Studying the Effects of Stress Management on the Intention of People Suffering from Irritable Bowel Syndrome to Initiate the Low FODMAP Diet
Eva Dambrink 10372482
Master’s Thesis
Graduate School of Communication Master’s Program Communication Science
Supervisor: dr. Claartje ter Hoeven June 28, 2019
Abstract
Irritable Bowel Syndrome (IBS) is a common gastrointestinal disorder, which is often treated with the low FODMAP diet. This diet has many restrictions and is therefore hard to initiate. Therefore, two research objectives were central to this study. Firstly, it was studied whether a stress management exercise, through enhancing self-efficacy, could increase the intention of IBS-diagnosed people to initiate the low FODMAP diet. Secondly, it was studied whether the effects of the stress management exercise differed for two different modalities, namely text and animation, and text alone. It was expected that stress management would increase intention to start the low FODMAP diet, and that self-efficacy would mediate this effect. Furthermore, it was expected that the stress management exercise that was instructed in text and animation would result in a stronger effect of stress management on self-efficacy and on intention. A 2x2 between-subjects design was carried out in which participants were assigned to one of four conditions, of which two stress management and two control
conditions. Participants completed an online questionnaire, measuring for self-efficacy and intention to start the low FODMAP diet, after the experiment was done. Results showed no significant effects for the proposed hypotheses.
Keywords: self-efficacy, intention, modality, irritable bowel syndrome, low FODMAP diet
Studying the Effects of Stress Management on the Intention of People Suffering from Irritable Bowel Syndrome to Initiate the Low FODMAP Diet
Irritable Bowel Syndrome (IBS) is a functional gastrointestinal disorder that is characterized by symptoms of chronical abdominal pain, abnormal bowel habits, and lack of recognizable etiology (Alammar & Stein, 2019). Furthermore, recent studies show evidence for the association between IBS and psychological distress, such as increased levels of anxiety, stress, and depression (Balikji, Mackus, Kraneveld, Garssen, & Verster, 2019;
Barbalho, Goulart, Araújo, Guiguer, & Bechara, 2019). IBS affects approximately 10-15% of the Western population (Molina-Infantea, Serrab, Fernandez-Banares, & Mearin, 2015), and can, therefore, be considered a major health issue. As scientists have not been able to find a lasting solution for the disorder yet, people diagnosed with IBS are often recommended to start a low FODMAP diet, which refers to a diet restricting rapidly fermentable, short-chain carbohydrates. The acronym FODMAP stands for specific groups of such carbohydrates, namely Fermentable Oligo-, Di-, Mono-saccharides And Polyols, which include for example fructans, lactose and fructose (Manning & Biesiekierski, 2018). These FODMAP’s have in common that they are poorly or not at all absorbed by the small intestine. As a result, these carbohydrates end up in the colon where they are being fermented very quickly by large amounts of bacteria. Gas formation as a result of this process leads to symptoms such as flatulence or a bloated feeling. While the low FODMAP diet has proven to be effective for symptom reduction (Gibson, 2017), several limitations of the diet, such as a high level of restriction, potential nutritional deficiencies, and the need for monitoring by an expert, make it hard to initiate the low FODMAP diet (Molina-Infantea, Serrab, Fernandez-Banares, & Mearin, 2015). Given the complexity of the diet, a health intervention is suggested to increase the intention of people diagnosed with IBS to initiate the low FODMAP diet.
Different studies have provided evidence that self-efficacy is a key determinant for behavior (Bandura, 1977; Fishbein & Cappella, 2006), and for dietary behavior in specific (Prestwich et al., 2014). Self-efficacy refers to “beliefs in one’s capabilities to organize and execute the courses of action required to produce given levels of attainments” (Bandura, 1998, p. 624). In the context of the low FODMAP diet, self-efficacy is about the confidence people have that they are able to follow the diet. Furthermore, Prestwich et al. found strong evidence that stress management is an effective strategy for increasing dietary self-efficacy. As the previously mentioned limitations of the low FODMAP diet are likely to be perceived as barriers, which could prevent people from starting the diet, dietary self-efficacy is an important determinant of intention to initiate the low FODMAP diet. Since stress
management has proven to be an effective tool for self-efficacy enhancement (Prestwich et al., 2014), the effects of stress management on self-efficacy will be studied in the context of IBS and the low FODMAP diet. More concretely, it will be tested whether IBS sufferers’ self-efficacy towards the low FODMAP diet increases after doing a stress management exercise, and whether this also influences their intention to initiate the low FODMAP
diet. Furthermore, the stress management exercise will be tested in two different modalities, namely in text and in a combination of text and animation, as this combination has proven to be more effective than words alone (Mayer, 2002).
This study aims to contribute to the existing literature in two ways. Firstly, the study aims to find out whether self-efficacy is an important determinant of dietary behavior in the IBS context, as the goal of this diet is symptom improvement, which is different from diets focusing on reducing weight. Secondly, the study aims to find out whether modality, in either text and animation or text alone, has an effect on the execution of a stress management
exercise, while existing literature on modality focuses on effectiveness of the processing and recall of information (Mayer, 2002; Brünken & Leutner, 2001; Tindall-Ford, Chandler, &
Sweller, 1997). Based on the previous discussion, this study aims to answer the following research questions:
Research question 1: Can stress management, through enhancing self-efficacy, influence the intention of people suffering from IBS to initiate the low
FODMAP diet?
Research question 2: How does the impact of a stress management exercise differ for text and animated instructions, compared to text-only instructions?
