Abstracts

Introduction

The assessment of individuals' dietary patterns is considered to be an important procedure to identify early nutritional status changes which may help prevent the emergence of diseases (1)1  Gibson RS. Principles of nutritional assessment. 2nd Ed. New York: Oxford University Press; 2005.. However, the detection of associations between food intake and the risk of diseases in population studies may be limited by the difficulty in measuring intake accurately. Data from studies using the doubly labeled water (DLW) technique have shown that some individuals (2)2  Schoeller DA. Limitations in the assessment of dietary energy intake by self-reported. Metabolism 1995; 44(2 Suppl 2):18-22. tend to underreport energy intake (EI). In general, EI underreporting increases with increasing age (3)3  Livingstone MB, Prentice AM, Coward WA, Strain JJ, Black AE, Davies PSW, et al. Validation of estimates of energy intake by weighed dietary record and diet history in children and adolescents. Am J Clin Nutr 1992; 56:29-35., is higher in women than in men and is more prevalent among overweight and obese individuals (4)4  Rodrigues AE, Marostegan PF, Mancini MC, Dalcanale L, Melo ME, Cercato C, et al. Analysis of resting metabolic rate evaluated by indirect calorimetry in obese women with low and high caloric intake. Arq Bras Endocrinol Metab 2008; 52:76-84. ^, (5)5  Souza DR, Anjos LA, Wahrlich V, Vasconcellos MTL, Machado JM. Ingestão alimentar e balanço energético da população adulta de Niterói, Rio de Janeiro, Brasil: resultados da Pesquisa de Nutrição, Atividade Física e Saúde (PNAFS). Cad Saúde Pública 2010; 26:879-90.. According to Goldberg et al. (6)6  Goldberg GR, Black AE, Jebb AS, Cole TJ, Murgatroyd PR, Coward WA, et al. Critical evaluation of energy intake data using fundamental principles of energy intake physiology: 1. Derivation of cut-off limits to identify under-recording. Eur J Clin Nutr 1991; 45:569-81., the ratio between EI and the basal metabolic rate (BMR) can be used to establish criteria for under and over reporting of EI. Mean values of EI below 1.35 times the BMR in individuals with stable body mass can serve as the cutoff point for detecting EI underreporting because it would be statistically unlikely that such a value would represent the usual intake. The cutoff value may, however, be different depending on the number of subjects being assessed, the number of days of EI assessment, the nutritional status and whether BMR is measured or predicted (6)6  Goldberg GR, Black AE, Jebb AS, Cole TJ, Murgatroyd PR, Coward WA, et al. Critical evaluation of energy intake data using fundamental principles of energy intake physiology: 1. Derivation of cut-off limits to identify under-recording. Eur J Clin Nutr 1991; 45:569-81. ^, (7)7  Briefel RR, McDowell MA, Alaimo K, Caughman CR, Bischof AL, Carroll MD, et al. Total energy intake of the US population: the third National Health and Nutrition Examination Survey, 1988-1991. Am J Clin Nutr1995; 62(5 Suppl):1072S-80S. ^, (8)8  Anjos LA, Souza DR, Rossato SL. Challenges in food intake assessment in population studies. Rev Nutr 2009; 22:151-61..

