Culinary nutrition course equips future physicians to educate patients on healthy diet

Poor-quality diet is associated with one in ve deaths globally. In the United States, it is the leading cause of death, representing a bigger risk factor than even smoking. For many, education on a healthy diet comes from their physician. However, as few as 25% of medical schools currently offer a dedicated nutrition course. We hypothesized that an active learning, culinary nutrition experience for medical students would improve the quality of their diets and better equip them to counsel future patients on food and nutrition.

Globally, an unhealthy diet was responsible for 11 million deaths in 2017 1 . In the United States, poorquality diet is the leading cause of death 2 , representing a bigger risk factor for morbidity and mortality than obesity, hypertension, hypercholesterolemia, physical inactivity, and even smoking 3 . While positive dietary changes represent an obvious solution to decreasing morbidity and mortality, many patients are still unsure of what changes to make and/or how to enact them. As the quality of an individual's diet is directly correlated with their nutritional knowledge 4-10 , a lack of this knowledge, therefore, represents a major obstacle for many patients looking to adopt a healthy diet 11-13 . Physicians are both trusted and in uential sources of nutritional information for patients seeking to improve their lifestyles. Nearly 80% of patients who seek dietary information from their doctors make a subsequent change in their eating habits 14 . For this reason, a crucial element of the World Health Organisation's United Nations Decade of Action on Nutrition 2016-2025 involves doctors supporting and advocating for evidence-based nutritional practices 15 . Doctors do recognise this important role they have as an educational resource, with as many as 95% of surveyed physicians reporting that they believe it's their personal responsibility to provide nutrition counseling to their patients 16 . But this belief has yet to adequately translate into clinical practice 17 , with nutrition education being provided in as few as 12% of o ce visits 18 .
A likely cause of this discrepancy is physicians' perceived lack of preparedness to effectively counsel patients on diet. Fewer than one in six physicians feel highly con dent in their ability to discuss nutrition with patients 19,20 . Medical students and doctors who most routinely provide counseling are those who practice a healthy diet themselves [21][22][23][24][25] , suggesting that doctors' own knowledge of nutrition may play a key role in patient education.
Physicians, however, report that their formal training received in nutrition and diet counseling, particularly in medical school, is inadequate [26][27][28][29][30] . In fact, only 25% of medical schools provide a dedicated nutrition course, with this coursework frequently being done via online modules 31 . On average, medical schools in the United States provide only 19 hours of nutrition education -six fewer hours than the minimum 25 recommended by the National Academy of Medicine. In all, 71% of medical schools -serving 75% of US medical students -fail to provide their students with the minimum recommended nutrition education during their four years of training 32 . Outside of the United States, education for medical students has similarly and repeatedly been shown to be insu cient in enabling future physicians to con dently provide nutrition counseling for their patients. 30 The purpose of this study was to evaluate the e cacy of a hands-on culinary nutrition curriculum in in uencing rst-year medical students' personal dietary habits and perceived preparedness to counsel patients on a healthy diet. Educational interventions aimed at addressing doctors' nutritional knowledge gaps are becoming increasingly common in the medical education and healthcare landscapes. The most successful nutrition education interventions, recent literature has found, are practical and emphasize skill development instead of mere knowledge acquisition 33,34 . This nding is congruent with recent pedagogical research that has demonstrated the superiority of active learning in engagement and content mastery compared to lecturing alone, particularly in the science, technology, engineering, and mathematics (STEM) elds [35][36][37] . For this reason, we engaged with the burgeoning trend of active learning instruction in undergraduate medical education 38 to design this hands-on curriculum. We hypothesized that an active learning intervention would improve the quality of participants' diets and better equip them to counsel their future patients on food and nutrition.

