¹ Health Research Institute, Diabetes Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
² Department of Nutrition, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
³ Department of Health Information Technology, School of Paramedical Sciences, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
⁴ Nutrition and Metabolic Diseases Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
⁵ Nutrition Department, School of Paramedicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
⁶ Nutrition and Food Security Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.

ARTICLE INFO		ABSTRACT
ORIGINAL ARTICLE		Background: The important risk factors in obesity are related to unhealthy nutritional habits. The aim of this study was to estimate and compare the macro- and micro-nutrients’ intake in breakfast and midmorning snacks. Methods: This cross-sectional study was conducted among 569 students (12-16 years) by the multistage cluster sampling method. The demographic data were gathered by interview. Anthropometric data and breakfast habits (breakfast frequency and time as well as nutrients’ intake at breakfast or snacks) were measured using standardized instruments by asking some questions. Results: The results showed that the high prevalence of irregular breakfast eating (IRBE) and overweight or obesity. No significant difference was found between breakfast frequency and time according to the students’ gender or body mass index (BMI). The mean BMI had a significant increase in females; whereas, the percentage of energy from breakfast (EB%), snack (ES%), or both breakfast and snacks (EBS%) were shown no significant difference between genders. A significant increase was found in EB%, EB%, and EBS%; whereas, the daily energy intake (DEI) was lower in normal-weight students. However, other nutrients at breakfast or snacks had no significant difference. The level of higher DEI was reported in IRBE adolescents. Conclusions: An inappropriate breakfast habit can cause irreparable consequences in adolescents. Although breakfast plays an undeniable role, other factors are also effective in one’s health. Further studies are required for more comprehensive results. Keywords: Breakfast; Midmorning snacks; Nutrients; Adolescents; Overweight; Obesity
Article history: Received:2 Feb 2020 Revised: 21 Jun 2020 Accepted: 12 May 2020
*Corresponding author: azhdari_mar@yahoo.com PhD candidate (Nutritional Sciences), Nutrition and Metabolic Diseases Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.   Postal code: 61357-15794 Tel: +98 9131571909

Introduction

The prevalence of overweight and obesity is gradually increasing among adolescents around the world (Gortmaker et al., 2011). The overweight or obesity rate was reported as 18% in 2016 based on the World Health Organization (WHO) report. The increasing rate was similar in males and females (World Health Organization, 2018). The prevalence of obesity and overweight was reported relatively remarkable among Iranian adolescents and children (Ahadi et al., 2015, Maddah, 2007);(Rashidi et al., 2007).
Given that childhood obesity is related to hypertension, (Malhotra and Nistane, 2016), insulin resistance, (Caprio et al., 2017), and cardiovascular risk factor (Raj and Kumar, 2010), it is considered as one of the serious concerns (Malhotra and Nistane, 2016). Some factors associated with overweight and obesity include lifestyle habits (low physical activity, and food intake behaviors (Ahadi et al., 2015) such as increased fast food consumption and breakfast skipping) (Alimoradi et al., 2017).
Breakfast skipping is common among children and adolescents and its prevalence is increasing with age (Rampersaud et al., 2005). It is associated with inappropriate levels of blood glucose, lipids (such as triglycerides and very-low-density lipoprotein cholesterol) (Kesztyüs et al., 2017), unhealthy lifestyle (Kang and Park, 2016, Monzani et al., 2019), lower diet quality, increased risk for chronic diseases, and lower overall health. However, selecting every kind of food for breakfast cannot provide energy and essential nutrients; so, the quality of breakfast is important (O'Neil and others 2014). Breakfast provides about 15-25 % of the daily energy needs of children (Gibney et al., 2018, O'Neil et al., 2014). Although snacks can provide some key nutrients, the frequency and quality of the consumed foods in snacks are important. Furthermore, we are faced with paucity of information regarding the effect of snacks on weight status in young people (Larson and Story, 2013).
