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Abstract

Background:

Lifestyle in Western countries has significantly changed during recent decades. These and other factors have increased the prevalence of overweight and obesity, leading to a higher risk of noncommunicable diseases such as cardiovascular disease and cancer. A balanced diet has been shown to predict better health, so several public healthcare strategies aim to encourage “healthy” food choices.

Objectives:

To assess self-concept of knowledge about nutrition compared to factual knowledge and knowledge implementation in daily life.

Design:

Cross-sectional cohort study with a total of 524 Swiss women recruited, of which 447 women met the inclusion criteria for the final analysis.

Methods:

Main outcome measure: a self-constructed questionnaire was used to evaluate subjective and objective knowledge about healthy nutrition and its practical application. Subgroup analyses utilized Fisher’s test for categorical and Mann–Whitney-U test for metric/ordinal.

Results:

Most participants sourced their nutritional information predominantly from nonexperts. While the majority believed they were well-educated about nutrition, this self-assessment was only partially accurate. The “nutrition pyramid” concept was widely recognized, and correct assignment of food items to dominant macronutrient components was generally accurate. However, understanding of food category ranking by optimal daily intake and composing a healthy diet was lacking. Higher education levels correlated with better objective nutrition knowledge (p < 0.001), and normal-weight women were more likely than overweight/obese women to implement nutritional knowledge daily (p = 0.021). Apart from body mass index other bio-psycho-social factors were observed.

Conclusion:

Recent insights show that although women perceive themselves as knowledgeable about nutrition, there are significant gaps in their objective understanding. Higher education levels improve nutritional knowledge, and normal-weight women apply this knowledge more effectively. Thus, providing accessible, high-quality expert information on nutrition is essential.

Trial registration:

The study has been approved by the Cantonal Ethics Committee (registration number: 2018-00358).

Keywords

diet education females nutrition self-concept knowledge

Introduction

Lifestyle in Western countries has significantly changed during recent decades which, among other factors, has increased the prevalence of overweight/obesity. Both increase the risk to develop chronic noncommunicable diseases (NCD) such as cardiovascular disease and cancer while a balanced diet has been found to be a predictor of health.^1,2 Today, all NCDs make up about 80% of healthcare costs.³ Consequently, several public healthcare strategies by the Swiss Society for Nutrition have been developed to increase the likelihood of “healthy” food choices in the individual such as the food pyramid or the more recently emphasized plate model.^4,5 The Swiss food pyramid is based on general dietary recommendations and illustrates how to implement them. It visually represents a balanced diet, where foods at the lower levels are to be consumed in larger quantities and those at the upper levels in smaller quantities. The key to a balanced diet is the correct combination of foods in appropriate proportions.⁴ While the Swiss food pyramid illustrates general dietary recommendations and remains a valuable tool for understanding the broader framework of food group consumption, it has been increasingly supplemented by the plate model, which offers a more practical guide for composing balanced meals. The plate model demonstrates the optimal ratio of different food groups on a single plate, emphasizing portion sizes and mindful eating.⁴ The plate model, on the other hand, provides a practical guide for composing balanced meals. It demonstrates the optimal ratio of different food groups on a single plate. This model emphasizes the importance of portion sizes and encourages mindful eating.⁵

Understanding individual perceptions of nutrition knowledge, their alignment with objective knowledge, and the implementation of this knowledge in daily life is essential for effective health promotion efforts. The concept of self-concept of knowledge, actual knowledge, and knowledge implementation are pivotal in this context. According to previous research, individuals may inaccurately assess their own knowledge levels, leading to discrepancies between self-perceived knowledge about nutrition and actual factual understanding. This discrepancy can influence how individuals apply nutritional knowledge in their daily dietary practices.⁶

The aim of this cross-sectional cohort study in women was to assess the subjective knowledge about nutrition, compare it to their objective knowledge, and to evaluate the degree of knowledge implementation (and its barriers) in daily life. Furthermore, the impact of education, general interest in nutrition, body mass index (BMI), and language origin were evaluated.

Based on previous studies and literature reviews (PubMed^®, Medline^®, World Health Organization, Federal Office of Public Health and Statistics, and German Diabetes Society), six hypotheses were formulated: (1) less educated women know less about healthy nutrition,^7
–9 (2) overweight/obese women know less about healthy nutrition,⁹ (3) implementation of knowledge in daily life also relies on other factors than just factual knowledge,⁸ (4) despite possible cultural differences, language regions in Switzerland do not have an impact on knowledge about nutrition as the same information and food is available in the whole country,^4,5 (5) More general interest in nutrition is associated with more knowledge about healthy nutrition,¹⁰ (6) Most women believe to know more about nutrition than they do.¹¹

However, the study also aims to address significant knowledge gaps in women’s nutrition understanding, both nationally and potentially internationally. This clarification could guide more effective public health strategies and educational programs tailored to improve nutritional literacy among women, contributing to evidence-based interventions in nutritional health.