Study Design and Sample
The investigation was a single-center, prospective, interventional, uncontrolled, non-randomised study. All rst-year medical students at the Wayne State University School of Medicine (WSUSOM) in Detroit, Michigan who completed the required Clinical Nutrition course were eligible to participate. All interested students participated in and completed the intervention. The potential bene ts of expanding the assessment of this intervention with a controlled trial are discussed further in the Discussion. The study was approved by the Wayne State University Institutional Review Board (IRB) under exempt review. All participants were older than 18 years of age and able to provide informed consent, although the need for written informed consent was waived per the IRB.

Intervention
Participants completed a four-session, eight-hour intervention called "Culinary Nutrition: A Practical

Measures and Procedures
Participants completed survey questionnaires at three timepoints: immediately pre-intervention (time 1), immediately post-intervention (time 2), and two months post-intervention (time 3). The surveys were anonymous and completed online using SurveyMonkey.com (SurveyMonkey, San Mateo, California). The questionnaires were informed by those in the literature and developed speci cally to assess this curriculum. They asked participants to quantitatively rate their behaviors and attitudes regarding health, wellness, and anticipated effectiveness in counseling patients about a healthy diet on a Likert scale from 0 ("do not agree at all") to 10 ("completely agree") (see supplementary data for questionnaires). Each questionnaire also included an objective test of participants' culinary knowledge. Anonymous codenames generated by participants were used to link individuals' responses across the three survey waves.
The primary outcomes were within-subject changes in medical students' attitudes about counseling patients on the tenets of a healthy lifestyle. Speci cally, participants were asked to rate how prepared, motivated, and excited they were to counsel patients on practicing a healthy lifestyle. Secondary outcomes included changes in subjects' culinary knowledge over time and whether they reported positive changes in personal dietary habits between the pre-and post-intervention timepoints, such as eating more homemade and less pre-prepared food.

Data Analysis
All analyses were conducted in Stata 14.2 (StataCorp, College Station, Texas). After calculating group means for each outcome variable at each of the three timepoints, we used ordinary least-squares (OLS) xed-effect (FE) models to estimate the average within-person change in each outcome between timepoints. OLS was used because all outcomes were continuous. With the exception of percent of meals homemade, all were measured from 0 to 10. For all but four models, there were no missing data for any individual-time observation. In those four models, one timepoint had only nine valid responses; for these, the missing observation was deleted listwise, and the models included 29 rather than 30 observations. The main explanatory variable was time, which was included in the models as a three-category factor variable, with baseline (time 1) as the reference group. The models included this time variable and individual xed effects. Individual xed effects allowed us to account for the differing starting positions of each participant at baseline. Moreover, FE models estimate standard errors based on within-person change over time, which nets out any stable differences across individuals -such as demographics, stable dietary restrictions, etc. -from our analyses. As such, our estimates for the impact of the intervention can be interpreted as causal with the large assumption that nothing else systematically changed at the same times to also affect the outcome variables. For all analyses, statistical signi cance is de ned as P ≤ .05.

Results
Ten rst-year medical students enrolled in the practical course, and there was a 100% retention rate; every participant attended each of the four sessions. There was a 98.8% survey item completion rate for the associated three waves of questionnaires. At baseline, the participants reported being both highly motivated (mean = 8.2 points) and excited (mean = 8.2 points) to counsel patients on practicing a healthy lifestyle. In contrast, participants at baseline did not rate themselves as feeling highly prepared (mean = 4.8 points) to do so (Table 1). On average, respondents' self-reported preparedness was signi cantly higher immediately post-intervention (coe cient = 2.8 points; 95% con dence interval [CI]: 1.6 to 4.0 points; P < .001) and two months postintervention (2.2 [1.0, 3.4]; P = .002) compared to baseline. There was no signi cant decline in respondents' preparedness between the immediately post-and two months post-intervention surveys (-0.6 [-1.8, 0.6]; P = .32) ( Table 2). Neither self-reported motivation nor self-reported excitement changed signi cantly from baseline at either of the follow-up timepoints ( Table 2).  Participants also rated the effectiveness of the training that they had received in preparing them to counsel patients on a healthy lifestyle. Speci cally, the questionnaires asked if they felt they had the medical, nutritional, and culinary knowledge necessary to counsel patients on a healthy lifestyle. At baseline, participants on average felt that they had the medical knowledge (mean = 6.0 points) and nutritional knowledge (mean = 5.9 points) necessary. They did not feel that they had the necessary culinary knowledge, however (mean = 4.5 points) (Fig. 2). Immediately post-intervention, there were statistically signi cant increases in participants' con dence in their medical (

Additional Findings
Participants reported at baseline that they believed that culinary knowledge could be used to positively impact both their health (mean = 8.8 points) and wellness (mean = 8.8 points) ( Table 1) Despite their belief in the importance of culinary knowledge and skills for health and wellness, participants did not initially believe that they had the necessary culinary knowledge (mean = 4.7 points) or skills (mean = 4.5 points) to practice a healthy lifestyle themselves. Post-intervention, the participants felt signi cantly better equipped (Fig. 3). Mean rating of belief in their culinary knowledge increased to 7. In addition to self-reporting their perceived level of culinary knowledge, participants' culinary knowledge was also measured via a 10-point objective assessment. Pre-intervention, participants had a mean score of 5.3 points out of a possible 10.0 points. Immediately post-intervention, the mean score had increased signi cantly to 8.8 points (3.6 [2.4, 4.9]; P < .001). By two months post-intervention, the mean score had decreased to 6.9 points (Fig. 4). Participants' objective culinary knowledge scores at two months postintervention were signi cantly decreased compared to immediately post-intervention (-2.0 [-3.2, -0.8]; P = .003) but were still statistically higher than their baseline scores (1.6 [0.4, 2.9]; P = .01).
Lastly, surveys also included questions regarding participants' eating habits and personal attitudes about living a healthy lifestyle. Participants were highly motivated at baseline to practice a healthy lifestyle (mean = 7.8 points) (  19,20 . A major reason for this is that dedicated nutrition training in medical school is both limited in scope and impractical; it is often virtual lecture-based and thus detached from the real-life skills necessary to prepare nutritious meals and counsel patients. Moreover, even when physicians are educated in nutrition, as they are at the medical school serving as the site of this study, there still frequently exists a knowledge gap in how to apply that knowledge to achieve a healthy diet. To ll these gaps, we tested an interactive, practical, skills-based intervention for medical students designed to improve their knowledge of and con dence with nutrition basics and culinary skills. The ultimate goal of this intervention was to better prepare future physicians to effectively counsel their patients on food and nutrition.
Similar to the ndings of Hicks and Murano 19 and Vetter et al. 20 , we found that our medical student participants did not feel highly prepared to effectively counsel patients on how to practice a healthy lifestyle pre-intervention: no respondents rated themselves a 7 out of 10 or higher when asked to selfassess their preparation in the baseline survey. However, after the intervention, participants' self-rated preparedness to counsel patients on a healthy lifestyle was signi cantly higher. Ninety percent of respondents rated themselves to be a 7 out of 10 or higher on this item in both the immediately postintervention and two months post-intervention surveys, which also reveals the durability of the active learning course's effects. There were simultaneous increases in participants' perceptions that they had the medical, nutritional, and culinary knowledge necessary to effectively counsel patients.
Participants' perception of increased knowledge was mirrored in tests of their objective culinary knowledge, which also increased post-intervention compared to pre-intervention. Despite a decline in objective culinary knowledge at two months post-intervention compared to immediately post-intervention, participants' objective culinary knowledge two months post-intervention was still higher overall than before they took the course.
In summary, we show that an interactive culinary nutrition course for medical students can improve their culinary knowledge and their con dence in counseling patients about food and nutrition. We nd evidence that these improvements can be retained over time, even after a relatively small-scale (8-hour), short-term intervention such as this. We attribute the success of this intervention in large part to its practical and interactive nature, which the literature also nds to be the most effective method of nutrition education 33,34 .
Our study has a number of limitations. Primarily, we ran a small, non-randomised, uncontrolled intervention. Although statistical analyses were done speci cally to assess within-person change, replication of this intervention with a larger sample size would afford greater statistical power and further con rmation of this study's results. A controlled study with randomised assignment to the intervention should also be established to remove the possibility of self-selection bias. Recall bias and social desirability bias may also have impacted the results. A larger bank of culinary knowledge test questions should be developed and randomised to participants at each of the timepoints to minimise the potential that recall bias contributes to the score increase observed between the objective pre-and postintervention assessments. Finally, although the surveys were fully anonymous, participant self-reporting may over-report learning and/or under-report remaining doubts if participants felt the desire to "pay back" the instructor and principal investigator, N.I. Wood, with such reviews. Of note, this limitation is somewhat mitigated by the objective assessment of culinary knowledge included at every survey timepoint.

