Lupine Publishers | Scholarly journal of Food and Nutrition
Abstract
Background: University students’ encounter environmental changes which
exerts mixed perceptions on sufficiency of their diets.
Objective: This cross-sectional study determined the influence of
psychosocial factors influencing optimal dietary intake of university students.
Methods: This was conducted from August to November 2017 within 5
Kenyan universities purposively sampled. Stratified sampling was utilized to
obtain 230 respondents. Quantitative data was collected where exploratory
factor analysis tested dimensionality of questions, while skewness and kurtosis
assessed normality of data. Structural equation modelling determined predictive
power of latent variables.
Results: The model fitted data acceptably well; P<0.001, Tucker
Lewis index =0.93, comparative fit index =0.95, root mean square error of
approximation =0.090, Hoelter critical N (0.01=230], with optimal dietary
intake. Regression weights showed predictive power for student’s attitude
(β=0.68, P<0.01), subjective norm (β=0.36, P<0.05), perceived behavioural
control (β=0.34, P<0.05) towards intention (β=0.95 P<0.001).
Conclusion: Student’s attitude was a significant factor in improving
and upholding optimal dietary intake.
Keywords: Optimal dietary intake; Psychosocial factors; University
students; Theory of planned behaviour
Introduction
Sub-optimal dietary habits are among
the major risk factors for obesity, undernourishment, micro-nutrient
deficiencies and associated metabolic conditions, particularly if adopted
during early adulthood [1,2]. This is becoming more prevalent across all age
groups where traditional healthy diets are being progressively replaced by more
westernized dietary patterns [3]. University students seem to be the most
affected by this nutrition transition [4]; studies have shown that young adults
living away from home to attend university, experience numerous health-related
behavioural changes, including the adoption of unhealthy dietary habits [5- 7].
These behaviours are mostly attributed to drastic changes in the environment
and resources available, frequent exposure to unhealthy foods and habits. This
leads to higher consumption of energy-dense foods and low intake of
nutrient-dense foods in addition to frequent skipping of meals. Nutritionists
and dieticians’ support have been reported to be an essential motivational
factor in promotion of optimal dietary habit across populations of all age
groups; however, evidence suggests this is not basically the case for
university students.
For university students to be
inspired to practice healthy dietary habits, the optimal balance between
factors that manipulate their cognitive and experiential aspects must be achieved.
These cognitive and experiential aspects are the psychosocial factors that
determine student’s attitude, subjective norm and perceived behavioural control
towards intention to practice healthy behaviour in this case optimal dietary
intake. Intention is a significant predictor of dietary intake, which can be
optimal or suboptimal. Studies have described many factors associated with the
intention to practice optimal dietary intake amongst university students. These
factors include environmental, socio- demographic and behavioural that
determines students’ decision to optimal dietary intake [8-10]. However, there
is limited information on psychosocial factors which include attitude,
subjective norm and perceived behavioural control in association to practice of
optimal dietary intake [11]. Thus, this current study aimed at revealing the
influence of student’s attitude, subjective norm, perceived behavioural control
on their intention to practice optimal dietary intake.
Methods and Data
Study
Framework
The study adapted Ajzen’s Theory of
Planned Behaviour (TPB) model [12] (Figure 1) to fit psychosocial factors that
influence optimal dietary intake of university students. The TPB model works on
the basis that the approach to target behaviour is to assess behavioural
intention, which in turn is seen to be an operation of 4 exogenous variables:
attitudes, subjective norm, perceived control and intention. In this context,
students’ attitude was the certainty about likely outcomes of optimal dietary
intake multiplied by evaluation of these outcomes (behavioural beliefs).
Subjective norm was the belief of the students over important people in his/her
life that may or may not have influenced them to optimally feed multiplied by
the level of compliance to such influences (normative beliefs). Perceived
behavioural control was viewed as control factors to promote or inhibit the
students to optimally feed multiplied by the power they had over those factors
(control beliefs). Perceived behavioural control was measured both directly and
indirectly since optimal dietary intake was not under completely volitional
control. Therefore, students’ attitude and subjective norm were posited to have
influenced optimal dietary intake indirectly through intention.