Methods

Study population

A total of 447 women participated in the study. Inclusion criteria required subjects to be 18 years of age, have Swiss nationality, and have sufficient language proficiency in German, French, Italian, or Romansh. Of the 329 participants who reported their BMI, 246 (75.5%) had a BMI below 25 kg/m², while 80 (24.5%) had a BMI of 25 kg/m² or higher, thus classified as overweight or obese.

Exclusion criteria included lack of internet access or insufficient computer skills.

Study design

This was a monocentric cross-sectional cohort study of Swiss women aged 18–85 years with the aim to assess the nutritional knowledge of healthy women and women with metabolic syndrome. The study utilized an anonymous online questionnaire to collect data from participants, ensuring the confidentiality of the participants’ responses. To report on this study we used the STROBE criteria.¹²

Outcomes

The study aimed to evaluate various outcomes related to nutrition knowledge among Swiss women.

Primary outcome:

• The primary endpoint was the number of correct answers on a questionnaire assessing knowledge about nutrition.

Secondary outcomes:

• Comparison of nutrition knowledge across the four language regions in Switzerland (German, French, Romansh, and Italian).

• Comparison of nutrition knowledge between healthy women and those diagnosed with metabolic syndrome.

• Assessment of the influence of factors such as age and education level on nutrition knowledge.

Optimal daily intake

To define the concept of “optimal daily intake,” we referred to the Swiss dietary guidelines published by the Swiss Society for Nutrition. The optimal daily intake pertains to the recommended amounts of various food groups necessary to ensure a balanced diet. These guidelines include specific recommendations for the distribution of food groups based on the nutrient needs of the general population.

In our questionnaire, participants were asked to assess their understanding of optimal daily intake by ranking four food categories according to their optimal percentage of daily food intake (correct order: (1) fruits and vegetables, (2) starchy foods, (3) proteins, and (4) sweets). Each correct answer was scored 1 point (maximum of 4 points). To comprehensively evaluate the understanding of optimal daily intake, we also requested the percentage composition of a healthy and balanced diet plate. The available food categories included (1) bread, potatoes, and pasta, (2) fruits and vegetables, and (3) meat, tofu, and eggs (correct answer: (1) 40%, (2) 40%, (3) 20%). Each correct answer was rated with 2 points (maximum of 6 points). One point was awarded if there was a ±5% variation from the correct percentage. Any other answer received 0 points.

Questionnaire

A questionnaire was created based on the hypotheses described previously. The development process began with identifying key areas of nutrition knowledge that were essential to evaluate: subjective knowledge, objective knowledge, and practical implementation. Subjective knowledge was measured through self-reported measures of perceived understanding, while objective knowledge was assessed through standardized tests that required correct identification or application of nutritional information. To measure subjective knowledge, participants were asked to rate their understanding of various nutritional concepts on a Likert scale (1 = not at all knowledgeable to 5 = very knowledgeable). Objective knowledge was assessed using a series of questions that required participants to provide correct answers regarding nutritional content and dietary recommendations. Given the absence of a single validated questionnaire that covered all these domains comprehensively, we created a new questionnaire tailored to our research needs. To ensure the relevance and comprehensiveness of the questionnaire, we focused on several critical aspects: (1) Comprehensive coverage: we included questions that spanned various dimensions of nutrition knowledge, from basic macronutrient identification to understanding the optimal composition of a balanced diet. This holistic approach ensured that all relevant topics were covered. (2) Relevance and clarity: questions were crafted to be straightforward and relevant to everyday dietary decisions. They were pretested by ten female volunteers who provided feedback on clarity and potential biases. This step ensured that the questions were understandable and non-suggestive, thereby minimizing interviewer bias. The questions were also checked for statistical evaluability. (3) Cultural and linguistic adaptation: the questionnaire was set up in German and translated into French, Italian, and Romansh by native speakers and subsequently tested by eight female volunteers from each language region in Switzerland. This process ensured that the questionnaire was culturally and linguistically appropriate across different regions.

The final questionnaire consisted of 18 questions covering four categories: (1) participants’ characteristics, (2) relevance of nutrition to the individual, (3) subjective knowledge, and (4) objective knowledge about nutrition (Supplemental File 1).