Theoretical Framework Influencing Intention to Start a Low FODMAP Diet
Multiple studies confirmed the effectiveness of the low FODMAP diet, with the result of symptom reduction in people with IBS (Nanayakkara, Skidmore, O’Brien, Wilkinson, & Gearry, 2016; Gibson, 2017). However, the difficulties and limitations of the strict diet are likely to prevent people from initiating the diet. In order to influence one’s behavior, the right determinant for behavior should be targeted. Fishbein (2000) studied a large number of theories, among which are the health belief model, social cognitive theory, and the theory of reasoned action, and based on his findings he suggested that only a few variables should be considered in predicting any given behavior. Fishbein, therefore, proposed an integrative model that includes a combination of theories about behavior. According to the model, intention is a strong predictor for behavior, which is why the current study will focus on intention to start the low FODMAP diet, since studying behavior would preferably take multiple measures over a period of time. Furthermore, Fishbein argues that direct
determinants of intention include attitudes, norms, and self-efficacy. Attitudes are described as a function of underlying beliefs about the outcomes of the behavior. A person might, for example, believe that the low FODMAP diet reduces his or her IBS symptoms, and therefore
hold a positive attitude towards the diet. Secondly, norms refer to the normative proscriptions and behaviors of other individuals that a person identifies with. For example, when
celebrating someone’s birthday, a person with IBS might believe that others will not approve of him or her when deciding not to have cake as it might contain high FODMAP ingredients. Finally, self-efficacy refers to underlying beliefs about specific barriers to a behavior. Since this study builds on the idea that different barriers prevent people from initiating the low FODMAP diet, self-efficacy will be discussed in more detail later in this chapter. Behavior Change Techniques and Stress Management
When a specific determinant of behavior has been selected as the focus of an intervention, it is key to identify the right theoretical methods and practical application thereof. A large number of behavior change techniques (BCTs) has been cataloged in extensive lists, serving as a useful framework for behavior change interventions. Most BCTs directly target certain behaviors. However, in a taxonomy of BCTs that was created
specifically for physical activity and dietary interventions, Michie et al. (2011) point out that stress management techniques do not target the desired behavior directly but aim to facilitate behavioral performance by reducing stress and anxiety.
Since stress is inherent in IBS, this study suggests that for IBS-diagnosed people, stress management can lower stress levels with regards to following the low FODMAP diet, thereby increasing one’s intention to initiate the diet. Stress management is a widely used term that lacks a clear homogenous definition. Driven by the high number of stress
management studies, Ong, Linden, and Young (2004) conducted a meta-analysis in search for an overarching definition. They found a large number of techniques, which they categorized into three groups. The first one contains imaginary, relaxation, and meditation techniques, the second group entails cognitive-behavioral strategies, and the last group exists of systematic approaches, which focus on altering factors external to the individual. Furthermore, they
found that in most cases, stress management is delivered in group form, with a length of 8-10 sessions, and containing multiple techniques. However, due to time constraints in the current study, stress management will refer to a short, one-time diaphragmatic breathing exercise.
Diaphragmatic breathing, or deep breathing, refers to a breathing technique whereby the abdomen expands, and the chest does not rise while breathing. Physiological effects of this technique that lead to reduced stress include decreased oxygen consumption, decreased blood pressure and heart rate, and increased activity in the parasympathetic nervous system, which is responsible for the stimulation of activities that occur when the body is at rest
(Varvogli & Darviri, 2011). Diaphragmatic breathing has been successfully used for multiple goals, among which are the management of male adolescent aggressive behavior (Gaines & Barry, 2008), the reduction of anxiety and asthma symptoms in children (Chiang, Ma, Huang, Tseng, & Hsueh, 2009), and the management of acute stressful tasks (Nogawa, Yamakoshi, Ikarashi, Tanaka, & Yamakoshi, 2007). Activities around the low FODMAP diet, such as the planning and preparation of meals, doing groceries, and eating out, are likely to be
experienced as stressful tasks, due to all the rules and restrictions that characterize the diet. As stress management has proven to help with the management of stressful tasks, this study proposes the following first hypothesis:
Hypothesis 1: Stress management positively influences intention to start the low FODMAP diet.
Self-efficacy
Bandura (1977) defined an efficacy expectation as “the conviction that one can successfully execute the behavior required to produce the outcomes” (p. 193). Together with this definition, he emphasized the difference between efficacy and outcome expectations. The latter refers to what people think doing the behavior will lead to, which is different from convictions about one’s ability to perform the behavior. Furthermore, Bandura explains that
the strength of self-efficacy is likely to affect whether people will perform a certain behavior, as people tend to not take action when they feel that they lack the capability, but willingly take action when they are sure of their coping skills. Therefore, efficacy expectations are a major determinant of behavior, as are the amount of effort a person wants to put in, and how long he or she will keep doing the behavior. However, expectation is not a sole determinant of behavior, since people need the skills and the incentives to perform a behavior.
Similarly, Fishbein and Cappella (2006) described self-efficacy as a function of underlying beliefs about specific barriers to behavioral performance. The more one believes that he or she is able to perform the behavior, even when faced with specific obstacles or barriers, such as time or money constraints, the stronger is one’s self-efficacy towards performing the behavior in question. Fishbein and Cappella distinguish two types of beliefs underlying self-efficacy. Firstly, control beliefs refer to beliefs about specific factors that a person might perceive as barriers to performing a behavior. Secondly, perceived power refers to the ‘weight’ of each control belief factor in performing the behavior. For example, bad weather might be a control belief factor when the behavior is outside exercise. While rain can be perceived as a barrier to going outside for exercise, it might be that a person still decides to perform the behavior when bad weather does not weigh up to not doing the behavior.