While perceived behavioural control
both indirectly and directly manipulated optimal dietary intake. Intention was
described as a behavioural tendency that captured the motivational factors that
had an impact on behaviour (optimal dietary intake). The latent variables were
endogenous since they depend on observed variables to be measured, whereas observed
variables were exogenous since they are independent variables. When a variable
is believed to “cause” another variable, the relationship between the variables
is shown as a directed arrow, from cause to effect. Whether one variable
“causes” another is an assumption that the researcher makes and only data can
reveal. Co variation between 2 variables is shown as a 2-headed arrow
connecting the variables. As a theory of competency and mastery, psychosocial
factors influencing students’ optimal dietary intake describes that initiation
and persistence towards it are determined primarily by students’ optimal
dietary intake cognitive judgments and expectations.
To comprehend optimal dietary intake
using the TPB model [12], an elicitation study was initially conducted prior to
the current study to elicit salient beliefs on which exogenous variables are
based. This was then employed to construct a questionnaire, which was pretested
and used to assess the influence of these psychosocial factors on optimal dietary
of university students. Therefore, the Theory of Planned Behaviour model was
the theory of focus since it has the ability to distinguish between those who
perform and do not perform the behaviour under investigation [13]. Therefore,
by utilizing the TPB, one can gain an understanding of the behaviour [optimal
dietary intake] by tracing its determinants back to the underlying beliefs and
possibly further influence the behaviour by changing a sufficient number of
these beliefs [14]. A structural model was specified as per the objectives and
tested as a good fit for data obtained on optimal dietary intake.
Study
Area and Design
The study was conducted within 5
Public Kenyan Universities purposively selected with the aim that they had
operational human nutrition programme that emphasized the health benefits of
optimal dietary intakes. This cross-sectional study was conducted from August
to November 2017 amongst 230 randomly selected and stratified students
receiving education in a human nutrition related bachelor’s degree from the 5
universities. Permission was obtained from the School of Graduate Studies.
Ethical approval was given by National Council for Science and Technology.
Research authorization was granted by the respective administration of the 5
universities. We sought informed consent from the respondents who were informed
on the research procedures, details and assured of confidentiality.
Sample
Criteria and Sampling Techniques
Sampling procedures involved
selection of universities and respondents. Purposive sampling was used to
identify 5 Public Universities for the study with the target that they offered
Human Nutrition related bachelor’s degree programme and were accredited by their
regulator- Kenya Nutritionists and Dietetics Institute. Proportionate
stratified sampling was used to get the sample size of respondents from each
stratum of University A (46), University B (44), University C (50), University
D (48) and University E (42). Random sampling was then employed on each stratum
depending on its size to get the final study sample size of N=230. Sample
criteria included both males and females’ students pursuing a bachelor’s degree
in Human Nutrition. Participation in the study was voluntary although 4 % of
respondents dropped out of the study due to inevitable circumstances but were
immediately replaced through a random sampling procedure performed on eligible
participants. The respondents were not compensated for taking part in the study
but were highly appreciated and given a debriefing letter after completion of
the interview sessions.
Data
Collection Instrument
Data collection was conducted from
August to November 2017 by the main researcher and 5 trained research
assistants. A 7-point Likert-type scale optimal dietary intake questionnaire
was used to collect the quantitative data. Both convergent and divergent
validity were determined by comparing answers to each question measuring the
same concept, then by measuring this answer to the respondent’s response to a
question that asks for the exact opposite answer. Back-translation was also
done to check for reliability of the translation. The pretested questionnaire
was acceptable based on factor analysis criteria used and concepts of
measurements loading with communalities for each item being greater than 0.5.
This questionnaire was acceptable having confirmed adequacy of sample size
(N=230) using test of sphericity. The internal consistency estimates of the
various concepts, using Cronbach’s alpha, ranged from 0.64 to 0.89. The closer
the Cronbach’s alpha coefficient is to 1.0 the greater the internal consistency
of the items in the scale. George and Mallery’s rule of thumb was used to
classify the Cronbach’s alpha coefficients generated.
Statistical
Methods
Data was entered into SPSS version
15 to calculate for reliability tests where Cronbach’s alpha was used to assess
the consistency of the questions. The response for each question was
distinctive, and rotated component factors loading for each variable was
subjected to principal component analysis. George and Mallery’s [15] rule of
thumb was employed to categorize the average of communalities of student’s
attitude, subjective norm, perceived behavioural control and intention. To
establish whether the model nested based on TPB variables applied to optimal
dietary intake fitted the data acceptably well, structural equation modelling
using AMOS version 7 was conducted. Structural equation modelling was used to
determine the influence of student’s attitude, subjective norm, perceived
behavioural control and intention on optimal dietary intake. Intention was
assessed by the extent to which respondents were willing to practice optimal
dietary intake [eating a balanced diet, diet diversity & variety, and
sufficient diets]. Measurements of this was done using a Likert-type scale
ranging from 1 to 7, where 1 represented not at all and 7 represented very
much. The overall model fit was evaluated using χ2 (CMIN) and relative χ2
divided by degrees of freedom (CMIN/df), comparative fit index (CFI), the
standardized root means square error of approximation (RMSEA), Hoelter’s
critical N, and Bollestine bootstrap. CFI and Tucker– Lewis index (TLI) values
greater than 0.90 were considered satisfactory. RMSEA values less than 0.08
were considered satisfactory. CMIN/ df was regarded as fit when it ranged 3:1
and considered better when closer but not less than 1.0 Hoelter’s critical N
for significance levels of 0.05 and 0.01 were used where bootstrap samples were
set at 200.
Results
Influence
of Student Attitude, Subjective Norm, and Perceived Behavioural Control on
Intention to Practice Optimal Dietary Intake
It was found that the items
characterizing attitude, subjective norm and perceived behavioural control had
high regression weights approaching to 1.00. The relationships between observed
variables in the model (Figure 2) were significant. The goodness of fit was
statistically non-significant at the .01 level, but the model would be rejected
at the 0.05 level (χ2 = 620.1, df = 250, P = 0.12, χ2 / df = 2.30). Although
the χ2 was under the recommended 3:1 range indicating acceptable fit, after
significant modification indices were unassociated. Other fit indices (TLI =
0.93, CFI = 0.95, RMSEA =0.090) also showed a good model fit (Table 1).
Note: RMSEA=Root mean square
residual; CFI=Comparative fit index; CMIN/DF=Chi-square/degree of freedom; TLI=
TuckerLewis Index; χ²= Chi-square.
Hoelter’s critical N values
recommend that the model would have been accepted for lower limit at the .05
significance level with 200 cases, and the upper limit of N for the .01
significance level is 230 cases. The Bollen–Stine P =0.12 provided further
reassurance about the model fit among other global fit indices. The regression
weights (Figure 2) indicates that students’ attitude had a statistically
significant influence on optimal dietary intake through intention (β= 0.68,
P< 0.01, N=230). Indirect perceived behavioural control had a statistically
significant influence on optimal dietary intake through intention (β=0.64,
P<0.01, N=230). This was followed by subjective norm, which had a
statistically significant influence on optimal dietary intake through intention
(β= 0.52, P< 0.05, N=230). Intention was found to have the strongest
prediction for optimal dietary intake (β = 0.95 P< .001, N = 230). Direct
perceived behavioural control had the least influence on optimal dietary intake
(β = 0.12, P> 0.05, N =230).
Discussion
This study focused on examining
motivational beliefs [attitude, subjective norm and perceived behavioural
control] associated with students practice of optimal dietary intake of based
on the Theory of Planned Behaviour.
Influence of Student’s Attitude on
Optimal Dietary Intake The default model had significant influence and was
valued, since the forecasts supported the validity of the TPB model. The
concept of influence involved dietary intake that was retrospectively explained
by TPB, which allowed a prospective test of theoretical understanding. The
influence of students’ attitude, subjective norm, perceived behavioural control
and intention in extrapolating optimal dietary intake was tested. Standardized
regression weights in (Figure 2) indicated that more students placed a high
value on the health benefits of practicing optimal dietary intake (β = 0.68,
P< 0.01, N = 230). Positive attitudes are associated with supportive
significant others who motivated practice of optimal dietary intake [16].
Previously, revealed that associated health benefits were linked to practicing
optimal dietary intake which had an impact on the attitudes of young adults in
colleges. A recent study found that young adults, compared to middle-aged
adults, had lower perception regarding optimal diets and health, suggesting a
relatively low level of interest in health among young adults. Similarly,
previous studies found that reasons for sub optimal dietary intake amongst the
young adults were ‘poor attitudes’ and ‘wrong influence’. Thus, nutrition
education, accurate information and right influence should positively impact on
attitudes of students to practice optimal dietary intake based on one’s health
concerns. In this study, students’ attitude was perceived to be associated with
optimal dietary intake knowledge, influence of significant others and
self-efficacy of the student. This illustrates that attitude correlates with
other factors for it to be optimal. The current study established a
statistically significant correlation between students’ attitude and subjective
norm (r= 0.95, P= 0.001). The correlation between attitude and perceived behavioural
control was stronger, positive and statistically significant (r = 0.97, P=
0.001). Contrary students may have positive attitudes towards optimal dietary
intake although the obstacles they encounter surpass their ability to optimally
practice the behaviour.
Influence
of Student’s Subjective Norm on Optimal Dietary Intake
Subjective are the behavioural
standards that exist in a social group for what is considered correct and
appropriate behaviour [17], and they emerge from the shared practices and expectations
of the group members. Previous research has shown that, through changing
individual’ perceptions of existing social norms, various kinds of health
behaviours can be influenced, such as optimal dietary intake [18]. A student’s
decision to optimally feed is influenced by what is socially acceptable, open
to social and cultural influences. We examined normative influences in relation
to referents differing in social distance, including family members, friends,
colleagues and mass media. However, of particular interest in this study was
the detailed analysis of student’s perception of social pressure from
significant sources of reference and change in perception of these views in
relation to balanced diets, diet diversity & variety and diet sufficiency.
This finding suggests that informal
groups such as family members, friends, colleagues and mass media are important
sources to influence the practice of optimal dietary intake in students.
Previous studies using the TPB have suggested somewhat inconsistent results
regarding the influence of significant others, partly supporting the results of
the current study [19,20]. Previously, [21,22] argued that a potential way to
improve individual’s dietary intake was to intervene in the social norms that
govern eating behaviour. Improving the social norms surrounding optimal dietary
intake may stimulate healthy instead of unhealthy dietary intake of an
individual. Fostering strong combined relationships amongst significant other
is fundamental to support any individual practicing optimal dietary intake.
When social and environmental support systems are in place, making healthful
choices becomes possible and has an opportunity to improve dietary habits [23].
Influence
of Student’s Perceived Behavioural Control on Optimal Dietary Intake
A statistically significant
influence of indirect perceived behavioural control [β = 0.64, P <0.01, N =
230] and a statistically least significant direct perceived behavioural control
[β = 0.12, P &li;0.05, N = 230] were reported. Ajzen’s contended that the
direct link may only be apparent when perceived control closely parallels
actual control. We conjecture that perceived control did not parallel actual
control in this group of respondents, for whom the sense of dietary intake
control only exerted its effect more indirectly through intentions. The
indirect measure was promising because it showed that though students have
other obstacles to optimal dietary intake, they have confidence in their
ability to practice it. Previous research reported positive relationship
between indirect perceived behavioural control and intention [24]. It was
hypothesized that perceived dietary intake control would influence optimal
dietary intake as it would be similar to self- efficacy, since both are concerned
with perceived ability to perform a behaviour. When a student has higher sense
of self-efficacy regarding optimal dietary intake, they will react more
positively when problems arise and persist when confronted with problems.
Therefore, a higher perceived behavioural control score in the indirect measure
should be associated with lower problem severity perceptions in practice of
optimal dietary intake.
Increasingly, younger Kenyans
inclusive of university students have access to more education opportunities,
consequentially higher possibilities for nutrition knowledge and their dietary
intake habits. Based on the study analysis, student’s attitude, subjective
norm, and indirect perceived behavioural control had a statistically
significant influence on their intention of practicing optimal dietary intake.
However, the direct influence of perceived behavioural control on optimal
dietary intake illustrated a very minimal prediction (β = 0.12, P > 0.05, N
= 230). As the analytical results of [24] showed that although direct perceived
behavioural control is reasonably explained by belief control, it does not in
turn provide better prediction of intention over and above that provided by
indirect subjective norm, attitude, and perceived behavioural control. Furthermore,
[25] also claimed that the direct perceived behavioural control is less likely
to be related to intention. Given that the influence of student’s attitude,
subjective norm and perceived behavioural control statistically influenced
intention (β = 0.95, P < 0.001, N =230), this study established these
psychosocial factors practically influences optimal dietary intake of students.
This indicates that a unit change in student’s attitude, subjective norm and
perceived behavioural control was associated with a change of 0.68, 0.52, 0.64
units respectively, in intention. A variance of 74% was obtained for intention
predictors, whereas direct perceived behavioural control and intention
accounted for 68% of variance on optimal dietary intake. Thus, the aspect of
predictability of psychosocial factors is not just a mere postulation but a
logically proven detail.
Implications
for Practice and Research
Our data reveal that psychosocial
factors remain statistically significant in influencing optimal dietary intake
of university students. Since students desire to practice optimal dietary
intake but they encounter barriers that originate from their attitude, social
pressures from significant referents and their self-efficacy [confidence].
These attitudinal, normative, and control beliefs, which the study has
determined to be predictive, are optimal dietary intake barriers/facilitators
that limit students’ capability of practicing optimal dietary intake. Hence,
efforts should include further promotion and research into students’ perception
of the value of optimal dietary intake that affects their attitude. Significant
others should address the issue of social support and influence optimal dietary
intake intention. Discussing the students’ worries, providing education on the
anxiety response and offering help with structured problem solving and
sustainable techniques may help alleviate the students’ self-efficacy towards
optimal dietary intake, thus boosting their emotional support. To enhance
students’ selfefficacy, they need to be informed of the challenges that may
arise during practice of optimal dietary intake and how to overcome them.
Therefore, this research confirms that psychosocial factors, namely, students’
attitude, subjective norm, perceived behavioural control are important
predictors of optimal dietary intake and may also hinder the practice of
optimal dietary intake among young adults inclusive of university students.
Conclusion
Optimal dietary intake promoters,
practitioners and researchers should capitalize on understanding and motivating
young people including university students about these psychosocial factors
that determine intention of optimal dietary intake by using the generated
modified framework from Ajzen’s TPB. Since our findings support the use of the
TPB to predict the influence of students’ attitude, subjective norm/social
pressures and perceived behavioural control on optimal dietary intake
intention, it is significant for programs to incorporate strategies that target
individuals’ beliefs which in turn reveal what beliefs and factors need to be
addressed for optimal dietary intake to be practiced. Although dietary intake
of respondents in the 5 universities varied, they were only reported and
controlled during analysis but not established. The analysis of dietary intake
in each of the 5 universities could have been conducted by comparing model
fitness indices; however, sample size did not allow for smaller clustering of
respondents. This study recommends that educating university students about the
benefits of optimal dietary intake, identifying barriers to optimal dietary
intake, developing strategies to address the barriers and identifying the
significant referents may be important areas to target for
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