In detail, in part D participants were asked to assign 11 food items to their dominant macronutrient component (carbohydrates (C), proteins (P), fat (F)) (correct answers: vegetables: C, potatoes: C, chicken breast: P, avocado: F, chocolate: F, eggs: P, olive oil: F, tree nuts: F, milk: P, fruits: C, pasta: C). Each correct answer was rated with 1 point (maximum 11 points). Next, participants were to rank four food categories according to their optimal percentage of daily food intake (correct order: (1) fruits and vegetables, (2) starchy foods, (3) proteins, (4) sweets). Each correct answer was rated with 1 point (maximum 4 points). Finally, the percentage composition of a healthy and balanced diet plate was requested. Available food categories were (1) bread, potatoes, and pasta, (2) fruits and vegetables, and (3) meat, tofu, and eggs, respectively (correct answer: (1) 40%, (2) 40%, (3) 20%). Each correct answer was rated with 2 points (maximum 6 points). One point was given if there was a ±5% variation from the correct percentage. Any other answer was rated with 0 points.

The sources used to determine the macronutrient composition of foods were the guidelines from the Swiss Society for Nutrition, which include the Swiss food pyramid and the plate model. These models provided a framework for evaluating participants’ objective nutrition knowledge.^4,5 The questionnaire was programmed on the online platform “Findmind” (https://www.findmind.ch). The link to the questionnaire was distributed broadly by e-mail, social media, and professional, and personal networks, including a snowball sampling strategy to avoid a possible selection bias.¹³ The questionnaire was online from the beginning of June 2018 until the end of May 2019. This 1-year period was selected to ensure a sufficiently large and diverse sample size, capturing seasonal variations in dietary habits and allowing ample time for broad dissemination across all language regions of Switzerland.

Sample size calculations

The study population comprised participants from various language origins: German (52.3%), French (24.6%), Romansh (21.6%), and Italian (1.2%). Ethical approval in 2022 was supported using 95% confidence intervals (CI) with specific margins of error for assessing response behavior. With a sample size of N = 95, the 95% CI had a ±10% margin of error, facilitating robust comparisons. Reducing the margin to ±15% decreased the required sample size to N = 42 per subgroup. Although recruitment did not achieve equal distribution across language regions, statistical analyses demonstrated robust results primarily for the German-speaking group. CI within ±15% for French and Romansh validated the study’s statistical reliability despite uneven representation.

Statistical analyses

Within the following 11 months (June–April) the obtained data were statistically analyzed. Frequency distributions of all responses were determined. Mean and standard deviations were performed if convenient. For subgroup comparisons, Fisher’s test was used for categorical data, and for larger than 2 × 2 panels, Fisher–Freeman–Halton test was implemented in SPSS (IBM Corp., Armonk, NY, USA). Mann–Whitney-U test was used for metric or ordinal data for two independent groups, Kruskal–Wallis test for more than two independent groups. p-values were indexed according to the test used. Values less than 5% were considered statistically significant, without any correction due to multiple testing.

Results

Overall, 524 women participated in the survey. Among them, 447 women met the inclusion criteria and were included in the analysis (n = 447). Background characteristics (see Table 1) indicate that the majority of participants were aged 18–44 years (71.1%), with 75.5% having a BMI < 25 kg/m². The largest language group was German-speaking (52.3%), and 52.6% had a university degree. Employment status varied, with approximately one-third working part-time (29.8%) or full-time (27.1%).

Table 1.

Characteristics of 447 women taking part in a cross-sectional cohort study (online survey) in Switzerland (2018–2019).

Characteristic	Category	Number of participants (n) (%)
Total participants		447 (100.0)
Age	Reported age	329
	18–44 years	234 (71.1)
	45–65 years	73 (22.2)
	⩾65 years	22 (6.7)
BMI	Reported BMI	329
	Mean ± SD	22.9 ± 4.2 kg/m²
	Range	13.9–40.5 kg/m²
	<25 kg/m²	246 (75.5)
	⩾25 kg/m² (overweight/obese)	80 (24.5)
Language origin	German	173 (52.3)
	French	81 (24.6)
	Romansh	71 (21.6)
	Italian	4 (1.2)
Educational level	Reported educational level	327
	University degree	172 (52.6)
	Grammar school/Vocational middle school	90 (27.5)
	Lower educational level	65 (19.9)
Employment status	Part-time work	133 (29.8)
	Full-time work	121 (27.1)
	Full-time housewife	16 (3.6)
	Retired	34 (7.6)
	Trainee	140 (31.3)

BMI: body mass index; SD: standard deviation.

Table 2 presents the relevance of nutrition to individuals. A majority (91.7%, n = 408) of women prioritize paying attention to a healthy diet, citing reasons such as following a healthy lifestyle (80.4%, n = 328) and weight loss (36.8%, n = 150). About 69.8% do not follow a specific diet. Half (49.3%, n = 214) of those surveyed apply their nutritional knowledge to daily life. Main obstacles to maintaining a healthy diet include cravings for unhealthy food (44.4%, n = 220), lack of time (32%), and emotional eating (29%, n = 220).

Table 2.

Relevance of nutrition for women taking part in a cross-sectional cohort study (online survey) in Switzerland (2018–2019).

Dietary practices	(Rather) Yes (n = 408)		(Rather) No (n = 37)
Paying attention to a healthy diet	Disease-related	46 (11.3%)	No interest	11 (27.9%)
	Weight loss	150 (36.8%)	No time	15 (40.5%)
	General healthy lifestyle	328 (80.4%)	Pleasure has priority	23 (62.2%)
	Work/hobby-related	43 (10.5%)	Cost	7 (18.9%)
	Others	26 (6.4%)	Lack of information	7 (18.9%)
	Others	26 (6.4%)	Others	2 (5.4%)
Following a specific diet	Vegetarian	47 (9.9%)	332 (69.8%)
	Vegan	10 (2.1%)
	Food allergies/intolerances	34 (7.1%)
	Others	41 (8.6%)
Applying knowledge about healthy diet on a daily basis	214 (49.3%)		220 (50.7%)
Only partly applying knowledge on healthy diet	Being an emotional eater	64 (17.1%)	N/A
	Lack of interest	13 (3.5%)
	Lack of time	71 (19%)
	Lack of attention on weekends	41 (11%)
	Occasional cravings for unhealthy food	166 (44.4%)
	Others	19 (5.1%)
Never applying knowledge on healthy diet	Being an emotional eater	3 (21.4%)	N/A
	Lack of interest	1 (7.1%)
	Lack of time	3 (21.4%)
	Lack of attention on weekends	1 (7.1%)
	Occasional cravings for unhealthy food	4 (28.6%)
	Others	(14.3%)

Most respondents (79.1%, n = 340) believe their body weight reflects their diet, and a majority (79%, n = 339) feel confident in assigning food items to macronutrient groups. Additionally, 68.6% (n = 290) know the Swiss Society for Nutrition recommends colorful plates to enhance micronutrient coverage. The “nutrition pyramid” model is more widely recognized than the “plate model” (95% versus 49.4%). Sources of nutrition information primarily come from laypersons (23.5%) and the lay press (42.9%).

Participants were tested on nutrition knowledge. On average, they correctly assigned 8.7 ± 1.7 food items to their dominant macronutrient group. Only 38.8% accurately ranked four food categories by optimal daily intake percentages. When asked to compose a healthy and balanced diet plate, 5.3% achieved the maximum score (6 points), 3.5% attained at least half (3–5 points), and 91.2% were mostly incorrect (<3 points).

Educational level was divided into three categories: low (compulsory school), standard (high school/vocational secondary school), and high (university/college). 327 participants (62.4%) reported their educational level. 325 answered the question addressing the reason the “Swiss Society for Nutrition” recommended making the plate as colorful as possible. Of those, 235 (71.9%) knew the correct answer. Highly educated women (82.6%) were significantly more likely to give the correct answer compared to women with standard (63.3%) or low educational level (55.4%; p < 0.001). Regardless of educational level, the nutrition pyramid was better known than the plate model (p = 0.055). However, even if participants were not aware of a nutrition model, educational level did affect the likelihood of applying it in daily life. When being asked to allocate 11 food items to the dominant macronutrient group, intergroup comparisons revealed significant differences. Subjects with standard educational levels scored better (9.2 ± 1.5 points) compared to less educated women (8.2 ± 1.8 points; p < 0.001). However, there was no statistically significant difference when compared to highly educated women (8.9 ± 1.8 points; p = 0.607). Similarly, educational level had an impact on ranking the amount of four food categories to be consumed daily. The higher the educational level the more likely the correct ranking was chosen (high level 2.7 ± 1.3 points versus standard level 2.4 ± 1.3 points; p = 0.044; high level versus low level 1.9 ± 1.4 points; p < 0.001; standard versus low level; p = 0.035). However, education did not have an impact on estimating the recommended percentage of three food categories that make up a healthy and balanced diet (p = 0.602, data not shown).

