Centre for Physical Activity and Nutrition Research, School of Exercise and Nutrition Sciences, Deakin University, Australia
Abstract
Background
Snacking is likely to play an important role in the development of overweight and obesity, yet little is known about the contexts of snacking in adolescents or how snacking may influence other dietary habits, like meal skipping. This study examines the contexts in which adolescents snack and whether these contexts are associated with demographic characteristics of adolescents and with meal skipping.
Methods
A cross-sectional, self-reported online food habits survey was administered to 3,250 secondary students in years seven and nine. The students were drawn from 37 secondary schools in Victoria, Australia during 2004–2005. Frequencies of meal skipping, and snacking in eight contexts, were compared across gender, year level and region of residence. Logistic regressions were performed to examine associations between snacking contexts and meal skipping adjusting for gender and region.
Results
The most common contexts for snacking among adolescents were after school (4.6 times per week), while watching TV (3.5 times per week) and while hanging out with friends (2.4 times per week). Adolescents were least likely to snack all day long (0.8 times per week) or in the middle of the night (0.4 times per week). Snacking contexts were variously associated with gender, year level and region. In contrast, meal skipping was associated with gender and region of residence but not year level. Adolescents who reported more frequent snacking on the run, on the way to or from school, all day long, or in the middle of the night were more likely to skip meals.
Conclusion
These data suggest adolescents snack frequently, especially in their leisure time. In addition, adolescents who snack on the run, on the way to or from school, all day long or in the middle of the night are more likely to skip meals than are adolescents who don't snack at these times. Understanding the contexts in which adolescents snack, and their associations with skipping meals, may assist those involved in the promotion of healthy food habits among adolescents.
Background
The rapid increase over the past three decades in the prevalence of childhood obesity in developed countries across the world
The prevalence of snacking (defined as
Snacking is also commonly associated with undesirable health outcomes and dietary patterns. Since children and adolescents select snacks based on taste over nutrition, they more often choose salty, crunchy foods as snacks over healthier alternatives
The literature exploring associations between snacking behaviour and demographic characteristics in children and adolescents is relatively scarce and contradictory. For example, the few studies that have examined the association between gender and snacking have yielded mixed results, with more frequent snacking reported among boys than girls
Surprisingly little is known about the context of snacking in adolescents, or how snacking may influence other dietary habits, such as meal skipping. While previous research shows that snacking among children and adolescents occurs most often in the afternoon
The aim of the present study is to examine the contexts in which adolescents snack and to determine whether snacking contexts are associated with gender, year level, or region of residence. In addition, this study aims to examine whether snacking is associated with a higher frequency of meal skipping, and more specifically, which snacking contexts predict meal skipping.
Methods
Study procedure
For this study, we used cross-sectional data derived from the Youth Eating Patterns (YEP) survey, an online food habits survey conducted in secondary schools. The survey was administered during 2004 and 2005 and was approved by the Ethics committee of Deakin University and the Victorian Department of Education and Training and the Catholic Education Office. All co-educational state (government) and Catholic schools (including years 7 to 12), located in the Southern metropolitan region of Melbourne and the non-metropolitan region of Gippsland to the east of Melbourne, Australia, and with enrolments over 200, were invited to participate. Of the 70 schools (47 metropolitan and 23 non-metropolitan) that met these criteria, 37 schools (20 metropolitan and 17 non-metropolitan) agreed to participate in the study.
All students (
Teachers administered the online survey to students during a class when they had access to computers. Teachers instructed the students to type in the URL of the YEP survey, which was provided to teachers along with additional information covering answers to frequently asked questions and the procedure to re-commence the survey at a later time if students were unable to complete on the day. Further details of the sample and data collection procedures are described in a previous publication
The present analyses are based on a subset of 3,250 students who completed sections of the survey on snacking behaviour.
Measures
Prior to administration of the online survey, and as part of its development, the survey items were trialled among students from three classes in three separate schools (
Snacking
Snacks were defined as
Meal skipping
Meal skipping was assessed by asking adolescents how often over the past month they had: 'skipped breakfast', 'skipped lunch', and 'skipped dinner'. Possible responses were 'not in the last month', 'once-twice a month', 'once-twice a week', 'most days', or 'every day'.
Statistical analyses
The data were analysed using SPSS version 12.0. Descriptive statistics were used to describe the snacking and meal skipping habits of adolescents. Differences in snacking and meal skipping frequencies in relation to year level, sex and region of residence were analysed using the chi-square statistic and the categories responsible for significant χ2 values were identified by examining the standardized residuals
The mean number of times adolescents snacked per week was calculated by converting response categories to a weekly equivalent (e.g. once-twice a month = 0.05 times/week; once-twice a week = 1.5; most days = 5 times/week).