The problems with the numerator, estimated EI, have been documented extensively in the literature (1)1  Gibson RS. Principles of nutritional assessment. 2nd Ed. New York: Oxford University Press; 2005.. However, little attention has been given to the denominator. BMR is important not only in the assessment of the validity of EI information in population studies but also in the determination of the energy requirements of populations and in the expression of physical activity levels (9)9  Food and Agriculture Organization; World Health Organization. Human energy requirements. Report of a Joint FAO/WHO/UNU Expert Consultation. Rome: Food and Agriculture Organization; 2004. (Food and Nutrition Technical Report Series, 1).. Since it is not routinely measured, BMR is estimated by predictive equations (9)9  Food and Agriculture Organization; World Health Organization. Human energy requirements. Report of a Joint FAO/WHO/UNU Expert Consultation. Rome: Food and Agriculture Organization; 2004. (Food and Nutrition Technical Report Series, 1). ^, (10)10  Schofield WN. Predicting basal metabolic rate, new standards and review of previous work. Hum Nutr Clin Nutr 1985; 39 Suppl 1:5-41., but some studies have shown that these equations overestimate BMR in Brazilians living in the country (11)11  Anjos LA, Wahrlich V, Vasconcellos MTL. BMR in a Brazilian adult probability sample: the Nutrition, Physical Activity and Health Survey. Public Health Nutr 2014; 17:853-60. and abroad (12)12  Wahrlich V, Anjos LA, Teixeira TM. Basal metabolic rate: validation of a population-specific equation for Brazilians. Ann Nutr Metab 2013; 63 Suppl 1:1039.. A recent report has documented the inadequacy of the Food and Agriculture Organization/World Health Organization (FAO/WHO) recommended BMR equations (9)9  Food and Agriculture Organization; World Health Organization. Human energy requirements. Report of a Joint FAO/WHO/UNU Expert Consultation. Rome: Food and Agriculture Organization; 2004. (Food and Nutrition Technical Report Series, 1). ^, (10)10  Schofield WN. Predicting basal metabolic rate, new standards and review of previous work. Hum Nutr Clin Nutr 1985; 39 Suppl 1:5-41. in a probability sample of adults from Niterói, Rio de Janeiro State, Brazil (11)11  Anjos LA, Wahrlich V, Vasconcellos MTL. BMR in a Brazilian adult probability sample: the Nutrition, Physical Activity and Health Survey. Public Health Nutr 2014; 17:853-60.. Predicted BMR was significantly higher than measured BMR in men and women of all ages, leading the authors to develop (11)11  Anjos LA, Wahrlich V, Vasconcellos MTL. BMR in a Brazilian adult probability sample: the Nutrition, Physical Activity and Health Survey. Public Health Nutr 2014; 17:853-60. and validate (12)12  Wahrlich V, Anjos LA, Teixeira TM. Basal metabolic rate: validation of a population-specific equation for Brazilians. Ann Nutr Metab 2013; 63 Suppl 1:1039. equations to estimate BMR for the adult population of Niterói. Thus, reliable BMR information is crucial when assessing EI in population studies. To this end, the purpose of the present study was to identify EI underreporting using the EI/BMR ratio based on the BMR estimated using internationally recommended and Brazilian-specific predictive equations, according to the age and nutritional status of the adult population of Niterói. The hypothesis was that the frequency of underreporting would be lower when population-specific BMR equations were used in the analysis.

Materials and methods

The Nutrition, Physical Activity and Health Survey (PNAFS) was a household survey for which a probability sample of adults (≥ 20 years of age) living in the city of Niterói, was designed in three stages (5)5  Souza DR, Anjos LA, Wahrlich V, Vasconcellos MTL, Machado JM. Ingestão alimentar e balanço energético da população adulta de Niterói, Rio de Janeiro, Brasil: resultados da Pesquisa de Nutrição, Atividade Física e Saúde (PNAFS). Cad Saúde Pública 2010; 26:879-90. ^, (13)13  Bossan FM, Anjos LA, Vasconcellos MTL, Wahrlich V. Nutritional status of the adult population in Niterói, Rio de Janeiro, Brazil: the Nutrition, Physical Activity, and Health Survey. Cad Saúde Pública2007; 23:1867-76. ^, (14)14  Anjos LA, Barbosa TBC, Wahrlich V, Vasconcellos MTL. Padrão de atividade física em um dia típico de adultos de Niterói, Rio de Janeiro, Brasil: resultados da Pesquisa de Nutrição, Atividade Física e Saúde (PNAFS). Cad Saúde Pública2012; 28:1893-902.. In the first stage, 110 census enumeration areas (CEAs) were selected with a probability proportional to the number of household dwellings from an ordered list according to the average household income. This procedure allowed an implicit income stratification of the CEAs. In the second stage, for each selected CEA, 80 households were selected with equal probability to define a basic list used in the inverse sampling procedure (15)15  Haldane JB. On a method of estimating frequencies. Biometrika 1945; 33:222-5. similar to that of the World Health Survey in Brazil (16)16  Vasconcellos MTL, Silva PLN, Szwarcwald CL. Sampling design for the World Health Survey in Brazil. Cad Saúde Pública2005; 21 Suppl 1:S89-99.. In the third stage, for each interviewed household, an adult was selected to participate in the study with equal probability among all adults in the household. To be eligible, the adult had to be free of any cardiac or metabolic condition, under no medication that could alter food intake or metabolism, be under no restricted diet or be pregnant.