Given the importance of this issue and lack
of related studies, this research was aimed to estimate and compare breakfast habits (the
macro- and micro-nutrients intake of breakfast
and midmorning snacks, as well as breakfast frequency and time) among high school students in Yazd City, Iran.
Materials & Methods
Study design and sample gathering:            This cross-sectional study was conducted among 12-16 years old high school students of Yazd, located in the center of Iran. A random multistage cluster sampling method was performed to select the students. The eligibility criteria for the participating students included submitting written consent (the students and their parents) to cooperate in the study; living in Yazd for more than six months; having no diseases such as Hormonal impairment (thyroid, insulin, sex hormone and etc.), cardiovascular disorders, digestive diseases, pulmonary disease, kidney disease, megalomaniac, anxiety, and depression; having no history of hospitalization in the last 6 months for any reason (e.g., fractures, injuries, etc.); not being exposed to unpleasant events the last year (death of parents, parental divorce, death of family members); living with one of the parents or relatives for any reason; and using no drugs including narcotic and psychotropic drugs. All information was recorded by the trained research assistants.
Demographic characteristics: The demographic data (gender, age, household size, and grade) were gathered by interviews and then the collected data were checked based on the students' records.
Anthropometric data: Anthropometric data,
such as weight, height, body mass index (BMI) and waist circumstance (WC)) were measured using standardized instruments. The measurements of weight and height were conducted by a pre-calibrated electronic scale (Seca, Germany) to the nearest 0.1 kg and a stadiometer to the nearest
0.1 cm on a scale placed on flat ground. The participants’ BMI was calculated by dividing weight in kilogram by height squared in meter. Moreover, BMI for age was calculated by z-score (-2 to +2 in increments of two-thirds of a z score) (Cole, 1994). The calculated BMI z-scores were categorized into three groups; thin (BMI ≤-2SD), normal  (BMI between 1SD to -2SD), and overweight or obesity (BMI ≥1SD) (Onis et al., 2007). The WHO website has provided the BMI z-score tables (World Health Organization, 2016). A non-elastic strip was used to measure WC with a precision of 0.01 cm (Knowles et al., 2011).
Breakfast habits: Breakfast habits (breakfast timing and frequency, midmorning snacks intake) were collected by asking some questions. For example,
1) ‘‘How many times per week do you consume breakfast?” Response categories: irregular breakfast eating (IRBE) (0-4 times/week), regular breakfast eating (RBE) (5-7 times/week) (Hassan et al., 2018); 2) what time do you have breakfast during the week? Response categories: a) before 9:30 (H: min), b) after 9:30 (H: min) (Grieger and Cobiac, 2012); 3) “Do you have a midmorning snacks daily?” Yes or No. 4) Where do you get your breakfast? Response categories: a) home, b) out of home (buying food from the school’s buffet/at shops away from school or eating at a restaurant) (Maddah et al., 2009).
Calculation of total energy expenditure and Basal metabolic rate: The total energy expenditure (TEE) was calculated by the following formula (James and Schofield, 1990):
TEE= Basal metabolic rate (BMR) × physical activity level (PAL)  
BMR for boys: 17.5 × weight + 651
 BMR for girls: 12.2 × weight + 746
Nutrient contributions: Breakfast and morning snacks intake were obtained from a 7-day food record (24-hour dietary recalls for 7 consecutive days). The research assistants were required to train the students on how to complete food records. The students were required to deliver the completed forms daily. To this end, a research assistant was at the school every morning for 2 hours (to check the students' forms). Nutritionist 4 software (version I) was run to estimate the daily energy intake (DEI) (Kcal), the amount of macro- and micro-nutrients of breakfast and morning snacks: the energy intake at breakfast (E_B), the energy intake at midmorning snacks (E_S), or overall breakfast and midmorning snacks (E_BS) (Kcal), protein (g), total carbohydrate (g), total fat (g), saturated fat (g), total fiber (g), fat-soluble vitamins (A, D, K (µg), and E (mg)), water-soluble vitamins B complex and C (mg), zinc (mg), iron (mg), calcium (mg), sodium (mg), and caffeine (mg). Also, the proportion of energy intake at breakfast, midmorning snacks or both of them were calculated by the following formula.
