Validity and reliability of a dietary assessment method: the application of a digital camera with a mobile phone card attachment

This study was aimed at evaluation of the validity and reliability of an alternative dietary measurement method that assists epidemiologic studies. We validated a handheld personal digital assistant with camera and mobile phone card, called Wellnavi, in which a 1-d weighed diet record was employed as a reference method. Twenty college students majoring in food and nutrition participated in this study. They were asked to keep a diet record and to take digital photos of all these recorded food at the same time, then send them to the dietitians by the mobile phone card. In the reliability study, other twenty students from the same college were asked to take digital photos of the same meal during a day by two same instruments under the same circumstances and to send these photos to the different dietitians electronically. With respect to validity, median nutrient intakes estimated by the Wellnavi method and the diet record method are comparable. Correlation coefficients between the median nutrient intakes estimated from these two methods ranged from 0.46 for monounsaturated fatty acid to 0.93 for vitamin B12 and copper (median r = 0.77). With respect to reliability, our data show a good agreement between two Wellnavi instruments for most of the nutrients. Correlation coefficients between the nutrient intakes estimated from 2 instruments ranged from 0.55 for vitamin B1 and water-insoluble dietary fiber to 0.92 for vitamin B12 (median r = 0.78). In conclusion, the results indicate this dietary assessment instrument can usefully measure individual dietary intakes for a variety of nutrients in an epidemiologic study.     

The application of a handheld personal digital assistant with camera and mobile phone card (Wellnavi) to the general population in a dietary survey

This study was carried out to examine first, the validity of a new dietary assessment method, a handheld personal digital assistant with camera and mobile phone card (Wellnavi), in comparison with a weighed diet record as a reference method and second, the relation between obesity and underreporting in the Wellnavi method in 27 men and 48 women volunteers aged 30-67 y from the general population. On the validity, there were significant correlations (0.32-0.75) between the daily nutrient intakes measured by the Wellnavi method and the weighed diet record method in all the subjects except for some nutrients such as iron, magnesium and vitamin E. Results similar to those from the group of all the subjects were obtained in the men's group and the women's group. In all the subjects and the men's group and the women's group, the differences in the daily nutrient intakes between the two dietary assessment methods were statistically significant. However, good agreement of the differences between the two dietary assessment methods for many daily nutrient intakes was obtained in the nonobese men. The nutrient intakes estimated by the Wellnavi method in all the subjects and the men's group and the women's group were significantly lower than those values estimated by the weighed diet record method except for some nutrients such as sodium, iron and fat-soluble vitamins. With respect to the relation between obesity and underreporting, the obesity in women was not a factor of underreporting in the Wellnavi method, but the presence of this relation was undeniable in the obese men. The reason why the values of daily nutrient intakes in the Wellnavi method were lower than those estimated by the weighed diet record method seemed to be the low quality of the digital photo of the Wellnavi instrument. By improving the digital photo quality of this instrument, the Wellnavi method could become a useful new dietary assessment method to get accurate dietary information from people of a wide range of age and occupation, and a wide variety of physical situations of subjects from the general population.     

Comparison of measures of fatty acid intake by subcutaneous fat aspirate, food frequency questionnaire, and diet records in a free-living population of US men.

In 1986-1987, the authors assessed the fatty acid intake of 118 Boston-area men, aged 40-75 years, by a semiquantitative food frequency questionnaire administered twice, by two 7-day diet records, and by capillary gas chromatography of subcutaneous fat samples obtained by needle aspirate from the lateral buttock. Spearman correlation coefficients between diet record estimates of fatty acid intake (as a percentage of total fat) and fat aspirate measures (as a percentage of total peak area) were as follows: saturated fat, r = 0.16 (p = 0.09); monounsaturated fat, r = 0.22 (p = 0.01); and polyunsaturated fat, r = 0.49 (p = 0.0001). Spearman correlation coefficients between estimates derived from the food frequency questionnaire were as follows: saturated fat, r = 0.18 ( p = 0.05); monounsaturated fat, r = 0.14 (p = 0.14); polyunsaturated fat, r = 0.50 (p = 0.0001); and eicosapentaenoic acid, r = 0.47 (p = 0.0001). These data confirm that the polyunsaturated and eicosapentaenoic fatty acid content of subcutaneous fat is a measure of dietary intake of these fats. Although diet records are commonly thought to be the "gold standard" method of dietary assessment, the similar correlations observed between the fatty acid composition of adipose tissue and estimates of intake from the food frequency questionnaire and from diet records suggest that these two dietary assessment methods have similar validity in the measurement of polyunsaturated fatty acid intake.     