A first visit was conducted to each selected household to explain the purpose of the study, to obtain written consent and to schedule the beginning of data collection. In the morning of the schedule day, a trained nutritionist conducted a 24 hour dietary recall (24hR) (5)5  Souza DR, Anjos LA, Wahrlich V, Vasconcellos MTL, Machado JM. Ingestão alimentar e balanço energético da população adulta de Niterói, Rio de Janeiro, Brasil: resultados da Pesquisa de Nutrição, Atividade Física e Saúde (PNAFS). Cad Saúde Pública 2010; 26:879-90.. The interviews were balanced on all weekdays in order to represent the mean intake of the population (1)1  Gibson RS. Principles of nutritional assessment. 2nd Ed. New York: Oxford University Press; 2005..

A food photograph album (17)17  Zabotto CB, Viana RPT, Gil MF. Registro fotográfico para inquéritos dietéticos: utensílios e porções. Campinas: Universidade Estadual de Campinas/Goiânia: Universidade Federal de Goiás; 1996. was used to help the subject estimate food portion sizes. If the food item was not present in the album, the size was estimated from other food items present in the album. Each reported food item was converted to grams based on the published food weights of the food photograph album. Foods or preparations reported in household measures were converted to grams using a table for Brazilian kitchenware measures (18)18  Pinheiro ABV, Lacerda EMA, Benzecry EH, Gomes MCS, Costa VM. Tabela para avaliação de consumo alimentar em medidas caseiras. 5ª Ed. Rio de Janeiro: Editora Atheneu; 1996.. The size/weight of foods or preparations eaten outside the house was obtained directly from the provider/manufacturer. The reported foods or preparations were converted to energy and macronutrients using computer software developed for the Brazilian cuisine (NutWin; Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil). For foods or preparations not present in the program, tables of chemical composition of foods were used (19)19  Instituto Brasileiro de Geografia e Estatística. Estudo Nacional de Despesa Familiar - ENDEF. Tabelas de composição de alimentos. 3ª Ed. Rio de Janeiro: Instituto Brasileiro de Geografia e Estatística; 1985. ^, (20)20  Ulene A. The Nutribase nutrition facts desk reference: the single encyclopedic source for the most complete, up-to-date and comprehensive collection of food values. New York: Avery Publishing Group; 1995..

Anthropometric measurements were done in the household with the subject barefoot and with as little clothing as possible, usually in the morning. Body mass was measured once with electronic calibrated scales (Soehnle, Murrhardt, Germany) to the nearest 0.1kg. Stature was measured in duplicate with a portable stadiometer (Seca, Birmingham, UK) attached to a wall. Body mass index (BMI) was calculated as body mass divided by squared stature. Nutritional status was determined according to the WHO classification ²¹ using the BMI categories (kg.m^-2): underweight (< 18.5), adequate (18.5-24.9), overweight (25-29.9), and obese (≥ 30). BMR for each individual was estimated by predictive equations recommended for international use (9)9  Food and Agriculture Organization; World Health Organization. Human energy requirements. Report of a Joint FAO/WHO/UNU Expert Consultation. Rome: Food and Agriculture Organization; 2004. (Food and Nutrition Technical Report Series, 1). ^, (10)10  Schofield WN. Predicting basal metabolic rate, new standards and review of previous work. Hum Nutr Clin Nutr 1985; 39 Suppl 1:5-41. and the ones developed in a sub-sample of the PNAFS (11)11  Anjos LA, Wahrlich V, Vasconcellos MTL. BMR in a Brazilian adult probability sample: the Nutrition, Physical Activity and Health Survey. Public Health Nutr 2014; 17:853-60.. The equations are BMR = 9.99(body mass) + 7.14(stature) - 2.79(age in years) - 450.5 for males and; BMR = 8.95(body mass) + 8.87(stature) - 0.70(age in years) - 814.3 for females. EI underreporting was based on the EI/BMR ratio of 1.53 in accordance with the criterion suggested by Goldberg et al. (6)6  Goldberg GR, Black AE, Jebb AS, Cole TJ, Murgatroyd PR, Coward WA, et al. Critical evaluation of energy intake data using fundamental principles of energy intake physiology: 1. Derivation of cut-off limits to identify under-recording. Eur J Clin Nutr 1991; 45:569-81..