E_B % or E_S % = the ratio of breakfast or midmorning snacks to overall energy intake
E_B % or E_S % = (E_B or E_S/ DEI) × 100
E_BS % = the ratio of breakfast and midmorning snacks to overall energy intake
E_BS % = (E_BS/ DEI) × 100
Data analysis: The mean ± standard deviation (SD) and percentages were used to describe the variables. The normality distribution was tested by the Kolmogorov-Smirnoff test to distinguish the parametric or non-parametric test.  Independent t-test was used to compare the continuous variables. Analysis of covariance (ANCOVA) was applied to compare the nutrients intake between genders. Moreover, the analysis was adjusted for the confounding variables (TEE and DEI). All data were analyzed by SPSS version 22 (SPSS, Inc, Chicago, Illinois, USA). Statistical tests were analyzed at the significant level of < 0.05.
Ethics considerations: The students and their parents filled out written consent forms to participate in this study. The study protocol was approved by the Research Ethical Committee of Ahvaz Jundishapur University of Medical Sciences (IR.AJUMS.REC.1396.1087).
Results
Among 569 adolescents, 52.2% and 47.8 % were boys and girls, respectively. The mean of students’ age, BMI, and WC were 14.24 ± 0.88 years, 21.66 ± 4.74 (kg/m²), and 72.98 ±11.15 (cm), respectively. The baseline descriptive characteristics of the students are illustrated in Table 1. The prevalence of IRBE was 61.9% among the students. The midmorning snacks intake was reported among 85.6% of adolescents. The breakfast of 96.3% of the students was prepared from home.
The distribution of the macro- and micro-nutrients intake at breakfast and midmorning snacks is shown in Table 2. Significantly, the students showed a higher intake for energy, total carbohydrate, total fat (P < 0.01), energy, saturated fat, and zinc (P < 0.05) in midmorning snacks. However, the mean of protein, caffeine, iron, and calcium were significantly higher at breakfast (P < 0.01). The intake of total fiber, sodium, some of fat-soluble vitamins (A, D, E, K), and water-soluble vitamins (B complex, C)
did not reveal a significant difference between midmorning snacks and breakfast (P > 0.05). 
The comparison of breakfast frequency and time (mean ± SD) did not show a statically significant difference based on gender, (3 ± 2.85 vs. 2.6 ± 2.5; 09:10 ± 00:43 vs. 09:02 ± 01:02 (boy vs. girl students, P > 0.05), respectively. Adjusted BMI (mean ± SD) for age had a significant increase in females (20.434 ± 4.67 (male) vs. 23.030 ± 4.8 (female), P < 0. 01).
The TEE and DEI (mean ± SD) were significantly higher among the male students (2730.39 ± 411.46 vs. 2433.15 ± 326.79, 2593.04 ± 496.88 vs. 2311.15 ± 409.38, P < 0.01); but the ratio of DEI to TEE did not show a significant difference between genders (0.95 ± 0.13 (male) vs. 0.95 ± 0.10 (female), P > 0.05).
 Significantly, E_B% (adjusted mean ± SD) was higher in males (P < 0.05); but no significant difference (adjusted mean ± SD) was observed regarding E_S%, E_BS %, and E_BS between both genders (P > 0.05) (data were not listed in the tables). The comparison of the macro- and micro-nutrients intake at breakfast and midmorning snacks between genders is presented in Table 3.
At breakfast, adjusted mean total carbohydrate, total fat, saturated fat, fat-soluble vitamins, vitamin B complex, vitamin C, and caffeine were significantly higher among the male students (P < 0.05). