Acquiring correct eating habits is essential for promoting health among individuals and the population at large as well as for preventing a large number of pathologies that, to a greater or lesser extent, are nutrition relatedReference Hankey, Eley, Leslei, Hunter and Lean1–Reference Tuomilehto, Lindstrom, Eriksson, Valle, Hamalainen and Ilanne-Parikka4.
Multiple factors influence the adoption of eating habits, ranging from personal characteristics of the individual to those related to socio-cultural and psychological determinants. As such, societal food habits are determined to a large extent by cultural identification, traditions and belief systems. As evidenced by a number of studies, the influence of these factors on eating habits over the last few years has lead to an unbalanced nutritional profile in Spain. This has been associated with a significant number of pathologies with marked prevalence and mortality, such as cardiovascular disease, certain cancers, obesity, osteoporosis, iron-deficiency anaemia and dental cariesReference Young and Lee5–Reference García-Closas and Serra-Majem9.
Educational interventions targeting the improvement of food and nutrition problems affecting the population at large constitute the main strategy for nutrition-related chronic disease prevention and controlReference Hankey, Eley, Leslei, Hunter and Lean1.
In any and all cases, it is critical to understand why people behave as they do. Especially in relation to how, in accordance with their perceptions, the reasons for their actions are justified. It is important to identify what these reasons are before initiating interventions for dietary change.
In order to achieve behaviour changes, it is critical to understand the rationale behind the conduct and the socio-cultural factors that influence it. Knowing this information enables educational programmes to be designed so as to enhance motivation for participants to want to be healthy and how to achieve it. Therefore, it is opportune to carry out studies that evaluate knowledge, opinions and attitudes of the target population and to identify erroneous concepts, beliefs and attitudes with the aim of designing educational programmes that are adapted to participants’ needs. Moreover, this allows for tailored selection of the desired target behaviours to be modified or reinforced through the educational programme.
This study is derived from data obtained in the Catalan Nutrition Surveys of 1992–93 (ENCAT 1992–93) and 2002–03 (ENCAT 2002–03), both of which applied a similar methodology as a part of the Catalan Nutrition Monitoring system. The aim of this paper is to evaluate the modifications in three determinants of food behaviour, knowledge, opinions and attitudes, which occurred over a 10-year period as well as their distribution according to gender and age.
Methods
In ENCAT 1992–93Reference Serra Majem, Ribas Barba, García-Closas, Ramon, Salvador and Farran10 the random sample population consisted of inhabitants aged 6–75 years living in Catalan municipalities. The theoretical sample size was estimated to be 3000 subjects, assuming a 70% response rate. Data were collected via two interviews. All study participants were administered a general questionnaire that compiled information about socio-economic variables (profession, level of education, etc.) as well as the following: food habits, chronic disease control, smoking, physical activity, knowledge and opinions about nutrition. This was carried out in conjunction with the realisation of two diet-assessment questionnaires. Furthermore, several anthropometric measurements were taken (body weight, height, circumferences, etc.) under standardised conditions.
In ENCAT 2002–03Reference Serra Majem, Ribas Barba, Salvador Castell, Castell Abat, Román Viñas and Serra11 study participants were administered a comprehensive questionnaire that included many of the same questions used in the ENCAT 1992–93 studyReference Serra Majem, Ribas Barba, García-Closas, Ramon, Salvador and Farran10, and to which additional topics were added addressing, among others, food security and level of physical activity. The theoretical random sample population consisted of inhabitants aged 10–80 years living in Catalan municipalities, as this group comprised the population source of residents registered in the official census. As a participation rate of 70% was assumed, the theoretical sample size was estimated to be 3300 individuals (n expected=2310). The survey was carried out from March 2002 to June 2003 in the home of the subjects being interviewed by 22 previously trained dietitians.
Questionnaires
The same questionnaires were used in the 1992–93 and 2002–03 analyses. Only individuals aged 18–75 years answered the questionnaire about food attitudes and behaviour. Some questions were also answered by individuals aged 10 years and older.
The participants’ knowledge about food was evaluated by two questions. One of the questions consisted of answering (1) ‘true’, (2) ‘false’ or (3) ‘don’t know’ to a list of 14 foods whose consumption should be moderate or reduced to prevent high blood cholesterol. The second one consisted of rating a list of 24 foods according to their opinion that such foods had on their health: (1) being ‘harmful’, (2) ‘indifferent’, (3) ‘healthy’ and (4) being ‘very healthy’.
Preventive actions were determined by the following questions: ‘Have you ever had your (cholesterol level, blood pressure) checked?’; ‘Have you ever been weighed by a doctor or nurse?’; ‘Where do you usually weigh yourself?’ for which the following options were given: (1) ‘home’, (2) ‘pharmacy’, (3) ‘private office or public health center’, (4) ‘in other places’, (5) ‘I never weigh myself’; and lastly, ‘Do you take any (diet supplements, multivitamins, iodised salt or salt enriched with iodine and fluoride)?’.
Body image was assessed by the following questions: ‘Do you consider yourself as obese or overweight?’ Respondents who felt obese or overweight were asked: ‘Are you worried about the possible effects excess weight has on your health?’ giving them the following options: (1) ‘yes a lot’, (2) ‘quite worried’, (3) ‘not much’, (4) ‘not at all’. Two other questions were asked to the entire sample: ‘What do you consider the best method for losing weight?’ and the following options were given: (1) ‘eating less’, (2) ‘not drinking alcohol’, (3) ‘doing more exercise’, (4) ‘taking pills to reduce hunger’, (5) ‘others’; and ‘How has your weight been throughout your life?’ and the following options were given: (1) ‘stable’ and (2) ‘unstable’.
Dieting practices were evaluated as follows: ‘During the past 12 months, have you ever been on a diet?’ and ‘Are you currently following a diet?’ Those who had been on a diet were asked: ‘Who prescribed the diet?’ and the following options were given: (1) ‘a health professional – doctor, nurse, dietitian or pharmacist’, (2) ‘a friend’, (3) ‘a family member’, (4) ‘a non-health professional’, and (5) ‘others’. Those who were following a diet were asked: ‘Why are you currently on a diet?’ and the following options were given: (1) ‘diabetes’, (2) ‘hypertension’, (3) ‘excess weight’, (4) ‘cholesterol’ and (5) ‘others’; and ‘Who prescribed the diet?’ and the following answers were given: (1) ‘public health centre’ ‘doctor’, (2) ‘private doctor’, (3) ‘hospital’, (4) ‘others’.
Self-reported diabetes was determined with the following question: ‘Are you diabetic?’ and those who were diabetic were asked: ‘Which treatment are you following?’ and the followings answers were given: (1) ‘insulin’, (2) ‘diet’, (3) ‘oral hypoglycaemic agents’, (4) ‘diet and insulin’, (5) ‘diet and oral hypoglycaemic agents’, (6) ‘diet, insulin and oral hypoglycaemic agents’, (7) ‘no treatment being used’ and (8) ‘doesn’t know or no comment’.
Analysis of the dependent variables was realised by group comparisons. Data were compared by age and sex, using the χ 2 test for comparing proportions, and always based on the independence between variables and a 5% level of significance. The SPSS for Windows version 12.0 was used for the statistical analysis.
Results
In ENCAT 1992–93, 2361 individuals (1077 males and 1284 females) from 10 to 75 years participated in the interview, and in ENCAT 2002–03 a total of 2061 individuals (954 males and 1107 females) participated.
Tables 1–3 show results about subjects’ knowledge of how foods affect health and how certain foods affect serum levels of cholesterol for the period analysed.
Distribution of the population (%) based on opinions of how foods affect their health (ENCAT 1992–93 and ENCAT 2002–03)
Sample: Population aged 18–75 years.
ne – non-evaluated.
Distribution (%) of the population according to what foods they consider as very healthy (ENCAT 1992–93 and ENCAT 2002–03)
Sample: Population aged 18–75 years.
aP < 0.001, bP < 0.005, cP < 0.01, dP < 0.05, ne – non-evaluated.
