficient data processing , e.g. by limiting time spent on data entry .
a pre - coded and orfr is less expensive to process than a manual version is .
emphasis should be put on estimations of the type and amount of fat used in order to obtain a valid assessment of total fat and fat quality .
the portion sizes should be estimated carefully measured to reflect the actual portion sizes in the study population .
the author has not received any funding or benefits from industry to conduct this study .
 backgrounda simplified optically readable food record ( orfr ) was developed and compared with an open - ended weighed record ( wr).objectiveto compare intake of nutrients and foods using a seven - day orfr with intake estimated using a seven - day wr . the results from each method were validated against 24-h urinary nitrogen excretion and energy intake ( ei)/estimated basal metabolic rate ( bmr ) cut - off values.designthe study comprised 73 free - living , healthy 70-year - old swedish men . 
 dietary data were collected during seven consecutive days , starting either with wr or orfr.resultsaverage intakes of energy and several nutrients were significantly lower when estimated using orfr than when using wr . however , 
 when adjusted for nutrient density , only a few nutrients were still lower with orfr . 
 spearman correlation coefficients between the two methods regarding intakes of energy and energy - yielding nutrients were moderate to high , i.e. 0.40.6 , while figures for most micro - nutrients were in the range 0.30.5 . 
 a large proportion of subjects under - reported their eis , a higher proportion doing so when using orfr . 
 protein intake obtained using orfr was 31% lower than the values calculated from the 24-h urine nitrogen excretion , and 22% lower than those obtained from wr . 
 average intakes of milk , cheese and other milk products as well as coffee , tea and alcohol were significantly higher when estimated using orfr than when using wr , while intakes of vegetables , meat and meat products , fish , bread and cereal products as well as number of sweet foods were significantly lower with orfr.conclusionsbased on these results , adjustments of some portion sizes in orfr are suggested . in view of the advantages of orfr with respect to lower response burden and rapid processing of data , 
 such adjustments would make orfr a suitable dietary assessment tool for use in dietary surveys , including larger resource - demanding epidemiological investigations . 