Impact of the revision of a nutrient database on the validity of a self-administered food frequency questionnaire (FFQ)

BACKGROUND: Revision of the national nutrient database in 2000 had a strong impact on the absolute level of estimated nutrient intake in dietary assessments. However, whether it influenced the ranking of individuals by estimated intake, a more important function in epidemiologic studies, has not been investigated. Here, we investigated the effect of this revision of the nutrient database on the validity of a food frequency questionnaire (FFQ) used to estimate nutrient intake in the Japan Public Health Center-based prospective Study (JPHC Study). METHODS: Subjects were a subsample of the JPHC Study who volunteered to participate in the validation study of the FFQ. Validity of the FFQ was evaluated by reference to the 28-day weighed dietary records as a gold standard. Nutrient intake according to the FFQ was recalculated using the revised database, and the results were compared to those using the previous database. Spearman's rank correlation coefficients (CCs) between intakes estimated by the FFQ and dietary records were computed using the revised database, and were compared to CCs computed using the previous database. RESULTS: For most of the nutrients, mean intake increased or decreased significantly using the revised database. However, no notable change was seen for the CC between estimated intake according to dietary records and FFQ when the revised database was used for calculation. Differences in the point estimates of the CCs ranged from -0.14 to 0.15. Likewise, CCs between biomarkers and estimated intake according to FFQ were similar for the two databases. CONCLUSION: Despite changes in intake levels for many nutrients, the validity of our FFQ using rank correlation by nutrient intake was not influenced by revision of the nutrient database in Japan.     

Monitoring Dietary Change in a Low-Fat Diet Intervention Study: Advantages of Using 24-Hour Dietary Recalls vs Food Records

Objective The purpose of the study was to evaluate two methods of dietary assessment for monitoring change in fat intake in a low-fat diet intervention study.Design The two dietary assessment methods were a 4-day food record (4DFR) and an unannounced 24-hour dietary recall conducted by telephone interview (referred to as a telephone recall [TR]). Subjects were assigned randomly to either a low-fat diet intervention group or a control group that received no counseling about fat intake. Dietary data were collected at baseline, 6 months, and 12 months.Subjects Two hundred ninety postmenopausal women with localized breast cancer were recruited at seven clinical centers in the United States.Statistical analysis Analysis of variance was used to test for significant differences in mean fat and energy intakes.Results Three sources of error were identified: (a) an instrument effect, suggesting underreporting at baseline of approximately 8% in mean energy intake and 11% in mean fat intake in the TR group compared with the 4DFR group (P=.0001); (b) a repeated measures effect observed for the 4DFR, suggesting underreporting of approximately 7% for energy intake and 14% for fat intake in the control group at 6 and 12 months compared with baseline values (P<.001); and (c) an adherence effect (or compliance bias), suggesting greater compliance to the low-fat intervention diet when subjects were keeping food records than when estimates were based on the unannounced TR. Compared with the TR, the 4DFR overestimated the extent of fat reduction in the low-fat diet intervention group by 41% (P=.08) and 25% (P=.62) at 6 and 12 months, respectively.Application Multiple days of unannounced 24-hour recalls may be preferable to multiple-day food records for monitoring dietary change in diet intervention studies. J Am Diet Assoc. 1996; 96:574-579.     

A new simplified dietary history method for measuring intake of energy and macronutrients.

In this dietary history method, which preserves the characteristic features of the full dietary history, the principle of simplification is to group several food items into common codes. This enables us to complete both an interview and all nutrient calculations within 35-45 min. In this study we investigated whether the method could replace a 4-day food record for assessing individual intakes of energy and macronutrients. Dietary data were collected from 75 individuals (57 males and 18 females). Protein intake was validated by comparison with 24 h urinary nitrogen excretion (33 subjects), and energy intake was compared to weight maintenance energy intake from a later controlled diet study (19 subjects). When average intakes according to the two methods were compared, dietary history intakes were slightly higher than food record results (0-13%) except for alcohol. Comparison with urinary nitrogen excretion and energy intake data indicate that this is due to an overestimation by the dietary history method, rather than an underestimation by the food record. For individuals most of the correlations between the two methods were in the range 0.5-0.7, but alcohol correlation was down to 0.2. About 75% (53-93%) of the individuals at the extremes of the intake distribution were classified similarly by both methods. Although the ability of the dietary history to predict the individual food record results was unreliable the two methods agreed better when classifying individuals relative to certain cut-off points (sensitivity and specificity values of 0.7-0.9, relative to the food records).(ABSTRACT TRUNCATED AT 250 WORDS)     