Distribution of the population (%) that believe that certain foods should be reduced or moderated to prevent high blood cholesterol (ENCAT 1992–93 and ENCAT 2002–03)
aP < 0.001, bP < 0.005, cP < 0.01, dP < 0.05, ne – non-evaluated.
There was an improvement in knowledge (Table 1) of the sample population, especially with respect to blue fish (there was an increase in the percentage of people who thought it was a very healthy food, from 18% to 40%), olive oil (the percentage of people who thought it was very healthy increased from 21% to 45%) and wine (26% of people in 1992–93 thought it was healthy and the percentage increased to 45% in ENCAT 2002–03). Some food, such as pork, was not thought to be as harmful in 2002–03 (36% of people) as in 1992–93 (47%). Non-olive oils (sunflower seed oil and corn oil) were seen as more harmful in 2002–03 (from 9% to 18% for sunflower seed oil and from 11% to 27% for corn oil). Sugar also was thought to be more harmful in 2002–03 (from 16% to 19%).
In ENCAT 1992–93, most of the people thought that carrots (52% of the population), lettuce (48%) and white fish (37%) were very healthy foods, which was a common observation for all age groups and sexes (Table 2). In ENCAT 2002–03, lettuce (47%), carrots (46%), olive oil (45%) and blue fish (40%) were thought to be very healthy by most of the population. The notion that blue fish and olive oil were very healthy foods improved in all age groups and sexes. In addition the perception that wine was a healthy food increased in all age groups and genders. The perception that whole-grain bread was very healthy decreased among males and females, and only older individuals increased their awareness that this food was healthy over the period analysed.
Table 3 shows the perception of nutrition and its effect on plasma cholesterol levels. Cured meats and cold cuts (sausages), butter, baked foods and eggs were the identified foods that should be reduced or moderated to control blood cholesterol, in the 1992–93 and 2002–03 surveys. This perception was common for all age groups and sexes. Although some improvement was observed, a high percentage of individuals from 18 to 24 years thought that olive oil consumption should be reduced (49% of population in 1992–93 and 33% in 2002–03). In ENCAT 2002–03, 30% of the same age group thought that potato consumption should be reduced so as to prevent high blood cholesterol. Individuals also thought that bread should be reduced (39% of the population in 1992–93 and 31% in 2002–03). Sardine consumption should be reduced according to the oldest age group (18% of individuals in 1992–93 and 21% in 2002–03).
Table 4 shows trends in the preventive actions of the Catalan population. There was an increase in the proportion of individuals whose cholesterol had been checked. Nevertheless, in 2002–03, 34% of the population reported that they had never checked their cholesterol levels. There was an increase in the proportion of the population with previously registered blood pressure (91% in 2002–03) exams. The percentage of the sample that had ever been weighed by a nurse or a doctor increased from 63% in 1992–93 to 77% in 2002–03. Most of the population reported weighing themselves at home. Regarding the consumption of diet supplements or vitamins, there was an increase in the proportion of individuals who consumed diet supplements (from 6% to 10%), especially among females (from 6% to 13% of consumers), and who used iodised salt or salt enriched with iodine and fluoride (from 26% to 40%). A decrease in the consumers of multivitamins (from 10% to 8%) was observed.
Distribution (%) of the population according to the interviewer’s responses to various questions on preventive practices (ENCAT 1992–93 and ENCAT 2002–03)
Sample: Population aged 10–75 years.
aP < 0.001, bP < 0.005, cP < 0.05.
Table 5 shows trends for dieting habits and perceptions about excess weight. There was an increase in the percentage of the sample that had followed some kind of diet within the last 12 months (from 20% to 23%) and in the percentage of the population who were on a diet at the time the survey was conducted, especially among males (from 10% to 15%). There were few changes regarding the reason for being on a diet. Among males, there was an increase in the proportion of individuals dieting for losing weight and for having diabetes. Among females, excess weight was the main reason for dieting and the percentage increased over the period analysed (from 47% to 54%). The proportion of individuals who considered themselves as overweight or obese showed some modifications. Among males, the percentage of individuals who perceived having excess body weight increased (from 26% to 29%), whereas the percentage of females with such perceptions decreased (from 42% to 38%). Among those individuals who reported having excess weight, both males and females felt more concerned about how this excess could affect their health in the ENCAT 2002–03 (14% and 33% of individuals reported being very worried and quite worried about the possible effects that excess weight could have on their health in 1992–93, with increases to 15% and 39%, respectively, in 2002–03). The proportion of people who believed that doing more exercise was the best method for losing weight increased in the period analysed (from 35% to 43%), and the proportion of people who thought that eating less was the best method for weight loss was high in both surveys, especially among females.
Distribution (%) of the Catalan population according to dieting habits and perceptions about excess weight (ENCAT 1992–93 and ENCAT 2002–03)
Sample: Population aged 10–75 years.
aP < 0.001, bP < 0.005, cP < 0.05.
Table 6 shows the tendency for the self-reported prevalence of diabetes among the Catalan population. There was an increase in the prevalence of individuals with diabetes (from 3% to 4% of the population), particularly among males (from 3.4% to 4.5%). A decrease was observed in the proportion of individuals who, being diagnosed with diabetes, were not undergoing some form of treatment (from 14% to 6%), or were treated only with diet (from 42% to 13%) or with diet and oral hypoglycaemic medications (from 22% to 18%). On the other hand, there was an increase in the proportion of diabetic individuals who were treated with insulin (from 6% to 10%) and those who were treated with oral hypoglycaemic agents (from 2% to 31%).
Self reported prevalence of diabetes in the Catalan population (ENCAT 1992–93 and ENCAT 2002–03)
aP < 0.01, bP < 0.05.
OHA – oral hypoglycaemic agents.
Discussion
The difference between what the public is recommended to consume and what they actually eat can be accounted for, in part, by a lack of knowledge of what constitutes ‘healthy eating’ and dietary guidelines. On the other hand, it is becoming more and more evident that further research is needed on the new components outlined below of acquiring habits, which could facilitate the adoption in individuals and communities of positive health-enhancing food behaviour12:
• factors perceived to be the most influential on food choice,
• target population’s knowledge of what constitutes ‘healthy eating’,
• sources of information used by the population and the degree of confidence they have in them,
• perceived benefits and obstacles to attaining healthy eating habits,
• perception of need for modifying food habits,
• stages of change with regard to healthy eating.
Furthermore, it is fundamental for the adoption of healthy eating habits, given the diversity of factors that seem to be implicated in dietary change, that health promotion interventions take into account the participation of all sectors involved in achieving such change: consumers, supermarkets, social workers, health professionals, politicians, etc.
The attitudes, values and beliefs of a given population greatly influence what is learned, especially in concepts such as food, which is of utmost importance in the context of day-to-day living. This is widely accepted by various authors. For example, for DreyfusReference Dreyfus13, the attitudes, beliefs and values that have been developed without taking into account relevant scientific knowledge cannot be influenced in the absence of such information. Yet, this author also recognises that possessing scientific information in and of itself does not ensure the development of more receptive attitudes towards change.
RyderReference Ryder14 highlights the importance of attitudes, beliefs and values due to their role in guiding us in diverse and numerous situations in which science and technology are implicated in our lives. For AdamsReference Adams15, if we do not have the necessary knowledge base, the understanding of any given concept ends up being based not on objective truth but rather on what one believes to be true.
The evaluation of knowledge, attitudes and opinions about healthy eating in the population has been described in the literature mostly in terms of foods, food groups, nutrients (to limit the amount of fat, to eat less sugar, etc.), general terms (good or bad for you, unprocessed, natural) and diet varietyReference Povey, Conner, Sparks, James and Shepherd16. The methodology used for gathering information on people’s knowledge (for instance, the use of an open or a closed questionnaire) has some impact on the results. For example, in the Catalan Nutrition Survey a closed questionnaire was used, which may have influenced the population’s opinion, as they were not able to express in their own words their beliefs about food and health. For example, fruit was not included in the list of multiple choices. And it is precisely fruit that was not among the healthiest foods cited by the Spanish population in a Pan European Survey that evaluated the definition of healthy eating in the adult populationReference Martinez-Gonzalez, Lopez-Azpiazu, Kearney, Kearney, Gibney and Martinez17. As the authors cited, maybe there is a need to encourage fruit consumption in the Spanish population separating the message from the one of vegetables.