Building forth on Bandura’s notion of self-efficacy in a health behavior context, Prochaska and Velicer (1997) integrated the concept in a transtheoretical model, describing self-efficacy as “the situation-specific confidence people have that they can cope with high risk situations without relapsing to their unhealthy or high risk habit” (p. 40). The
transtheoretical model was developed as early as 1977 and since then refined based on multiple theories of psychotherapy (Prochaska & Norcross, 2018). The model focuses on behavior change as a process of progressing through a series of stages. Different stages are described, starting with the precontemplation stage, in which people do not intend to change
their behavior and are often unaware that their current behavior is problematic. Second is the contemplation stage, in which people come to realize that their behavior is problematic, and therefore start looking at pros and cons about their future behavior. The third stage is the preparation stage, at which point people intend to change their behavior in the near future, and even start to take small steps towards a healthier behavior. The fourth stage refers to action, meaning that people have been taking active steps to change their problematic behavior to a healthier one. Finally, the maintenance stage consists of people who have been able to sustain their behavior change for at least six months and are still actively preventing relapse. When progressing through the stages of change, pros increase and cons decrease so that at the precontemplation stage, cons weigh out the pros, and vice versa from the preparation stage onwards. The role that self-efficacy plays in this model is that it increases with stage
progression (Nigg et al., 2011). For example, Shaver, McGlumphy, Gill, and Hasson (2019) studied physical activity and exercise behaviors and observed higher self-efficacy at higher stages of change. Following the idea that self-efficacy increases while progressing through the stages, it is expected that a certain amount of self-efficacy is needed to move to the next stage, which is key in behavior change interventions.
Prestwich et al. (2014) found that self-efficacy is an important determinant for dietary behavior. They did a meta-analysis of dietary interventions in order to identify the most effective BCTs to increase self-efficacy and found strong evidence for stress management, which was consistently associated with self-efficacy effects throughout their analyses. For other BCTs, Prestwich et al. found weaker or no evidence regarding effects on self-efficacy. Based on these findings and the previous discussion, this study argues that stress management increases self-efficacy, which helps people progress through the stages of change, which ultimately enhances intention. This idea results in the following hypothesis:
Hypothesis 2: Self-efficacy explains the effect of stress management on intention to start the low FODMAP diet.
Modality
Digital platforms and applications are characterized by the ability to present content in many different ways, for example by text, video’s or podcasts. The cognitive theory of multimedia learning assumes that humans process visual/pictorial and auditory/verbal information through separate channels, which both have limited processing capacity (Mayer, 2002). Multimedia learning starts with a person selecting words and images from presented material, that are relevant to him or her. Processing of selected content includes organizing the words and images into verbal or visual representations and integrating these
representations with prior knowledge. Pictures are being processed mainly in the visual/pictorial channel and spoken words by the auditory/verbal channel. However, the processing of words on paper or screen initially takes place in the visual/pictorial channel, but then moves to the auditory/verbal channel. Based on this knowledge, Mayer (2002) came up with the multimedia principle, which states that people learn better from a combination of words and pictures than from words alone. This can be explained by the idea that people who are presented with words alone will create a verbal mental model, but not a pictorial mental model, which would be the case if the words were supplemented by pictures. When both verbal and pictorial mental models are created, people can make connections between the two models, leading to a more extensive understanding of the material.
This multimedia principle was supported by a study in which students performed better on retention and transfer tests after being presented with text and illustrations or narration and animation than did students who were presented with text or narration alone (Mayer). Not only Mayer confirmed his own theory, as multiple other studies showed evidence for the effectiveness of combining the auditory and sensory modes (Brünken &
Leutner, 2001; Mousavi, Low, & Sweller, 1995; Tindall-Ford, Chandler, & Sweller, 1997). Therefore, this study distinguishes two instruction modalities for the stress management exercise, of which the first is text (verbal) and the second is a combination of text and animation (verbal and pictorial). It is expected that the combining of sensory modes contributes to a better understanding of the instructions, and therefore a better execution of the exercise. Better execution of the exercise should enhance the effects of stress
management. Therefore, this study proposes the following two hypotheses:
Hypothesis 3a: The effect of stress management on self-efficacy is stronger when the stress management exercise is instructed in text and animation, than in text alone.
Hypothesis 3b: The effect of stress management on intention to start a low FODMAP diet is stronger when the stress management exercise is instructed in text and animation, than in text alone.
Methodology Participants
The target population of this study consists of IBS-diagnosed adults, who are not on a low FODMAP diet at the time of participating in the study. This is because the dependent variable is intention to start the low FODMAP diet, and the diet is specifically made for people suffering from IBS. Due to money and time constraints, convenience sampling was used in order to gather a large sample in a short amount of time. Different IBS organizations were approached online to help distribute the survey, of which one organization decided to help. The Dutch Prikkelbare Darm Syndroom Belangenvereniging (PDSB) posted a link to the survey on their website and on their Facebook page. Because of their Dutch-speaking audience, the survey was translated to Dutch before distribution. In total, a number of 155 people started the survey, of which 64 did not finish, and 12 individuals did not match the respondent conditions, because they were either too young, not diagnosed with IBS, or on a low FODMAP diet. Of the remaining 79 participants, the major part was female (89.9%), compared to male (7.6%), and 2 persons answered the gender question with ‘Other’. Ages ranged from 18 to 100 (M = 41.19, SD = 16.82), and respondents resided either in the Netherlands (88.6%), or in Belgium (11.4%). More than a third of the respondents (34.2%) answered to have tried a low FODMAP diet in the past. Of this group, most people answered that when they were on the diet, their symptoms got ‘much better’ (40.7%), ‘a little better’ (18.5%), or ‘about the same’ (18.5%).