BMI was divided into two categories: normal (BMI ⩽ 25) and overweight/obesity (BMI > 25). Three hundred and twenty-six participants (62.2%) reported their BMI. Three hundred and twenty-five answered the question addressing the reason the “Swiss Society for Nutrition” recommended making the plate as colorful as possible. Of those, 234 (72%) knew the correct answer. However, women with overweight/obesity were less likely to give the correct answer (BMI ⩽ 25 75.5% (n = 185) versus BMI > 25 61.3% (n = 49); p = 0.021). Regardless of BMI, the nutrition pyramid was better known than the plate model; (p = 0.051). However, even if participants were aware of the nutrition model, BMI did not have an impact on the likelihood of applying it in daily life. When being asked to allocate 11 food items to the dominant macronutrient group, intergroup comparisons did not reveal significant differences (p = 0.725) (data not shown). In contrast, BMI had a significant impact on ranking the amount of four food categories to be consumed daily. Women with normal BMI scored better on the ranking (BMI ⩽ 25 2.6 ± 1.4 points versus BMI > 25 2.0 ± 1.2 points; p < 0.001). When being asked to estimate the recommended percentage of three food categories that make up a healthy and balanced diet, no significant differences between BMI categories were found (p = 0.577) (data not shown). The majority of women (97.5%) agreed to apply their knowledge about healthy and balanced nutrition at least sometimes. However, reasons for not applying knowledge were not dependent on BMI (data not shown). In general, participants felt that their body weight reflected their diet. However, this was more likely to be true for normal-weight than for overweight/obese women (85.8% versus 68.8%; p < 0.001). Similarly, more overweight/obese than normal-weight women felt their BMI was too high for their eating habits (28.8% versus 3.3%; p < 0.001).

Three hundred and twenty-nine participants (62.8%) reported their language origin (German: n = 173 (52.6%), French: n = 81 (24.6%), Romansh: n = 71 (21.6%), Italian: n = 4 (1.2%)). Due to the low number of women of Italian origin, they were not further considered. Overall, 236 women (71.7%) knew why the “Swiss Society for Nutrition” recommends making the plate as colorful as possible. German-speaking women were most likely to give the correct answer (German: n = 142, 82.1% versus Romansh: n = 45, 63.4% versus French: n = 45, 55.6%; p < 0.001). Irrespective of language origin, sources of information were mainly laypersons (51.7%), or lay press (74.8%), respectively. Similarly, irrespective of language origin, the nutrition pyramid was better known than the plate model (p = 0.047). However, if participants were aware of either nutrition model, language origin had a significant impact on the likelihood of applying it at least most of the times (e.g., food pyramid: German n = 114, 65.9% versus French n = 44, 54.3% versus Romansh n = 35, 49.3%; p = 0.04). When being asked to allocate 11 food items to the dominant macronutrient group, intergroup comparisons revealed significant differences with German-speaking women scoring best (German 9.3 ± 1.3 points versus Romansh 8.6 ± 1.8 points versus French: 8.1 ± 1.9 points; p < 0.001). Language origin also had a significant impact on ranking the amount of four food categories to be consumed daily (p = 0.019) but not on estimating the recommended percentage of three food categories that make up a healthy and balanced diet (p = 0.232) (data not shown).

Personal interest in nutrition was binary-coded as “yes” or “no”. 91.7% (408 out of 445) agreed to paying attention to a healthy diet. Of 423 respondents addressing why the Swiss Society for Nutrition recommends colorful plates, 68.5% (290) answered correctly. There was a nonsignificant trend toward correct answers among those attentive to diet (p = 0.080). Regardless of interest in nutrition, the nutrition pyramid model was better known than the plate model (p = 0.019). Those attentive to diet were significantly more likely to apply either model (p < 0.001). However, interest in nutrition did not significantly affect daily food category ranking (p = 0.784) or estimating balanced diet percentages (p = 0.661, data not shown).

Overall, 429 women responded. Women confident in their nutritional knowledge were significantly more likely to correctly address the Swiss Society for Nutrition recommendations compared to those less confident (p < 0.001). The association between knowledge of nutrition models and self-perceived ability to classify food items by macronutrients was explored by 417 respondents (Tables 3 and 4). As expected, well-educated women frequently applied the nutrition pyramid model. Interestingly, also most women who believed to have little or no knowledge about food composition reported to apply the “nutrition pyramid” model at least sometimes.

Table 3.

Knowledge about the “nutrition pyramid” model in the context of self-perceived ability to correctly assign food items to the dominant macronutrient groups (n = 447 women) (2018–2019). Results from a cross-sectional cohort study (online survey) in Swiss women aged 18–85 years.

Cross-tabulation of Q10 and Q7	“Nutrition pyramid” . . . (Q10)	. . . is known and applied daily (n (%))	. . . has been heard of and is mostly applied (n (%))	. . . has been heard of and is sometimes applied (n (%))	. . . has never been heard of or has not been understood (n (%))	p-value
Perceived ability to correctly assign food items to the dominant macronutrient groups (carbohydrates, proteins, fat) (Q7)
To be always able (n (%))	110	39 (35.5)	51 (46.4)	18 (16.4)	2 (1.8)	<0.001
To be mostly able (n (%))	222	25 (11.3)	104 (46.8)	82 (36.9)	11 (5.0)
To be somewhat able (n (%))	63	3 (4.8)	17 (27.0)	38 (60.3)	5 (7.9)
Not to be able (n (%))	22	3 (13.6)	4 (18.2)	12 (54.5)	3 (13.6)
	Total (n = 417)	70	176	150	21

Table 4.

Knowledge about the “plate model” in the context of self-perceived ability to correctly assign food items to the dominant macronutrient groups (n = 447 women) (2018–2019). Results from a cross-sectional cohort study (online survey) in Swiss women aged 18–85 years.

Cross-tabulation of Q10 and Q7	“Plate model” . . . (Q10)	. . . is known and applied daily (n (%))	. . . has been heard of and is mostly applied (n (%))	. . . has been heard of and is sometimes applied (n (%))	. . . has never been heard of or has not been understood (n (%))	p-value
Perceived ability to correctly assign food items to the dominant macronutrient groups (carbohydrates, proteins, fat) (Q7)
To be always able (n (%))	110	18 (16.4)	28 (25.5)	30 (27.3)	34 (30.9)	<0.001
To be mostly able (n (%))	222	8 (3.6)	44 (19.8)	53 (23.9)	117 (52.7)
To be somewhat able (n (%))	63	0	7 (11.1)	13 (30.6)	43 (68.3)
Not to be able (n (%))	22	1 (4.5)	1 (4.5)	3 (13.6)	17 (77.3)
	Total (n = 417)	27	80	99	211

Discussion

Our cross-sectional online survey of generally well-educated, normal-weight, young to middle-aged, working women from the four language regions in Switzerland found that (1) the topic of nutrition was highly important, (2) information on nutrition was mainly derived from nonexperts, and (3) most women were convinced to be well-educated about nutrition. However, (4) this self-concept was only partly true as indeed, (5) subjectively body weight reflected diet at most times, (6) the term “nutrition pyramid” was well known, and (7) assignment of food items to the correct dominant macronutrient component was mostly correct. In contrast, (8) ranking of food categories according to their optimal percentage of daily food intake, and (9) percentage composition of a healthy diet out of four food categories were poor.

Understanding the intersection of sociocultural factors with education and BMI could provide deeper insights into the barriers to implementing nutritional knowledge. For instance, sociocultural influences such as family dietary traditions, peer behaviors, and cultural attitudes toward body image may interact with an individual’s educational background and BMI. These interactions could shape food choices and perceptions of nutritional knowledge.

Obviously, results may have been influenced by several factors such as education, BMI, language origin, and personal interest in nutrition. In subsequent subgroup analyses we found that (1) the “nutrition pyramid” was better known than the “plate model” regardless of education, BMI, language origin, and personal interest in nutrition, (2) higher educational level was associated with more objectifiable knowledge on nutrition, and (3) compared to overweight/obese women, normal-weight women scored better on specific questions such as colorful plate and ranking of the four food categories but did not show overall superior knowledge or application in other areas. There were no significant differences in the likelihood of applying nutrition models in daily life or the reasons for not applying the knowledge.^4,5

Interestingly, (4) there was a BMI-dependent difference in self-perceived eating habits and BMI with overweight/obese women being significantly more often convinced that their BMI was too high for their eating habits. Overall, (5) German-speaking women and those with personal interest in nutrition were slightly more knowledgeable about nutrition and were more likely to apply their knowledge on a daily basis. (6) The reasons for not applying the knowledge did not depend solely on BMI but also on other bio-psycho-social factors. These factors include physical activity levels, stress, comorbidities such as depression, family environment, and cultural background, as covered by specific questions in our questionnaire. (7) A general interest in nutrition was associated with more knowledge about healthy eating but, (8) contrary to our expectations, women were able to assess very well how great their knowledge about nutrition was.

Indeed, regardless of BMI, a healthy diet is a relevant topic for most Swiss people.¹⁴ However, other factors than healthy food are relevant for food choice.¹⁵ In a European study food costs were the main reason for food choice in most countries (Spain, Greece, Ireland, Portugal, the Netherlands) followed by sensory attraction (smell, appearance, taste) (Norway, Germany, Great Britain) while only in Poland the natural content of food was the most important factor.¹⁶ Overall, cost, sensory attraction, and natural food content were considered the most important factors. The factor health with the following sub-categories (high vitamin and mineral content, rich in protein and fibers, keeps me healthy, etc.) was ranked fourth, followed by factors like convenience (easy preparation, good availability, etc.), mood (helps me to relax, deal with stress, etc.) and weight control. Ethical reasons were the least important factor in food.¹⁶ Thus, even if enough knowledge about healthy and balanced nutrition was available, it would not necessarily change food choices.