Some vegetables (lettuce and carrots), fish and olive oil were chosen as the healthiest foods in the two Catalan Nutrition Surveys. Fruit and vegetables were also the healthiest foods according to studies in the UKReference Povey, Conner, Sparks, James and Shepherd16, Reference Lake, Hyland, Rugg-Gunn, Wood, Mathers and Adamson18, in EuropeReference de Almeida, Graça, Afonso, Kearney and Gibney19 and in FinlandReference Niva20. In Catalonia, while in 1992–93 white fish was the type of fish considered most adequate for improving health, in 2002–03 blue fish was the one chosen. Olive oil also increased its rating. The results obtained from the 1992–93 Nutrition Survey in Catalonia served as the basis for developing certain educational activities targeting the general population in collaboration with the Department of Education and the Department of Health of the Catalan Government, which aimed to improve the population’s nutritional knowledge and to provide dietary advice21. The implementation of such campaigns encouraging the population to increase their knowledge and consumption of Mediterranean foods may have had some impact on the population as seen in the case of olive oil and blue fish, which were perceived as healthier choices in the 2002–03 survey. On the other hand, a pending issue may be to communicate the role that fibre has on health and the importance of increasing their intake, as the Catalan population, as in other Mediterranean countriesReference Martinez-Gonzalez, Lopez-Azpiazu, Kearney, Kearney, Gibney and Martinez17, lacks awareness of this relationship.
There is some controversy in the literature about the population’s belief regarding the effect excess meat consumption may have on their health. While some studies showed that as a healthy food meat instead of fish was the first choiceReference Paquette22, in other studies, such as the Pan European Survey, individuals from Mediterranean countries thought that eating less red meat was one of the options for following the healthiest diet. Individuals from central or northern countries in Europe did not share this viewReference Martínez-González, Holgado, Gibney, Kearney and Martinez23.
As reported in other studiesReference Paquette22, Reference Rappoport, Peters, Downey, McCann and Huff-Corzine24, no differences were found for food knowledge among males and females or across the age groups. However, there is a need to correct the misconceptions of younger individuals about the effect food has on their health, especially in light of this group’s potential to transform into a future chronic disease burden. The fact that this cohort is not able to identify the correct role of certain foods such as bread or potatoes, which form the foundation of the majority of food guides the world over, or olive oil, the key food of the Mediterranean diet, shows that there is still much work to be done.
One of the objectives of the periodic Health Plans for Catalonia25–27 was to evaluate the introduction of preventive actions to combat the principal prevalent chronic diseases in the Catalan health care system. Some specific objectives were to evaluate the degree of detection, treatment and follow up that health professionals conducted for certain cardiovascular risk factors such as blood cholesterol levels and glycaemia, body weight and blood pressure. The evaluation of the trends in Catalonia targeting primary prevention of certain risk factors showed an improvement in the degree of preventive actions. Nevertheless, a high percentage of the population reported that they had never checked their serum cholesterol levels or had never been weighed by a health professional. The prevalence of self-reported diabetes has increased, which might be a consequence of an increase in its prevalence or in the preventive actions, with an increase in the number of individuals that had ever checked their glucose levels. What is encouraging is the observed decrease in the number of non-treated diabetic individuals during the period analysed.