Measuring dietary fatty acid intake:validation of a food-frequency questionnaire against 7 d weighed records

There are few validated methods of measuring dietary fatty acid intake that are suitable for epidemiological research. The purpose of the present study was to develop and validate a food-frequency questionnaire (FFQ) developed to measure individual dietary fatty acid intakes against 7 d weighed dietary records, in a sample of thirty-one healthy adult volunteers. The FFQ was based on a previously validated questionnaire (DIETQ; Tinuviel Software, Warrington, Ches., UK), adapted to include greater detail on those foods from which the majority of dietary fatty acids are obtained. The FFQ and weighed records were analysed using food nutrient data from McCance and Widdowson's Food Composition Tables, supplemented with a food fatty acid content database (Foodbase, London, UK). Results from the two dietary assessment methods were compared by correlation coefficients and limits of agreement. The mean intake of individual fatty acids tended to be lower when assessed by FFQ. Correlation coefficients comparing unadjusted individual fatty acid intakes assessed by FFQ and weighed records ranged from 0.29 for 18 : 1n-9 to 0.71 for 20 : 4n-6. Adjusting for energy intake tended to increase the correlation coefficients between saturated fatty acids and decrease those between unsaturated fatty acids. In conclusion, this food-frequency method provides reliable estimates of dietary intake of many individual fatty acids for use in epidemiological studies.     

Comparison of dietary assessment methods in a low-fat dietary intervention program

The food frequency questionnaire (FFQ) is commonly utilized for assessment of dietary fat intake, but its validity among individuals following a low-fat diet is unclear. We evaluated the agreement of nutrient estimates derived from FFQ, 24-h recall, and 3-day food records obtained from 104 participants in a randomized trial of a low-fat dietary intervention for women at elevated breast cancer risk. Comparisons were made for total calories, percent calories from fat, and total fat after 1 yr. Correlation was assessed using standard methods based on a null hypothesis of no agreement between instruments as well as by a methodology based on a null hypothesis that the instruments should be in agreement. With the use of standard methods, FFQ estimates for women on the low-fat diet were significantly correlated to records only for percent calories from fat (r = 0.39), whereas recall and record estimates were significantly correlated for all three dietary variables. Using the new method, we found no significant correlation between FFQ and either recalls or records for women following a low-fat diet but significant correlation between recall and record estimates for total calories (r = 0.67). Traditional correlation testing may overestimate the extent of agreement in dietary instruments among women on a low-fat diet. We found empirical support for the nontraditional method.     

Rapid assessment of dietary intake of fat, fiber, and saturated fat: validity of an instrument suitable for community intervention research and nutritional surveillance

Abstract Traditional methods to assess changes in dietary intake, for example food frequency questionnaires or 24-hour dietary recalls, are often not practical: they are lengthy, expensive, and unsuitable for telephone administration. This article describes the development and evaluation of an approach to the rapid assessment of the dietary intake of nutrients of most interest in health promotion research; total fat, saturated fat, dietary fiber, and percent of calories from fat. In this validation study on 97 women, short dietary questionnaires were compared to two criterion measures of usual dietary intake, a food frequency questionnaire and the mean of two four-day diet records. Correlations between self-administered short questionnaires and four-day diet records were 0.52, 0.53, 0.61, and 0.40 for total fat, percent of calories from fat, saturated fat, and dietary fiber, respectively. These correlations are similar to those observed between food frequency questionnaires and four-day diet records, which suggests that this approach to developing and administering short dietary questionnaires may be useful in situations where more expensive and time-consuming methods of dietary assessment are not practical.     