Implications for Future Research and Practice
Practical culinary nutrition interventions can build on the curriculum used here in a number of ways.
Delivering this curriculum to an entire medical school class will be challenging. However, amid the growing landscape of remote learning and video conference calls brought on by the coronavirus disease 2019 (COVID-19) pandemic, we are con dent that online or hybrid versions of this course could be piloted as an e cient means of scaling up the curriculum. What is most important is to see the impact of the curriculum and hands-on experience on the counseling behavior of medical students. Therefore, future research should assess the impact of this intervention on the frequency and/or quality of nutrition counseling provided. Such efforts should be paired with ongoing research to further re ne the pedagogical approaches that best prepare physicians to help their patients follow a healthy diet. Further research will also be necessary to determine what effect, if any, a practical culinary nutrition course for physician trainees has on the overall healthiness of participants' diets.

Conclusions
We conclude that participating in a hands-on culinary nutrition curriculum is an effective method for increasing medical students' readiness to counsel patients on a healthy diet. We hypothesize that this improvement is due to the intervention's active learning, which reinforces content taught in both the optional culinary nutrition curriculum as well as the compulsory clinical nutrition course. Providing nutrition education programs to medical students with hands-on learning opportunities to put into practice the clinical nutritional knowledge learned in the classroom has the potential to bridge the gap between knowledge and practical patient care. The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.

COMPETING INTERESTS:
The authors declare that they have no competing interests. Participants' Self-Reported Mastery of Necessary Medical, Nutritional, and Culinary Knowledge to Counsel Patients Legend: Medical students' self-ratings of whether they have the medical, nutritional, and culinary knowledge to effectively counsel patients on a healthy lifestyle increased signi cantly from preintervention (time 1) to immediately post-intervention (time 2). Gains were sustained two months postintervention (time 3). 83% con dence intervals obtained from linear regression models with individual xed effects are shown.

Figure 3
Participants' Self-Reported Mastery of Necessary Culinary Knowledge and Skills to Practice a Healthy Lifestyle Legend: Medical students' self-ratings of whether they have the culinary knowledge and skills to practice a healthy lifestyle increased signi cantly from pre-intervention (time 1) to immediately postintervention (time 2). Gains were sustained two months post-intervention (time 3). 83% con dence intervals obtained from linear regression models with individual xed effects are shown.

Figure 4
Participants' Scores on an Assessment of Objective Culinary Knowledge at Pre-and Post-Intervention Timepoints Legend: Medical students' objective culinary knowledge increased signi cantly from preintervention (time 1) to immediately post-intervention (time 2). Objective culinary knowledge remained signi cantly higher than baseline at two months post-intervention (time 3). 83% con dence intervals obtained from linear regression models with individual xed effects are shown.

Supplementary Files
This is a list of supplementary les associated with this preprint. Click to download. AdditionalFile1.docx