Of the 1,760 subjects selected, it was not possible to calculate the EI of 34 individuals due to fasting (2 subjects), and incompleteness of the 24hR. Thus, the final sample was composed of 1,726 individuals (1,202 women). Statistical weighting of the data allowed a representation of a total of 324,671 adults from the Niterói population (145,886 men and 178,785 women). Descriptive statistics (mean, standard error - SE and 95% confidence intervals - 95%CI) were computed using the surveymeans and surveyfreq procedures of SAS (SAS Inst., Cary, USA) which adequately address complex sample designs, using calibrated weights. The significance of the differences of EI, BMR and EI/BMR between age and nutritional status categories were identified when the 95%CI did not overlap.

The Ethics Research Committee of the Sergio Arouca National School of Public Health, Oswaldo Cruz Foundation approved all research procedures in accordance with the Declaration of Helsinki for protection of human subjects from research risks.

Results

Mean (± SE) age was 45.3 ± 0.6 years for women and 43.0 ± 0.7 years for men and mean BMI was 25.5 ± 0.1kg.m^-2 and 25.4 ± 0.2kg.m^-2, respectively (Table 1). Prevalence of underweight was low (2.9% and 2.1% in women and men, respectively) but overweight (32% and 34.4%) and obesity (15.1% and 13.8%) were highly prevalent.

EI was 1,570.9 ± 24.1kcal.day^-1 in women and 2,188.8 ± 46.1kcal.day^-1 in men. BMR was significantly higher when the Schofield equation was used for estimates (1,512.2 ± 7.1kcal.day^-1; 95%CI: 1,498.2; 1,526.3kcal.day^-1) compared with the Brazilian equations (1,256.1 ± 5.8kcal.day^-1; 95%CI: 1,244.6; 1,267.6kcal.day^-1) in the population as a whole and in both the female and male population separately (Table 1), representing a difference of approximately 19% and 21%, respectively.

The results of BMR and EI/BMR according to the age of men and women are presented in Table 2. The highest EI was observed in the 20-30 year-old group both in women and men and the lowest in the ≥ 60 year-old group. There was a progressive and significant decline in EI with increasing age, a phenomenon more evident and pronounced among men (Figure 1a). EI increased with increasing BMI in men but decreased in women (Figure 1b).

Among men, BMR decreased with increasing age, a fact not so clearly identified in women, although BMR was significantly different between the youngest and oldest age groups for both sexes. Since BMR estimated by the Brazilian equations was always lower than the Schofield equations, the mean EI/BMR ratio was always higher when it was calculated using BMR estimated using the Brazilian equations. The lowest EI/BMR ratios calculated with BMR predicted by the Schofield's equation were found in the 50-60 year age bracket, with values of 1.06 ± 0.03 and 1.19 ± 0.05 for women and men respectively (Table 2).

Table 3 presents the results of BMR and EI/BMR according to the nutritional status of the female and male population. The mean EI/BMR ratio decreased with increasing BMI, a phenomenon more evident in the female population, in whom the EI/BMR ratio of the lowest BMI was significantly higher than the value of the highest BMI (Table 3).

When the EI/BMR ratio was calculated with BMR estimated by the Schofield equations, underreporting was 80.4% (95%CI: 77.8; 83.0) and 72.6% (95%CI: 66.1; 77.2) for women and men respectively. The same values calculated with the Brazilian equations were 66.1% (95%CI: 62.9; 69.3) and 55.6% (9%%CI: 50.9; 60.2). Underreporting was higher in overweight/obese individuals in comparison to underweight subjects, irrespective of the equation used. Table 4 presents the percentage of individuals who underreported EI according to age, nutritional status and sex. With the exceptions of the ≥ 60 year-old group and the underweight groups, EI underreporting was significantly lower using BMR estimated by the Brazilian equations in women.

Discussion

Assessment of the population's EI is important in the context of societies facing demographic transitional changes. The results of this study confirm, for the adult population of Niterói, the nutritional profile documented for the Brazilian population in the latest Household Budget Survey (22)22  Instituto Brasileiro de Geografia e Estatística. Antropometria e estado nutricional de crianças, adolescentes e adultos no Brasil: Pesquisa de Orçamentos Familiares 2008-2009. Rio de Janeiro: Instituto Brasileiro de Geografia e Estatística; 2010.: low prevalence of underweight and high prevalence of overweight and obesity.

Dietary data of the adult population of Niterói showed that older male and female individuals report eating less, results that confirm the data found in the estimated EI of the population as a whole (1,490 and 1,795kcal.day^-1 for the female and male population, respectively), and in the southeastern region where Niterói is located, in the most recent Household Budget Survey (23)23  Instituto Brasileiro de Geografia e Estatística. Análise do consumo alimentar pessoal no Brasil: Pesquisa de Orçamentos Familiares 2008-2009. Rio de Janeiro: Instituto Brasileiro de Geografia e Estatística; 2011..

Since the determination of energy requirements is given by the estimation of energy expenditure calculated, in most cases, as the product of BMR and physical activity level ⁹, overestimation of energy requirements becomes very critical in obese individuals. Because BMR is rarely measured in clinical or epidemiological studies, predictive equations based on body mass and specific age groups are frequently used (9)9  Food and Agriculture Organization; World Health Organization. Human energy requirements. Report of a Joint FAO/WHO/UNU Expert Consultation. Rome: Food and Agriculture Organization; 2004. (Food and Nutrition Technical Report Series, 1).. It has been well documented that these equations overestimate BMR (11)11  Anjos LA, Wahrlich V, Vasconcellos MTL. BMR in a Brazilian adult probability sample: the Nutrition, Physical Activity and Health Survey. Public Health Nutr 2014; 17:853-60. ^, (12)12  Wahrlich V, Anjos LA, Teixeira TM. Basal metabolic rate: validation of a population-specific equation for Brazilians. Ann Nutr Metab 2013; 63 Suppl 1:1039.. In fact, BMR values calculated by the equation proposed by Anjos et al. (11)11  Anjos LA, Wahrlich V, Vasconcellos MTL. BMR in a Brazilian adult probability sample: the Nutrition, Physical Activity and Health Survey. Public Health Nutr 2014; 17:853-60. and validated by Wahrlich et al. (12)12  Wahrlich V, Anjos LA, Teixeira TM. Basal metabolic rate: validation of a population-specific equation for Brazilians. Ann Nutr Metab 2013; 63 Suppl 1:1039., specific for the population of Niterói, show that the equations recommended for international use significantly overestimate BMR, confirming the results documented in segments of the Brazilian population living in the country (11)11  Anjos LA, Wahrlich V, Vasconcellos MTL. BMR in a Brazilian adult probability sample: the Nutrition, Physical Activity and Health Survey. Public Health Nutr 2014; 17:853-60. and abroad (24)24  Wahrlich V, Anjos LA, Going SB, Lohman TG. Basal metabolic rate of Brazilians living in the Southwestern United States. Eur J Clin Nutr2007; 61:289-93.. The results also showed differences in BMR when stratified by age, sex and nutritional status (BMI), factors that directly influence BMR (25)25  Heitmann BL, Lissner L. Dietary underreporting by obese individuals: is it specific or non specific? BMJ 1995; 311:986-9..