The first national nutrition survey among approximately 2000 adults in Switzerland (German, French, and Italian language region; mean BMI 24.1 in women and 25.9 in men) reported that 55% of women and 51% of men would like to lose weight. About 34% of women reported habitually follow a special diet with the most popular diet being vegetarian diet, followed by caloric and fat restriction.¹¹ Similar to our results, the national nutrition survey found that German-speaking people were more likely to follow a special diet compared to French and Italian-speaking participants. Also, the term “nutrition pyramid” was well known with our results showing a slightly higher prevalence (95.0%) than what was found in the national nutrition survey (86.4% of women).^4,11 This difference might be due to chance, or may also reflect an increasing awareness level within the time period from 2014/2015 (national nutrition survey) to 2018/2019 (our survey). The latter hypothesis is supported by the finding that in contrast to the national nutrition survey, language origin did not have an impact (anymore) on knowing the “nutrition pyramid” in our survey.

Without doubt, education has an impact on knowledge about nutrition (our study and Pandit-Agrawal et al.,¹⁷ Parmenter et al.,¹⁸ De Vriendt et al.¹⁹). However, knowing something theoretically does not automatically mean transferring the knowledge into practice. While some studies found a positive association between education and applying a healthy diet, others, like us, did not. In our survey women that were aware of a certain nutrition model were not more likely to apply it on a daily basis if they were better educated.^20,21 In another cross-sectional study lower educational level was associated with consuming more sugary and fatty food items supporting the first study.^20,21 However, when taking the kind of energy expenditure into account, the study found that people with higher education more likely spent energy working out (sports, leisure time) while people with lower education were more likely to have physically demanding jobs (working time).²⁰ Thus, when assessing the impact of education on eating behavior other bio-psycho-mental-social factors like pleasure/dislike in physical activities, comorbidities (e.g., depression), job and family environment/spare time as well as cultural background need to be considered. In respect to cultural background, Switzerland with its four language regions offers a unique opportunity to study different sociocultural influences from Northern European (Germany) and Southern European (France, Italy) heritage (ancient residents, not immigrants!). For example, significant differences in attitudes toward money,²² work,²³ music style,²⁴ and medical issues (e.g., organ donation²⁵ and breast cancer prevention²⁶) have been reported.

One important finding of your study was that information on nutrition was mainly derived from nonexperts supporting a previous report. Considering the massive amounts of “recommendations” and commercials in diet books, magazines, TV shows, podcasts, etc., it is not surprising that there are so many misleading diet concepts around which may either “brainwash” the audience (possible side effect: harmful unbalanced malnutrition), or frustrate people (possible side effect: general nonadherence, yo-yo effect).²⁷

Therefore, there is a critical need to engage both the general public and expert stakeholders (e.g., physicians, nutritionists, pharmacists, health science representatives, occupational scientists, food industry, policymakers, and information technologists) in developing a robust national or international public health nutrition strategy aimed at enhancing nutritional literacy and improving supportive environmental conditions. Initiatives such as the Swiss Nutrition Strategy 2017–2024 represent initial steps toward facilitating healthier lifestyle choices and contributing to the prevention of NCDs.²⁸

The topic of nutrition is highly important for many women. However, the quite common self-concept of being well-educated about nutrition is only partly true. Women with a higher educational level, lower BMI, and more interest in nutrition, as well as women from the German-speaking part of Switzerland, show a better knowledge about healthy nutrition. Nevertheless, not only knowledge plays a role in implementing a healthy diet, but also other psychological and mental factors (e.g., emotions and stress). Thus, provision of easy-to-implement, high-quality, and easily accessible expert information on nutrition with a focus on effortless and joyful self-empowerment, and avoiding prohibitions and threats, is necessary.

Limitations

We acknowledge several limitations in this study. First, the use of an online questionnaire introduces the potential for bias, as participants may have sought external help or consulted resources during the survey, which could have influenced the accuracy of responses, particularly regarding the measurement of objective knowledge. To mitigate this, we kept the questionnaire concise and limited the response time, although we cannot entirely rule out the possibility of external influence. Future studies could use in-person assessments or controlled environments to better account for this potential bias.