Logistic regression was used to examine whether eight different snacking contexts (predictor variables) were associated with skipping breakfast, lunch or dinner (outcome variables). Since snacking contexts were not mutually exclusive, adolescents could include the same snacking behaviour in more than one context (e.g. 'after school', 'while hanging out with friends' and 'while watching television'). Consequently, the logistic regression analyses were performed separately for each snacking context. Since our chi-square analyses showed that sex and region of residence were associated with meal skipping, all models adjusted for these factors. For each snacking context, adolescents were classified into one of four groups: 'non-snackers' (not snacked in the last month), 'low snackers' (snacked once-twice a month), 'medium snackers' (snacked once-twice a week) and 'high snackers' (snacked most days or every day). Adolescents who skipped breakfast, lunch or dinner most days or more were classified as 'meal skippers'. A
Results
Characteristics of the sample
The sociodemographic characteristics of the sample are presented in Table
Demographic characteristics
%
Sex
(
Male
47
Female
53
Year level
(
Year 7 (12–13 years)
62
Year 9 (14–15 years)
38
Region of Victoria
(
Metropolitan
67
Non-metropolitan
33
Snacking
The frequency of snacking among adolescents across eight snacking contexts is shown in Table
Frequency of snacking among adolescents in eight snacking contexts according to year level, gender and region
Snacking context
M (± SD) snacking/weeka
Total %
Year level %
Gender %
Region %
7
9
Male
Female
Metro
Non-Metro
After school
4.6 (± 2.4)
**
4
4
3
4
3
4
3
7
8
7
8
7
8
5
14
14
14
14
14
15
13
41
39
43
39
43
40
42
34
35
33
35
33
33
37
While watching TV
3.5 (± 2.5)
**
7
8
6
9
6
7
9
12
12
11
12
12
12
12
26
25
28
24
27
24
29
39
39
39
38
39
40
35
16
16
16
17
15
17
15
While hanging out with friends
2.4 (± 2.5)
**
**
14
16
11
17
12
15
13
25
24
27
24
27
25
25
24
22
27
24
24
23
26
27
27
26
25
27
27
25
10
11
9
10
10
10
11
While doing homework or working
1.8 (± 2.3)
**
*
29
30
28
36
24
30
28
20
19
21
19
21
19
21
23
23
24
20
26
22
26
22
22
21
19
24
23
19
6
6
6
6
5
6
6
On the run
1.3 (± 2.0)
**
28
30
25
31
25
29
26
30
30
31
28
32
30
31
24
23
26
22
26
23
26
14
14
15
14
14
14
14
4
4
4
5
3
4
4
On the way to or from school
1.0 (± 2.0)
*
57
56
59
56
57
57
56
17
17
17
17
17
17
17
12
13
11
11
13
12
13
10
10
8
10
10
10
9
4
4
5
6
3
4
5
All day long
0.8 (± 1.8)
**
63
67
56
63
63
62
65
16
14
20
15
16
16
16
10
9
12
10
11
11
10
8
7
8
8
7
8
6
3
3
4
4
3
3
3
In middle of night
0.4 (± 1.4)
**
**
80
81
78
75
84
77
85
9
9
10
10
9
11
6
5
4
5
6
3
5
4
4
4
4
5
3
4
3
2
2
3
4
1
3
2
Snacks are defined as foods and/or drinks that are consumed outside the main meals of breakfast, lunch and dinner.
a Mean (± SD) times per week adolescents (
* p ≤ 0.01, ** p ≤ 0.001. Pearson's chi square test of significance.
The contexts in which adolescents snacked were associated with year level, sex and region of residence (Table
Several snacking contexts were also associated with gender (Table
Snacking contexts were also associated with region of residence (Table
Meal skipping
On a daily basis, more adolescents skipped breakfast (20%) than skipped lunch (12%) or dinner (2%) (Table
Frequency of meal skipping among adolescents according to year level, sex and region
Meal
Total
Year level
Gender
Region
7
9
Male
Female
Metro
Non-Metro
Breakfast
**
**
20
19
21
16
23
21
17
80
81
79
84
77
79
83
Lunch
*
12
11
12
10
13
12
10
88
89
88
90
87
88
90
Dinner
2
2
2
2
2
3
1
98
98
98
98
98
97
99
Values are presented as %
Skips = skips a meal most days or every day
Eats = skips a meal once-twice a week or less
* p ≤ 0.01, ** p ≤ 0.001. Pearson's chi square test of significance.
Snacking and meal skipping
Logistic regression analyses were performed to predict the odds of adolescents skipping meals when snacking in different contexts (Table
Adjusted odds ratios (OR) and 95% confidence intervals (CI) for snacking in eight snacking contexts and the likelihood of skipping meals among adolescents
Breakfast
Lunch
Dinner
Snacking context
OR
95% CI
OR
95% CI
OR
95% CI
After school
1.00
1.00
1.00
0.69
0.41–1.16
0.87
0.44–1.70
1.01
0.37–2.77
0.78
0.49–1.24
0.77
0.41–1.43
0.48
0.18–1.34
0.66
0.43–1.01
0.94
0.54–1.65
0.36
0.15–0.86
While watching TV
1.00
1.00
1.00
0.68
0.44–1.05
0.80
0.47–1.35
0.52
0.20–1.36
0.85
0.59–1.24
0.87
0.55–1.38
0.31
0.12–0.77
*
1.25
0.88–1.77
1.14
0.74–1.74
0.64
0.31–1.32
While hanging out with friends
1.00
1.00
1.00
0.96
0.70–1.30
0.36
0.59–1.21
0.49
0.23–1.04
1.24
0.92–1.68
0.94
0.69–1.41
0.48
0.22–1.04
1.38
1.04–1.83
0.69
0.77–1.49
0.84
0.45–1.57
While doing homework or working
1.00
1.00
1.00
0.50–2.25
0.72
0.55–0.95
0.69
0.49–0.98
1.06
0.44–1.97
1.01
0.79–1.29
0.96
0.71–1.30
0.93
1.08–3.61
1.33
1.06–1.66
*
1.39
1.06–1.82
1.97
0.58–1.48
On the run
1.00
1.00