In individuals with excess body mass, negative energy balance (EI-energy expenditure) is often observed when energy expenditure is estimated by BMR x physical activity level, a situation that is not compatible with their nutritional status (5)5  Souza DR, Anjos LA, Wahrlich V, Vasconcellos MTL, Machado JM. Ingestão alimentar e balanço energético da população adulta de Niterói, Rio de Janeiro, Brasil: resultados da Pesquisa de Nutrição, Atividade Física e Saúde (PNAFS). Cad Saúde Pública 2010; 26:879-90.. There are some basic methodological problems with the generation of such data, which may compromise interpretation. First, several studies of food intake in individuals with excess body mass seem to indicate that this segment of the population underreports EI (4)4  Rodrigues AE, Marostegan PF, Mancini MC, Dalcanale L, Melo ME, Cercato C, et al. Analysis of resting metabolic rate evaluated by indirect calorimetry in obese women with low and high caloric intake. Arq Bras Endocrinol Metab 2008; 52:76-84. ^, (26)26  Johansson L, Solvoll K, Bjorneboe GEA, Drevon CA. Under- and overreporting of energy intake related to weight status and lifestyle in a nationwide sample. Am J Clin Nutr1998; 68:266-74. ^, (27)27  Rennie KL, Coward A, Jebb SA. Estimating under-reporting of energy intake in dietary surveys using an individualised method. Br J Nutr 2007; 97:1169-76. ^, (28)28  Black AE, Cole TJ. Within- and between-subject variation in energy expenditure measured by the doubly-labelled water technique: implications for validating reported dietary energy intake. Eur J Clin Nutr2000; 54:386-94.. One possibility to identify EI under (or over) reporting is the calculation of the EI/BMR ratio. The cutoff values for the ratio were developed assuming that energy requirement equals EI for sedentary individuals whose body mass remains stable.

In the present study, the EI/BMR ratio was lower in overweight and obese individuals, with significant differences in each BMI category, confirming data from other studies (4)4  Rodrigues AE, Marostegan PF, Mancini MC, Dalcanale L, Melo ME, Cercato C, et al. Analysis of resting metabolic rate evaluated by indirect calorimetry in obese women with low and high caloric intake. Arq Bras Endocrinol Metab 2008; 52:76-84. ^, (6)6  Goldberg GR, Black AE, Jebb AS, Cole TJ, Murgatroyd PR, Coward WA, et al. Critical evaluation of energy intake data using fundamental principles of energy intake physiology: 1. Derivation of cut-off limits to identify under-recording. Eur J Clin Nutr 1991; 45:569-81. ^, (26)26  Johansson L, Solvoll K, Bjorneboe GEA, Drevon CA. Under- and overreporting of energy intake related to weight status and lifestyle in a nationwide sample. Am J Clin Nutr1998; 68:266-74. ^, (27)27  Rennie KL, Coward A, Jebb SA. Estimating under-reporting of energy intake in dietary surveys using an individualised method. Br J Nutr 2007; 97:1169-76. ^, (28)28  Black AE, Cole TJ. Within- and between-subject variation in energy expenditure measured by the doubly-labelled water technique: implications for validating reported dietary energy intake. Eur J Clin Nutr2000; 54:386-94. ^, (29)29  McGowan MJ, Harrington KE, Kiely M, Robson PJ, Livingstone MBE, Gibney MJ. An evaluation of energy intakes and the ratio of energy intake to estimated basal metabolic rate (EI/BMRest) in the North/South Ireland Food Consumption Survey. Public Health Nutr2008; 4:1043-50.. The EI/BMR ratio was close to 1 for obese individuals indicating an inadequate case of equality of EI and BMR. However, this has already been reported in the literature: in a sample of 215 middle-aged, low-income, low-literate Caribbean Latino population at risk of developing type 2 diabetes (78% were obese), mean EI/estimated BMR was 1.03 ± 0.37 and was lower in individuals with higher BMI (30)30  Olendzki BC, Ma Y, Hebert JR, Pagoto SL, Merriam PA, Rosal MC, et al. Underreporting of energy intake and associated factors in a Latino population at risk of developing type 2 diabetes. J Am Diet Assoc 2008; 108:1003-8.. The EI/BMR values of the American population investigated in the various waves of the National Health and Nutrition Examination Survey (NHANES) since 1971 have been shown to be 1.31 and 1.19 for men and women, respectively (31)31  Archer E, Hand GA, Blair SN. Validity of U.S. nutritional surveillance: National Health and Nutrition Examination Survey caloric energy intake data, 1971-2010. PLoS One 2013; 8:e76632.. This shows how difficult it is to trust self-report EI measurements especially if BMR (or energy expenditure) is not measured or adequately estimated.