Procedure
Data collection. Data collection took place from May 18 until June 6, 2019, through an online self-completion questionnaire that was distributed online by the PDSB. The link to the survey was preceded by a brief text explaining that the study is carried out by a student of the University of Amsterdam and that people could participate if they were IBS-diagnosed
and not currently following a low FODMAP diet. The survey included randomization into a treatment or control condition, which was presented in either text or text and animation. The manipulation was followed by a posttest. In other words, this study had a 2x2 between-subjects design. A pretest was not included, because of its risk of pretest sensitization, which could cause participants to become aware of the aim of the study. Furthermore, the effects of stress management on self-efficacy have been demonstrated already in other studies
(Prestwich et al., 2014). Halfway data collection, one board member of the PDSB did not approve with the information that was provided in the control conditions. A short text or video presented eight foods to avoid with IBS, but this was not in line with the information that the PDSB provides. Therefore, the survey was adjusted by replacing both control
conditions for one neutral control sentence, to be able to continue data collection as quickly as possible. The original version of the survey is demonstrated in Appendix B, and the new control sentence will be stated in the manipulation section. Datasets from the two surveys were merged together, however, they also still exist as two separate datasets for the sake of comparison. The response time for the surveys was Mdn = 5.62 minutes.
Survey structure. After an informed consent page, eligibility of participants was checked with a question about their age, and questions asking them whether they are diagnosed with IBS and whether they follow a low FODMAP diet. If one or more of the answers did not match the conditions, the respondent was redirected out of the survey with a message stating “Unfortunately, one or more of your answers do not match the participant requirements for this study. Only adults who are diagnosed with Irritable Bowel Syndrome, and are not currently on a low FODMAP diet, can take part in this study”. After the
eligibility questions, participants were asked about their gender and country of residence, followed by the question of whether they had tried a low FODMAP diet before. If they answered ‘yes’, they also got a follow-up question asking about the effect of the diet on their
symptoms. Subsequently, participants were randomly assigned to one of two treatment conditions or a control condition. After the treatment or control condition, participants were provided a link to a flyer with information about the low FODMAP diet, which was made especially for this study. The flyer can be found in Appendix A. Afterwards, two scales measured self-efficacy towards the diet and intention to start the diet within a month from now. In the end, participants were thanked for their time spent on the survey and shortly debriefed about the aim of the study. The complete survey can be found in Appendix B.
Manipulation. In the treatment conditions, participants were asked to slowly breathe in and out five times, while focusing on expanding the belly rather than the chest. The instructions were given either in text (n = 26) or in a video with text and animation (n = 16). The original control conditions were also in both text (n = 9) and video (n = 10) format and consisted of a list of eight foods that were best to avoid by people with IBS. When the information provided in the control conditions was no longer tolerated, instead of the original information, they were shown the following text: “Good job, you are already halfway
through! On the next page you will be asked to read a flyer with information about the low FODMAP diet, followed by the final questions” (n = 18).
Self-efficacy and intention scores from participants in the new control condition were compared with the scores from participants in the control condition in text, to determine whether the two conditions could be combined. An independent samples t-test was conducted to test for differences between the two conditions. Firstly, Levene’s test indicated no
homogeneity of variance for intention to start the low FODMAP diet, F (25) = 4.71, p = .04, and the t-test revealed no significant difference between the two conditions for intention, t (12) = 0.14, p = .89. Secondly, equal variances were assumed for self-efficacy based on Levene’s test, and a significant difference was found between the two conditions, t (25) = 2.83, p = .009, 95% CI [0.49, 3.12], d = 1.12. Participants in the control condition in text (M
= 5.24, SD = 1,75) scored significantly higher on self-efficacy than participants in the
condition with the new control sentence (M = 3.44, SD = 1.47). Therefore, data from the two conditions were not combined, and cases in the new condition were not used for testing the hypotheses.
Ethics. At the start of the survey, respondents were shortly introduced to the study, including a description of what they could expect from the survey, and a brief statement about the aim of the study, which was stated as follows: “The goal of this research is to generate insight into the low FODMAP diet in relation to IBS”. This statement was deliberately kept short and undetailed to prevent biased answers to the questions. Furthermore, participants were explained the terms of their participation in the study, including anonymity and the right to withdraw their permission up to seven days after participating. Finally, contact information was provided of the researcher and the ethical commission, in case participants have questions or complaints. Participants had to agree to the terms in order to continue with the survey. After the survey, participants were thanked for their cooperation, and a more detailed aim of the study was provided: “The current study focuses on the intention of IBS sufferers to start a low FODMAP diet, and aims to determine whether stress management and self-efficacy affect this”.
Measures
Intention. Intention to start the low FODMAP diet within the next month represented the dependent variable in this study. The variable was measured in the form of a 7-point Likert scale (1 = strongly disagree, 7 = strongly agree), with one item stating, “I intend to start a low FODMAP diet within a month from now”, which was based on Ajzen’s (2019) theory of planned behavior questionnaire construction. Table 1 below presents an overview of how participants answered.
Table 1
Intention to start low FODMAP diet
n %
Strongly disagree 27 34.2 %
Disagree 20 25.3 %
Somewhat disagree 2 2.5 %
Neither agree nor disagree 13 16.5 %
Somewhat agree 12 15.2 %
Agree 4 5.1 %
Strongly agree 1 1.3 %
Self-efficacy. Self-efficacy towards the low FODMAP diet was presented in this study as a mediator of the proposed effect of stress management on intention to start the low FODMAP diet. Self-efficacy was measured by a 20-item, 7-point Likert scale (1 = not certain at all, 7 = highly certain), in which participants were asked how certain they were that they could stick to a low FODMAP diet in a number of situations that could make it
hard. Examples of items are “When feeling restless or bored”, “When eating at a friend’s house for dinner”, “When visiting a city and needing a quick meal”, and “When faced with appealing high FODMAP foods in the supermarket”. The scale was adjusted from Bandura’s (2006, p. 322) self-efficacy to regulate eating habits scale. The original scale has 30 items, but for the current study this was shortened to 20, to prevent the survey from becoming too long. The 10 items that were deleted, were selected based on the number of similar items in the list. Furthermore, the words “high fat foods” on the original scale were replaced by “high FODMAP foods”. Additionally, answer options for the original scale ranged from 0 to 100, but that was changed to a 7-point Likert scale, which is more mobile friendly. A total
self-efficacy score was calculated by taking the average of the scores for all the 20 items ( = .97, M = 3.94, SD = 1.64).
Control variables. Besides self-efficacy and intention, a few variables were
measured to test for correlation with the dependent and mediator variables. Age and gender were measured, but also whether participants had tried the low FODMAP diet in the past, and what the effect had been on their symptoms. First, the question was asked, “Have you ever tried a Low FODMAP Diet before to reduce your IBS symptoms?”, which could be answered with yes or no. When participants answered ‘yes’, they got the follow-up question, “What was your experience with the low FODMAP diet? Please indicate the effect of the diet on your symptoms. When on the low FODMAP diet, my symptoms got...", with answer options ranging from ‘much worse’ to ‘much better’.
Results Randomization
In order to check for effectiveness of the randomization into one of the four
conditions, the variables age, gender, and prior experience with the low FODMAP diet were tested. A one-way analysis of variance was carried out for the variable age. Levene’s test showed that the variances of the four conditions were equal, F (3, 57) = 2.28, p = .09. No statistically significant difference was found between the four groups for age, F (3, 57) = 0.88, p = .46. Furthermore, no statistically significant difference was found for gender, 2 (6, N = 61) = 2.46, p = .87, and prior experience with the diet, 2(3, N = 54) = 2.04, p = .56. Covariates
The control variables measured in this study were tested for correlation to self-efficacy and intention. As a major part of the sample exists of females (89.9%), gender was excluded from correlation testing because the sample sizes of the groups differ too much. Results of an independent samples t-test show a significant difference in self-efficacy scores between
people who had tried the low FODMAP diet before (M = 4.98, SD = 1.75) compared to people who had not (M = 3.38, SD = 1.35), t (68) = 4.31, p < .001, 95% CI [0.86, 2.34], d = 1.02. Other control variables did not correlate to self-efficacy, and none of the control variables correlated to intention to start the low FODMAP diet.
Hypotheses Testing
Stress management and intention. The first hypothesis proposed that stress
management positively influences intention to start the low FODMAP diet. In Table 2 below, Table 2
Intention scores comparing stress management and control conditions Stress management Control
Strongly disagree 16.2% 57.9%
Disagree 31.0% 5.3%
Somewhat disagree 0.0% 0.0%
Neither agree nor disagree 19.0% 15.8%
Somewhat agree 14.3% 15.8%
Agree 7.1% 5.3%
Strongly agree 2.4% 0.0%
Total 100% 100%
data for intention to start the low FODMAP diet is shown, comparing the stress management and control conditions. The intention statement was, “I intend to start a low FODMAP diet within a month from now”, and the table shows that major part of participants in the control conditions answered to strongly disagree (57.9%), compared to participants in the stress management conditions (16.2%). Furthermore, more people in the treatment conditions answered agree or strongly agree (9.5%), compared to the control conditions (5.3%). In order to test for an effect, a linear regression analysis was conducted. However, the scatterplot of
standardized predicted values showed that the homoscedasticity assumption for regression was not met. Therefore, the regression model could not be used to predict intention.
Naturally, no significant results were found, F (1, 59) = 1.12, p = .29, meaning that the first hypothesis was not supported.
Self-efficacy. The second hypothesis proposed that self-efficacy mediates the effect of stress management on intention, so that stress management increases self-efficacy, which in turn increases intention to start the low FODMAP diet. Although the first hypothesis was not supported, self-efficacy was tested for a mediation effect through an analysis with Hayes’ (2017) PROCESS, model 4. The results show that the model is not a good fit for the data to predict self-efficacy by stress management, F (1, 59) = 1.57, p = .22, or to predict intention by stress management and self-efficacy, F (2, 58) = 0.89, p = .41. Furthermore, no significant mediation effect was found, b = -0.07, 95% BCa CI [-0.39, 0.16]. As none of the previous results were significant, both complete and partial mediation were ruled out (Baron & Kenny, 1986). Controlling for the variable that measured whether participants had tried the low FODMAP diet or not, did not significantly change any of the effects above. Therefore, hypothesis 2 was not supported.