Second, the recruitment method primarily reached a homogeneous group of young to midlife women, which limits the generalizability of our findings. This homogeneity raises concerns about whether our results can be extrapolated to the broader population of Swiss women, particularly those from different age groups, educational backgrounds, or with higher BMIs. As author AV’s native language was Romansh, our cohort’s language distribution (German 52.3%, French 24.6%, Romansh 21.6%, Italian 1.2%) differed slightly from the national language distribution in Switzerland (German 62.1%, French 22.8%, Italian 8.0%, Romansh 0.5%).²⁹ Additionally, the sample did not account for individuals from other demographic groups, such as men or older adults, limiting the representativeness of our results.

Moreover, factors beyond knowledge, such as physical activity, hormonal influences, co-morbidities, stress, and genetic predispositions, may also influence food choices, yet our study design did not allow for control of these potential confounding variables. We recommend that future research includes a broader and more diverse population and considers these additional factors, to provide a more comprehensive understanding of the implementation of nutritional knowledge in daily life.

Lastly, the cross-sectional nature of our study does not allow us to infer causality between knowledge and behavior. Longitudinal studies or randomized controlled trials would be better suited to examine whether improved nutritional knowledge directly leads to healthier dietary practices over time.

Conclusion

This cross-sectional study provides valuable and recent insights into the nutritional knowledge and self-perception of Swiss women aged 18–85 years. Our findings indicate that nutrition is a highly important topic for many women, with most of their information derived from nonexperts. Many women believe they are well-educated about nutrition; however, this self-concept is only partially accurate, as there are gaps in knowledge, particularly in ranking food categories by optimal daily intake and understanding the percentage composition of a healthy diet.

Our study also revealed that nutritional knowledge is influenced by various factors, including education level, BMI, language origin, and personal interest in nutrition. Women with higher education levels, lower BMI, greater interest in nutrition, and those from the German-speaking region of Switzerland seemed to have better knowledge about healthy nutrition. However, the ability to translate theoretical knowledge into daily practice is not solely dependent on knowledge but also on other psychological and social factors.

Despite some limitations, such as the homogeneity of the sample and the potential for external assistance in completing the questionnaire, our study offers more recent insights compared to previous Swiss epidemiological studies from 2014 to 2015. This comparison highlights possible changes in the population’s awareness and knowledge over time.

Moving forward, it is essential to provide high-quality, accessible expert information on nutrition that emphasizes easy and enjoyable self-empowerment, avoiding prohibitions and threats. Public health strategies should prioritize the integration of nutritional education into school curricula and workplace wellness programs to reach diverse populations. Additionally, targeted campaigns, particularly in the French- and Italian-speaking regions, should address identified gaps in knowledge and promote simple, actionable steps toward healthier dietary habits.

Furthermore, healthcare providers and public health organizations should collaborate to create community-based initiatives that focus on increasing awareness of portion sizes, food group composition, and practical meal planning. These programs should be tailored to different educational levels and cultural backgrounds, ensuring inclusivity and relevance. Leveraging digital platforms to deliver accurate and personalized nutritional advice may also prove effective, especially among younger populations.

Additionally, considering the multifaceted nature of food choice, further research should control for various bio-psycho-social factors to better understand and promote healthy eating behaviors.

Overall, our findings underscore the need for a comprehensive public health nutrition strategy that involves collaboration among laypeople and expert stakeholders to enhance nutritional competence and improve the conditions for a healthy lifestyle in Swiss women.

Supplemental Material

sj-docx-1-whe-10.1177_17455057241302451 – Supplemental material for Women’s self-concept of and real knowledge about nutrition: A cross-sectional study

Supplemental material, sj-docx-1-whe-10.1177_17455057241302451 for Women’s self-concept of and real knowledge about nutrition: A cross-sectional study by Elena Pavicic, Annaletta Vincenz, Norman Bitterlich, Michael von Wolff and Petra Stute in Women’s Health

Supplemental Material

sj-docx-2-whe-10.1177_17455057241302451 – Supplemental material for Women’s self-concept of and real knowledge about nutrition: A cross-sectional study

Supplemental material, sj-docx-2-whe-10.1177_17455057241302451 for Women’s self-concept of and real knowledge about nutrition: A cross-sectional study by Elena Pavicic, Annaletta Vincenz, Norman Bitterlich, Michael von Wolff and Petra Stute in Women’s Health

Footnotes

Acknowledgements

The authors would like to thank all participants in the study.

Declarations

Authors’ note

Elena Pavicic is also now affiliated to Department of Obstetrics and Gynecology, University Clinic Inselspital, Bern, Switzerland.

ORCID iDs

Elena Pavicic

Petra Stute

Supplemental material

Supplemental material for this article is available online.

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