It is important to highlight that the EI/BMR values were always lower when the population-specific BMR equations were used in the present study. This is due to the difference in BMR estimated by the two sets of equations (≈ 20%). It is recognized that BMR is overestimated by general prediction equations in some populations (9)9  Food and Agriculture Organization; World Health Organization. Human energy requirements. Report of a Joint FAO/WHO/UNU Expert Consultation. Rome: Food and Agriculture Organization; 2004. (Food and Nutrition Technical Report Series, 1). ^, (11)11  Anjos LA, Wahrlich V, Vasconcellos MTL. BMR in a Brazilian adult probability sample: the Nutrition, Physical Activity and Health Survey. Public Health Nutr 2014; 17:853-60.. EI/BMR data from the third phase of the NHANES decreased with increasing BMI (32)32  Briefel RB, Sempos CT, McDdowell MA, Chien SCY, Alaimo K. Dietary methods research in the third National Health and Nutrition Examination Survey: underreporting of energy intake. Am J Clin Nutr1997; 65(4 Suppl):1203S-9S., which may have been due to the lower value of the numerator (underreporting) and overestimation of the denominator, overestimation of BMR based on the increasing values of body mass (8)8  Anjos LA, Souza DR, Rossato SL. Challenges in food intake assessment in population studies. Rev Nutr 2009; 22:151-61.. Individuals with greater body mass expend more energy to move their body mass, meaning that their energy intake will have to be higher to maintain their greater body mass, a fact documented in the publications on energy requirements by the Institute of Medicine (33)33  Institute of Medicine. Dietary reference intakes for energy, carbohydrate, fiber, fat, fatty acids, protein, and amino acids. Part 1. Washington DC: National Academy Press; 2002. and FAO/WHO (9)9  Food and Agriculture Organization; World Health Organization. Human energy requirements. Report of a Joint FAO/WHO/UNU Expert Consultation. Rome: Food and Agriculture Organization; 2004. (Food and Nutrition Technical Report Series, 1).. The fact that BMR is higher in individuals with higher body mass may explain the data found in the adult population of Niterói, in whom the EI/BMR ratio was lower in subjects with higher BMI. Estimated energy expenditure in the same population (34)34  Anjos LA, Ferreira BCM, Vasconcellos MTL, Wahrlich V. Gasto energético em adultos do município de Niterói, Rio de Janeiro: resultados da Pesquisa de Nutrição, Atividade Física e Saúde - PNAFS. Ciênc Saúde Coletiva 2008; 13:1775-84. showed that as BMI increased energy expenditure also increased.

EI underreporting has been estimated to vary widely (10-45%) depending on age, sex and body composition (27)27  Rennie KL, Coward A, Jebb SA. Estimating under-reporting of energy intake in dietary surveys using an individualised method. Br J Nutr 2007; 97:1169-76. ^, (28)28  Black AE, Cole TJ. Within- and between-subject variation in energy expenditure measured by the doubly-labelled water technique: implications for validating reported dietary energy intake. Eur J Clin Nutr2000; 54:386-94. ^, (29)29  McGowan MJ, Harrington KE, Kiely M, Robson PJ, Livingstone MBE, Gibney MJ. An evaluation of energy intakes and the ratio of energy intake to estimated basal metabolic rate (EI/BMRest) in the North/South Ireland Food Consumption Survey. Public Health Nutr2008; 4:1043-50. ^, (35)35  Ferrari P, Slimani N, Ciampi A, Trichopoulou A, Naska A, Lauria C, et al. Evaluation of under- and overreporting of energy intake in the 24-hour diet recalls in the European Prospective Investigation into Cancer and Nutrition (EPIC). Public Health Nutr2002; 5:1329-45.. Underreporting increases with age (3)3  Livingstone MB, Prentice AM, Coward WA, Strain JJ, Black AE, Davies PSW, et al. Validation of estimates of energy intake by weighed dietary record and diet history in children and adolescents. Am J Clin Nutr 1992; 56:29-35., is higher in women and is more prevalent among overweight and obese individuals (4)4  Rodrigues AE, Marostegan PF, Mancini MC, Dalcanale L, Melo ME, Cercato C, et al. Analysis of resting metabolic rate evaluated by indirect calorimetry in obese women with low and high caloric intake. Arq Bras Endocrinol Metab 2008; 52:76-84. ^, (5)5  Souza DR, Anjos LA, Wahrlich V, Vasconcellos MTL, Machado JM. Ingestão alimentar e balanço energético da população adulta de Niterói, Rio de Janeiro, Brasil: resultados da Pesquisa de Nutrição, Atividade Física e Saúde (PNAFS). Cad Saúde Pública 2010; 26:879-90. ^, (25)25  Heitmann BL, Lissner L. Dietary underreporting by obese individuals: is it specific or non specific? BMJ 1995; 311:986-9.. The results of the present study confirm these findings. EI underreporting increased with increasing BMI. It is worth noting that except for underweight individuals, all age and nutritional status groups presented more than 50% of EI underreporting. Schoeller (2)2  Schoeller DA. Limitations in the assessment of dietary energy intake by self-reported. Metabolism 1995; 44(2 Suppl 2):18-22. has reported this as the usual level of underreporting found in energy expenditures studies using DLW. This technique can be used to identify EI underreporting if one assumes that the energy expenditure equals EI when body mass and composition are stable (29)29  McGowan MJ, Harrington KE, Kiely M, Robson PJ, Livingstone MBE, Gibney MJ. An evaluation of energy intakes and the ratio of energy intake to estimated basal metabolic rate (EI/BMRest) in the North/South Ireland Food Consumption Survey. Public Health Nutr2008; 4:1043-50.. However, the method is too costly to be used in large epidemiological studies. Thus, it is imperative that accurate estimation of BMR (preferably measured) be used in health-related nutrition studies to ascertain the quality of EI information and its associations.

The accurate estimate of dietary intake remains a challenge but the 24hR is still considered an adequate method to determine the EI of large samples of individuals when all days of the week are assessed (9)9  Food and Agriculture Organization; World Health Organization. Human energy requirements. Report of a Joint FAO/WHO/UNU Expert Consultation. Rome: Food and Agriculture Organization; 2004. (Food and Nutrition Technical Report Series, 1). despite the problems with memory, food size estimation and the food chemical composition tables. In the present study only one 24hR was obtained in a probability sample of adults in a household survey which might be considered a limitation. Because dietary intake of an individual is not constant from day to day, an understanding of the variability in food intake is required to estimate usual intake. Variability in food intake arises both because each individual differs in the types and amounts of food ingested from one day to the next (36)36  Hall KD, Heymsfield SB, Kemnitz JW, Klein S, Schoeller DA, Speakman JR. Energy balance and its components: implications for body weight regulation. Am J Clin Nutr2012; 95:989-94. ^, (37)37  Palaniappan U, Cue RI, Payette H, Gray-Donald K. Implications of day-to-day variability on measurements of usual food and nutrient intakes. J Nutr 2003; 133:232-5. and because individuals differ from each other in their food intakes (between- or inter-subject variability) (1)1  Gibson RS. Principles of nutritional assessment. 2nd Ed. New York: Oxford University Press; 2005.. Thus, the 24h dietary recall method is believed to represent the usual dietary intake of individuals when it is repeated in a number of days depending on the nutrient of interest (1)1  Gibson RS. Principles of nutritional assessment. 2nd Ed. New York: Oxford University Press; 2005.. However, a single 24hR can represent the mean intake of groups of individuals in dietary surveys given that all days of the week are assessed in a probability sample of the population (1)1  Gibson RS. Principles of nutritional assessment. 2nd Ed. New York: Oxford University Press; 2005. as was done in the present study. This procedure has been performed in large population surveys (7)7  Briefel RR, McDowell MA, Alaimo K, Caughman CR, Bischof AL, Carroll MD, et al. Total energy intake of the US population: the third National Health and Nutrition Examination Survey, 1988-1991. Am J Clin Nutr1995; 62(5 Suppl):1072S-80S..

Conclusion

The results of the present study confirm that EI is underreported, especially in individuals with excess body mass. It is crucial that BMR be adequately estimated when it is not possible to measure it if the purpose is to identify EI underreporting.

Acknowledgments

The study was supported by Fiocruz (PAPES III/2013, n. 250.139) and CNPq (n. 471172/2001-4 and n.475122/2003-8). L. A. Anjos received a research productivity grant from CNPq (n. 305399-2012-8).

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