Validation of a semi-quantitative food-frequency questionnaire used among 12-month-old Norwegian infants

OBJECTIVE: To assess the validity of a semi-quantitative food-frequency questionnaire (SFFQ) used in a large nation-wide dietary survey among 12-month-old Norwegian infants. METHODS: The SFFQ was administered to the parents about 1 week before the infants turned 12-month-old. The participants filled in the SFFQ and 1-2 weeks later they kept weighed food records for a total of 7 days. Both methods were completed for 64 infants. RESULTS: The SFFQ overestimated energy intake with 25% and gave significantly higher estimates of all nutrients compared with the records, except for calcium. Much of the difference between the methods disappeared when nutrient density was compared. Spearman correlation coefficients between pairwise measurements of nutrient intakes from the food records and the SFFQ ranged from 0.18 for vitamin D to 0.72 for polyunsaturated fatty acid intake (median r=0.50). On average 38% of the infants were classified in the same quartile with the two methods, and 3% in the opposite quartile. The correlations for food items varied from 0.28 for sweetened drinks to 0.83 for commercial porridge (median r=0.62). CONCLUSION: This study indicated that the SFFQ overestimates average absolute nutrient intakes. However, the questionnaire gave better estimates for average nutrient densities than for absolute nutrient intakes. The capability of the questionnaire to rank infants according to intake of nutrients and food items was moderate, but at the same level as others have observed with food-frequency questionnaires.     

Assessing dietary intake of drug-abusing Hispanic adults with and without human immunodeficiency virus infection

OBJECTIVE: Drug abuse is an important risk factor for the human immunodeficiency virus (HIV) among Hispanics living in the northeastern United States, and both drug abuse and HIV are associated with nutritional deficiencies. The selection of a dietary assessment method most appropriate for Hispanic adults with/without HIV infection who may be drug abusers remains unclear. DESIGN: Participants were recruited into one of the three groups: HIV-infected drug abusers, HIV-noninfected drug abusers, and HIV-infected non-drug abusers. Subjects who completed two of the three dietary methods were included in cross-sectional pairwise comparisons. SETTING: The baseline data from a prospective cohort study of the role of drug abuse in HIV/acquired immunodeficiency syndrome-related weight loss. RESULTS: The 286 enrolled participants completed 282 food frequency questionnaires (FFQs), 142 3-day diet records, and 270 24-hour recalls. Energy-adjusted and deattenuated correlations between the FFQ and 3-day diet records ranged from 0.11 (carbohydrate) to 0.75 (caffeine). Twenty-seven of 33 nutrient intakes estimated by 3-day diet record were significantly lower than by FFQ (P<0.05). Three-day diet records underestimated dietary intake relative to the FFQ and 24-hour recall methods. Fifty percent of records were not completed. Energy estimates from the FFQ and 24-hour recall were similar to each other. CONCLUSIONS: The 24-hour recall gave higher mean dietary intake estimates, but would require multiple contacts with this difficult-to-reach population. The FFQ that was specifically designed for this Hispanic population performed well relative to the other methods.     

Comparison of techniques for estimating nutrient intake: the Framingham Study.

We compared estimates of nutrient intake by three diet assessment methods (24-hour recall, 3-day food record, food frequency questionnaire) in a random sample of 73 females and 77 males from the Framingham Offspring/Spouse Study. The results differed according to analytic method. Estimates of group mean intake from the 24-hour recall and 3-day records were similar in both women and men, with differences of less than 10% for most nutrients. The estimates of mean intake calculated from the food frequency questionnaire generally differed from those obtained by the other methods, with higher estimated intakes in women and generally lower estimated intakes in men. Spearman rank correlations between the individuals' nutrient intakes estimated by the three diet assessment methods were modest (r = 0.08-0.68, most below 0.50) and comparable in the comparisons of the 24-hour recall or food frequency questionnaire with the 3-day records. Our data suggest the interchangeability of the recall and record methods and their preference over the food frequency questionnaire for mean estimates of group nutrient intake. The food frequency questionnaire appears to be of some utility in ranking individuals according to the usual intake, although these data are not informative in comparing this method with multiple days of recall or records beyond 3 days. This research underscores the need to develop and evaluate short methods of diet assessment in specific populations of interest.     