Catalan males’ self-perception as being overweight or obese has increased and, as such, the feeling that this excess weight may have some negative effect on their health. This awareness is encouraging, keeping in mind that the prevalence of obesity among males has increased in the two Surveys analysed. Females have improved in the perception of their body image, in accordance with the stabilisation of the prevalence of overweight and obesity in this cohort. The International Health and Behaviour Survey showed that 45% of females considered themselves as overweight (and 25% of males). In the same study, 51% of females and 21% of males were dieting to lose weightReference Wardle, Haase and Steptoe28. Dieting was more prevalent among women in all the countries that participated in the study. This was also true for the UK, where a population-based survey showed that 21% of males and 36% of females were trying to lose weightReference Wardle and Johnson29, and in the USReference Weiss, Galuska, Khan and Serdula30, where data from the 2001–02 NHANES showed that 34% of males and 48% of females had been trying to lose weight in the previous 12 months. In Catalonia, such differences among sexes were not reported and the prevalence in women was much lower, perhaps due to a sample that included individuals from all age groups. Although there have been some changes in the period analysed, males perceived that exercising was the best method to lose weight while females still relied on eating less as the best weight loss method. In fact, the primary reason for Catalan females to be on a diet was to lose weight, as also reported in studies from AustraliaReference Germov and Williams31 and the USReference Devine and Olson32. Most of the literature shows that when men diet, they use exercise as a tool to increase energy expenditure apart from eating lessReference Davy, Benes and Driskell33.
The Seven Countries StudyReference Keys, Menotti, Karvonen, Aravanis, Blackburn and Buzina34 demonstrated that the traditional Mediterranean diet had been protecting the health of the Mediterranean countries since the early 1960s, even when the population was unaware of its effect on their health. Unfortunately, this dietary pattern has undergone certain modifications and the adherence to such a pattern has decreased in certain Mediterranean countries. In this context, the more the population knows about healthy eating, the better the chances of correcting this trend. The increasing prevalence of overweight and obesity in SpainReference Aranceta, Perez Rodrigo, Serra Majem, Ribas Barba, Quiles Izquierdo and Vioque35 prompted the corresponding authorities to develop the Strategy for Nutrition, Physical Activity and the Prevention of Obesity (NAOS)Reference Neira and de Onis36, a project targeting the general population that involves multiple stakeholders with the aim of improving the diet and increasing the physical activity habits of the population. The project started in 2005 and is still ongoing. The future evaluations of knowledge, opinions and attitudes of the population will provide further insight into the success of this comprehensive nutrition policy.
Acknowledgements
Sources of funding: This work was made possible by financing from the General Division of Public Health of the Generalitat of Catalonia’s Department of Health, through a research agreement with the Fundación para la Investigación Nutricional (Nutrition Research Foundation).
Conflict of interest declaration: None of the authors had any conflicts of interest in connection with this study.
Authorship responsibilities: LSM was director of the study, was responsible of the interpretation of data and the writing of the paper, BRV revised the paper providing expert advice on data interpretation and in the discussion of the paper, GS participated in the study concept and design, LRB was responsible of the statistical analysis and revised the paper providing expert advice on data interpretation, JN provided expert advice on data interpretation and contributed to editing the paper, CC participated in the study concept and design and revised the paper providing expert advice on data interpretation, CC provided expert advice in the discussion of the paper.
Guarantor: Lluís Serra-Majem.
Acknowledgements: Special acknowledgement is made to all those persons who were interviewed, and whose collaboration made the realisation of these surveys possible.
Research Group on the Evaluation and Monitoring of the Nutritional Status in the Catalan Population: Lluís Serra-Majem, Director (University of Las Palmas de Gran Canaria); Lourdes Ribas-Barba, Coordinator (FIN – Nutrition Research Foundation, Barcelona Science Park); Gemma Salvador (Generalitat of Catalonia); Conxa Castell (Generalitat of Catalonia); Blanca Román – Viñas (FIN, Barcelona Science Park); Jaume Serra (Generalitat of Catalonia); Lluís Jover (University of Barcelona); Ricard Tresserras (Generalitat of Catalonia); Blanca Raidó (FIN, Barcelona Science Park); Andreu Farran (CESNID, University of Barcelona); Joy Ngo (FIN, Barcelona Science Park); Mari Cruz Pastor (Hospital Germans Trias i Pujol, Badalona); Lluís Salleras (University of Barcelona); and Carmen Cabezas, Josep Lluís Taberner, Salvi Juncà, Josep Maria Aragay, Eulàlia Roure, Gonçal Lloveras Vallès († 2003), Antoni Plasencia (Generalitat of Catalonia).