Modality. Hypothesis 3a proposed that the effect of stress management on self-efficacy is stronger for participants in the stress management condition with text and
animation, compared to the text only condition. However, the data shows that self-efficacy is a little bit lower in the text and animation condition (M = 4.07, SD = 1.55), compared to the text only condition (M = 3.66, SD = 1.37). A regression analysis was carried out to test for moderation, using Hayes’ (2017) PROCESS, model 1. Results show that the model is not a good fit for the data to predict self-efficacy, F (3, 57) = 2.00, p = .12, which is why hypothesis 3a was rejected. Finally, hypothesis 3b proposed that the effect of stress management on intention is higher for participants in the stress management condition with text and
animation, compared to text only. Again, a regression analysis was carried out, and the results show that the model is not a good fit for the data, meaning that intention cannot be predicted by the model, F (3, 57) = 0.65, p = .59. Therefore, hypothesis 3b was also rejected.
Discussion and Conclusion
The current study explored whether stress management in the form of a one-time diaphragmatic breathing exercise contributes to IBS-diagnosed people’s self-efficacy towards the low FODMAP diet, and their intention to initiate the diet. This research objective was based on the idea that limitations and difficulties of the diet are likely to raise barriers, which prevent people from wanting to initiate the diet to reduce their IBS symptoms. Intention was chosen to be the dependent variable because it has proven to be a strong predictor for
behavior (Fishbein, 2000), and studying behavior itself would take more measurements over a longer period of time. Stress management has helped for many causes, among which the management of acute stressful tasks. Low FODMAP diet-related activities are likely to be perceived as stressful tasks, because of the restrictions that come with the diet. Consequently, stress management was expected to lower diet-related stress and as a result enhance intention to initiate the diet. Self-efficacy was identified to predict intention to start the low FODMAP diet, as many studies on self-efficacy confirm that it is a key determinant of behavior
(Bandura, 1977; Fishbein & Cappella, 2006), including dietary behavior specifically
(Prestwich et al., 2014). Also, strong effects of stress management on self-efficacy have been found (Prestwich et al.), which is why self-efficacy was tested for a mediating effect on the proposed effect of stress management on intention to start the low FODMAP diet.
Furthermore, this study aimed to find out whether the effects of the stress management exercise differ when the instructions are in different modalities, namely text and animation, or text alone. This was hypothesized based on Mayer’s (2002) multimedia principle, which states that instructions combining the visual and auditory modes are more effective than
instructions targeting only one of both modes. This was supported by other studies as well (Brünken & Leutner, 2001; Mousavi, Low, & Sweller, 1995; Tindall-Ford, Chandler, & Sweller, 1997).
The current study aimed to contribute to the literature in two ways. Firstly, it was explored whether self-efficacy is a good determinant of dietary behavior in the IBS context, which differs from regular dieting in that the low FODMAP diet’s main goal is symptom reduction, opposed to weight reduction. Secondly, the multimedia principle was tested for a different goal than the transfer and retention of information, namely for an effect on the execution of a stress management task.
Based on the study’s main objectives, four hypotheses were proposed and empirically tested. Firstly, the expected effect of stress management on intention to start a low FODMAP diet was not confirmed. Although it seemed like participants in the treatment conditions agreed more with the intention statement than participants in the treatment conditions, no statistically significant effect was found. This means that the stress management exercise could not predict people’s intention to start the low FODMAP diet, let alone influence. Secondly, the expected mediating effect of self-efficacy on the hypothesized effect of stress management on intention was also not confirmed by this study. Results showed no
significant effects, meaning that stress management and self-efficacy could not be used to predict intention to start the low FODMAP diet. Finally, different instruction modalities of the stress management exercise were expected to differ in effect for self-efficacy and intention. Both hypotheses were not supported by the data, meaning that no significant differences were found in self-efficacy or intention between participants in the text and animation condition, compared to the text only condition. One unexpected result derived from testing the new control condition for differences with the original control condition in
text. Participants in the new control condition scored significantly lower on self-efficacy than participants in the control condition in text.
Theoretical Implications
The results of the current study contradict Prestwich et al.’s (2014) evidence that stress management enhances self-efficacy, and the study of Nogawa, Yamakoshi, Ikarashi, Tanaka, & Yamakoshi (2007), who found that diaphragmatic breathing was effective in the management of acute stressful tasks. This could possibly be caused by the practical
application of stress management as a BCT in this study. While the term stress management is used for a wide variety of techniques, Ong, Linden, and Young (2004) found that most treatments consist of 8-10 group sessions, in which multiple techniques are being used. The exercise in this study had to be online and without human-to-human interaction, because of the nature of data collection. Therefore, the exercise was just one, individual session with only one stress management technique. Furthermore, diaphragmatic breathing is usually taught in person by a trained therapist and needs practice to get the hang of it (Varvogli & Darviri, 2011). This could explain why participants possibly did not use the right technique and thereby minimized the potential effects. Another reason for the results could be that stress management is not the right method for people with IBS after all. This would mean that a solution must be found in other BCT’s.
This study’s results also contradict the outcomes of studies supporting the multimedia principle (Mayer, 2002; Brünken & Leutner, 2001; Mousavi, Low, & Sweller, 1995; Tindall-Ford, Chandler, & Sweller, 1997). Logical explanations can be found in the execution of the study. In the case of the breathing exercise, the instructions were not complex or long, which might have made it unnecessary to add an extra sensory mode. This might be the reason why no difference in effect was found between the two modalities.
Practical Implications
Based on this study’s results, a short, one-time breathing exercise will not help people with IBS to reduce stress and initiate the low FODMAP diet. A possible solution could be to provide IBS-diagnosed people with a workshop in stress-management where they get
professional training in different stress management exercises. Afterward, participants should keep doing the exercises regularly to obtain the most effects. Such a workshop could even be tailored to IBS and the low FODMAP diet specifically, to gain a better understanding of what to do in stressful diet-related situations, such as meal planning or grocery shopping.
Limitations of the Study
There are a few limitations to this study that should be considered in future research attempts. The sample size of 79 was not as large as desired, mainly because of the large number of outages. Many participants started the survey but quit halfway. This problem could have possibly been prevented by a raffle, whereby people have the possibility to win money or a gift card, simply by participating in the study. Furthermore, the content of the control condition was changed halfway data collection, because the information provided was no longer accepted on the website and Facebook page of the PDSB. This was because the information in the control condition about foods to avoid with IBS was not in line with the information the PDSB provides. This change affected the internal validity of the study, as the control condition was not the same for everyone. The different control conditions were tested for differences, with the result that the new control condition was excluded from the analyses, resulting in a decrease of the sample to 61. A small sample size threatens the reliability of the study, since the variability is higher, leading to biased results.
Suggestions for Future Research
In order to find out the possible benefits of stress management with regards to the low FODMAP diet, future research could entail a study over a longer period of time, in which
stress management takes place in groups with multiple sessions (Ong, Linden, & Young, 2004), and self-efficacy and intention to start the diet are measured multiple time. Another suggestion for future research would be a study on modality and stress management, including more complex instructions, and a task afterward in which retention of the information is measured. This way, the effect of modality can be measured better.
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APPENDIX B
Version A
Dear reader,
I would like to invite you to participate in a research study to be conducted under the auspices of the Graduate School of Communication, a part of the University of Amsterdam. The title of the study for which I am requesting your cooperation is ‘Irritable Bowel Syndrome and the low FODMAP diet’. In the online survey, you will be asked to participate in a short task, and you will be presented with some information on the low FODMAP diet. In addition, several questions will be asked about potential difficulties of this diet. Only persons
diagnosed with IBS who are not on a low FODMAP diet at this moment, may participate in this study. The goal of this research is to generate insight into the low FODMAP diet in relation to IBS.
The study will take about 10 minutes. As this research is being carried out under the responsibility of the ASCoR, University of Amsterdam, I can guarantee that:
1) Your anonymity will be safeguarded, no IP addresses will be collected, and your personal information will not be passed on to third parties under any conditions, unless you first give your express permission for this.
2) You can refuse to participate in the research or cut short your participation without having to give a reason for doing so. You also have up to 7 days after participating to withdraw your permission to allow your answers or data to be used in the research.
3) Participating in the research will not entail your being subjected to any appreciable risk or discomfort, the researchers will not deliberately mislead you, and you will not be exposed to any explicitly offensive material.
4) No later than five months after the conclusion of the research, we will be able to provide you with a research report that explains the general results of the research.
For more information about the research and the invitation to participate, you are welcome to contact me, Eva Dambrink, at any time at eva.dambrink@student.uva.nl.
Should you have any complaints or comments about the course of the research and the procedures it involves as a consequence of your participation in this research, you can contact the designated member of the Ethics Committee representing ASCoR, at the
following address: ASCoR Secretariat, Ethics Committee, University of Amsterdam, Postbus 15793, 1001 NG Amsterdam; 020‐525 3680; ascor‐secr‐fmg@uva.nl.
Any complaints or comments will be treated in the strictest confidence.
I hope that I have provided you with sufficient information. I would like to take this opportunity to thank you in advance for your assistance with this research, which I greatly appreciate. Kind regards,
Page Break
I hereby declare that I have been informed in a clear manner about the nature and method of the research, as described on the previous page.
I agree, fully and voluntarily, to participate in this research study. With this, I retain the right to withdraw my consent, without having to give a reason for doing so. I am aware that I may halt my participation in the experiment at any time.
If my research results are used in scientific publications or are made public in another way, this will be done such a way that my anonymity is completely safeguarded. My personal data will not be passed on to third parties without my express permission.
If I wish to receive more information about the research, either now or in future, I can contact Eva Dambrink at eva.dambrink@student.uva.nl. Should I have any complaints about this research, I can contact the designated member of the Ethics Committee representing the ASCoR, at the following address: ASCoR secretariat, Ethics Committee, University of Amsterdam, Postbus 15793, 1001 NG Amsterdam; 020‐ 525 3680; ascor‐secr‐fmg@uva.nl. I understand the text presented above and agree to participate in the research study.
o
Yeso
NoEnd of Block: Informed consent Start of Block: Eligibility check
What is your age?
________________________________________________________________
Have you been diagnosed with Irritable Bowel Syndrome?
o
YesAre you currently on a Low FODMAP Diet?
o
Yeso
Noo
I'm not familiar with the Low FODMAP DietPage Break
End of Block: Eligibility check
Start of Block: Demographics
What is your gender? ▼ Male ... Female
In which country do you currently reside? ▼ Afghanistan ... Zimbabwe
Display This Question:
If Are you currently on a Low FODMAP Diet? != I'm not familiar with the Low FODMAP Diet
Have you ever tried a Low FODMAP Diet before to reduce your IBS symptoms?
o
Yeso
NoDisplay This Question:
If Have you ever tried a Low FODMAP Diet before to reduce your IBS symptoms? = Yes
What was your experience with the low FODMAP diet? Please indicate the effect of the diet on your symptoms.
"When on the low FODMAP diet, my symptoms got..."
o
Much bettero
Moderately bettero
Slightly bettero
About the sameo
Slightly worseo
Moderately worseo
Much worseEnd of Block: Demographics
Start of Block: Condition 1: treatment + text
Please follow the instructions below, while focusing on expanding and contracting the belly rather than the chest.
Note: as the outcomes of this study are important for people suffering from IBS, please take your time for this exercise.
Slowly:
Breathe in.... Breathe out....
Breathe in.... Breathe out....
Breathe in.... Breathe out....
Breathe in.... Breathe out....
Breathe in.... Breathe out....
End of Block: Condition 1: treatment + text Start of Block: Condition 2: control + text
Please read the information below, in which 8 foods are discussed that should be avoided with IBS.
Note: as the outcomes of this study are important for people suffering from IBS, please take your time to read through the information.
8 foods to avoid with IBS:
1. Broccoli - broccoli is high in fiber, but it can cause painful gas and bloating. If you don't want to give it up completely, try lightly steaming broccoli, instead of eating it raw.
2. Cauliflower - like broccoli, cauliflower can be an IBS trigger food as well. If you're using it to replace white starch like rice and potatoes, try switching to brown rice or quinoa for a less starchy, bloat free option.
3. Green pepper - Green peppers are though to digest, so they can cause
uncomfortable bloating and stomach pain. Instead, try red peppers or ripened green peppers for easier digestion.
4. Beans - Full of protein and fiber, beans can cause bloating for those with IBS, which is a good reason to limit them in your diet, despite their nutritional benefits.
5. Butter - Fatty foods can also cause unpleasant IBS symptoms. That's why cooking with butter and loading it onto vegetables can spell trouble for those prone to gassiness.
6. Lentils - Lentils are another legume that can be difficult to digest, and unfortunately, they are a hidden ingredient in many soups and meat alternative products.
7. Soft cheese - The worst cheese offenders are the creamy cheeses, such as brie and mascarpone. If you suffer from IBS, try hard cheeses like Parmesan and Swiss instead.
8. Milk & cream - Steer clear of milk and cream products that cause unpleasant IBS symptoms. Both can spell double trouble if you also suffer from lactose intolerance.
End of Block: Condition 2: control + text Start of Block: Condition 3: treatment + video
Please follow the instructions in the video below, while focusing on expanding the belly rather than the chest.
Note: as the outcomes of this study are important for people suffering from IBS, please take your time for this exercise.
End of Block: Condition 3: treatment + video Start of Block: Condition 4: control + video
Please watch the video below, in which 8 foods are discussed that should be avoided with IBS.
Note: as the outcomes of this study are important for people suffering from IBS, please take your time to watch the video.
End of Block: Condition 4: control + video Start of Block: Info on LFD + measures
When you click on the link below, a flyer on the Low FODMAP Diet will open in a new window. Please take a look at this flyer to learn about the Low FODMAP Diet.
Flyer
Page Break
A number of situations can make it hard to stick to a low FODMAP diet. How certain are you that you can stick to a low FODMAP diet in the following situations, if you were to start the diet as of tomorrow?
1 Not certain at all 2 3 4 Moderately certain 5 6 7 Highly certain When feeling restless or bored
o
o
o
o
o
o
o
During holiday timeso
o
o
o
o
o
o
When feeling upset or tense over job-related mannerso
o
o
o
o
o
o
When eating at a friend's house for dinnero
o
o
o
o
o
o
When preparing meals for otherso
o
o
o
o
o
o
When angry or annoyedo
o
o
o
o
o
o
When very hungryo
o
o
o
o
o
o
When depressedo
o
o
o
o
o
o
When you want to sit back and enjoy foodo
o
o
o
o
o
o
When lots of high FODMAP food is available in the houseo
o
o
o
o
o
o
When someone offers you high FODMAP foods
o
o
o
o
o
o
o
When feeling a strong urge to eat foods high in FODMAP's that you likeo
o
o
o
o
o
o
When eating out with others and they are ordering high FODMAP mealso
o
o
o
o
o
o
When at parties where a lot of appetizing high FODMAP food is servedo
o
o
o
o
o
o
When visiting a city and needing a quick mealo
o
o
o
o
o
o
When visiting a city and wanting to experience the local food and restaurantso
o
o
o
o
o
o
Holidays and celebrations where high FODMAP foods are servedo
o
o
o
o
o
o
When upset over family matters
o
o
o
o
o
o
o
When you have to prepare your own mealso
o
o
o
o
o
o
When faced with appealing high FODMAP foods in the supermarketo
o
o
o
o
o
o
Page BreakPlease indicate to what extent you agree with the following statement about you: Strongly disagree Disagree Somewhat disagree Neither agree nor disagree Somewhat agree Agree Strongly agree "I intend to start a low FODMAP diet within a month from now"
o
o
o
o
o
o
o
End of Block: Info on LFD + measures
We thank you for your time spent taking this survey. Your response has been recorded.
The current study focuses on the intention of IBS sufferers to start a Low FODMAP Diet, and aims to determine whether stress management and self-efficacy affect this.
For questions or more information about the study, please contact me via eva.dambrink@student.uva.nl