Relative validity of a diet history interview in an intervention trial manipulating dietary fat in the management of Type II diabetes mellitus

BACKGROUND: This study assesses the relative validity of a diet history interview in 56 free-living individuals with Type II diabetes mellitus. METHODS: The diet history interview was compared to a 3-day food record in a 1-year dietary intervention trial. The plausibility of energy intake data was examined throughout the trial. Paired data were compared for differences and the presence of systematic error was determined by Bland Altman analysis. Changes in accuracy and responsiveness were assessed over time. RESULTS: The proportion of underreporters was larger in the diet history at baseline. Underrecording with the food record was more common in subjects with BMIs > 30 kg/m(2). There was no difference between paired dietary data from the two methods; however, data on fatty acids failed to correlate. These correlations improved when outliers were removed. There was no evidence of a relationship between bias and mean intake of dietary variables. Accuracy of diet history measurement did not change during the trial for energy or macronutrients, but data on protein and monounsaturated fat were both affected by BMI. The diet history was more responsive than the food record to changes in monounsaturated fatty acid intake after 3 months, but this changed at the end of the trial. CONCLUSION: The diet history provided good estimates of energy and macronutrient intakes in a sample group with Type II diabetes mellitus. However, energy intake data revealed a high prevalence of underreporting especially in people with higher BMIs.     

Dietary assessment in children using electronic methods: telephones and tape recorders

Selection of dietary assessment methodology is important in dietary intervention studies. Few studies have reported the relative merits of various assessment methods or the feasibility of electronic methods in pediatric populations. Parent-child dyads performed telephone recalls (no. = 32) and tape recorded dietary records (no. = 33). Traditional recalls were first conducted to familiarize parents and children with the telephone recall procedure, to introduce two-dimensional food models, and to instruct on the use of the tape recorder. Parents monitored and documented as unobtrusively as possible the child's intake on the day before the telephone recall and also on the day of the taped record. Children were called at random to reduce bias. Simple correlation coefficients (r) were calculated for nine nutrients and calories for both methods. For telephone recalls, values ranged from a low of r = .64 for saturated and polyunsaturated fat to r = .85 for cholesterol and r = .93 for iron. Tape-recorded data yielded r = .80 or above, except calories with r = .68 (p less than .001 for all values, 1-tail tests). Mean nutrient values were within expected ranges, e.g., 1,800 kcal +/- 500, with saturated fat about 14% of calories per day. Comparisons between parents and childrens reports of food frequencies and portion sizes revealed the best correlations for beverages, bread-cereals-crackers, meat-fish-poultry, and mixed dishes. We conclude that preadolescent children are able to provide dietary intake data using electronic methods in a manner that compares favorably with their parents' written records.     

Trial of a mobile phone method for recording dietary intake in adults with type 2 diabetes: evaluation and implications for future applications

We evaluated a mobile phone application (Nutricam) for recording dietary intake. It allowed users to capture a photograph of food items before consumption and store a voice recording to explain the contents of the photograph. This information was then sent to a website where it was analysed by a dietitian. Ten adults with type 2 diabetes (BMI 24.1-47.9 kg/m(2)) recorded their intake over a three-day period using both Nutricam and a written food diary. Compared to the food diary, energy intake was under-recorded by 649 kJ (SD 810) using the mobile phone method. However, there was no trend in the difference between dietary assessment methods at levels of low or high energy intake. All subjects reported that the mobile phone system was easy to use. Six subjects found that the time taken to record using Nutricam was shorter than recording using the written diary, while two reported that it was about the same. The level of detail provided in the voice recording and food items obscured in photographs reduced the quality of the mobile phone records. Although some modifications to the mobile phone method will be necessary to improve the accuracy of self-reported intake, the system was considered an acceptable alternative to written records and has the potential to be used by adults with type 2 diabetes for monitoring dietary intake by a dietitian.     

The use of a self-administered questionnaire to assess diet four years in the past

The use of a mailed, self-administered, semiquantitative food frequency questionnaire to describe past dietary intake was evaluated in 1984 among a group of 150 Boston-area women who had completed four one-week diet records three to four years previously. Correlation coefficients comparing calorie-adjusted nutrient intakes computed from the questionnaire with those obtained from a compressed version of the questionnaire completed during diet record keeping ranged from 0.44 for total carbohydrate to 0.62 for vitamin C including supplements. Coefficients comparing calorie-adjusted nutrient intakes measured by questionnaire with those assessed by the diet records completed three to four years previously ranged from 0.28 for iron without supplements to 0.61 for total carbohydrate. An evaluation of the incremental contribution provided by several open-ended sections of the questionnaire to the estimation of nutrient intake suggested that in this population most of these items might be eliminated without material loss of information. These findings demonstrate that useful estimates of nutrient intake several years previously can be obtained by a relatively inexpensive, mailed, self-administered questionnaire.     

Validation and Reliability of the Alzheimer’s Disease-Commonwealth Scientific and Industrial Research Organisation Food Frequency Questionnaire

Accuracy in measuring intake of dietary constituents is an important issue in studies reporting the associations between diet and chronic diseases. We modified a Commonwealth Scientific and Industrial Research Organisation (CSIRO) food frequency questionnaire (FFQ) to include foods of interest in the field of Alzheimer’s disease (AD) research. The aim of the current study was to determine the reliability and validity of the AD-CSIROFFQ in 148 cognitively normal older adults. The AD-CSIROFFQ was completed before and after completion of a four-day weighed food record. Of the 508 food and beverage items reported, 309 had sufficient consumption levels for analysis of reliability. Of the 309 items, over 78% were significantly correlated between the two questionnaire administrations (Spearman’s rank correlations). We used two additional methods to assess absolute nutrient intake agreement between the AD-CSIROFFQ and the weighed food records (Pearson’s correlation coefficients and Bland–Altman plots) and quintile rankings to measure group level agreement. The adequate correlations observed between questionnaire responses suggest that the AD-CSIROFFQ is reliable. All nutrient intakes were acceptable for ranking of individuals on a group level, whilst the agreement levels with respect to the weighed food records for 11 of the 46 nutrients show validity in terms of their individual level absolute intake. The AD-CSIROFFQ makes an important contribution to the tools available for assessing usual dietary intake in groups of older adults with respect to AD research.     

Validity of a food frequency questionnaire varied by age and body mass index

BACKGROUND AND OBJECTIVE: The validity of food frequency questionnaires (FFQs) in measuring food consumption and nutrient intake has to be assessed. The objective of this study was to assess the validity of a 128-item FFQ in specific subgroups of Finnish adults. METHODS: The study included 294 subjects (137 men and 157 women). A 3-day food record was used as the reference method. RESULTS: The mean intake of all nutrients except alcohol was higher measured with the FFQ than with the food records. In general, the Pearson correlations for energy adjusted nutrients between the FFQ and the food records were higher in women than in men. The correlations ranged from 0.14 (retinol) to 0.66 (fiber and alcohol) in men, and from 0.20 (long-chain n-3 fatty acids) to 0.70 (alcohol) in women. The results in subgroups showed that measuring nutrient intakes is more difficult among younger (30-50 years) women and overweight men and women than among others. CONCLUSIONS: The study showed that the FFQ is a useful tool in epidemiologic studies in measuring the diet of Finnish adults given that the problems among specific subgroups are taken into account in interpretation.     

Measurement characteristics of the Women's Health Initiative food frequency questionnaire

PURPOSE: The Women's Health Initiative (WHI) is the largest research program ever initiated in the United States with a focus on diet and health. Therefore, it is important to understand and document the measurement characteristics of the key dietary assessment instrument: the WHI food frequency questionnaire (FFQ). METHODS: Data are from 113 women screened for participation in the WHI in 1995. We assessed bias and precision of the FFQ by comparing the intake of 30 nutrients estimated from the FFQ with means from four 24-hour dietary recalls and a 4-day food record. RESULTS: For most nutrients, means estimated by the FFQ were within 10% of the records or recalls. Precision, defined as the correlation between the FFQ and the records and recalls, was similar to other FFQs. Energy adjusted correlation coefficients ranged from 0.2 (vitamin B12) to 0.7 (magnesium) with a mean of 0.5. The correlation for percentage energy from fat (a key measure in WHI) was 0.6. Vitamin supplement use was common. For example, almost half of total vitamin E intake was obtained from supplements. Including supplemental vitamins and minerals increased micronutrient correlation coefficients, which ranged from 0.2 (thiamin) to 0.8 (vitamin E) with a mean of 0.6. CONCLUSIONS: The WHI FFQ produced nutrient estimate, that were similar to those obtained from short-term dietary recall and recording methods. Comparison of WHI FFQ nutrient intake measures to independent and unbiased measures, such as doubly labeled water estimates of energy expenditure, are needed to help address the validity of the FFQ in this population.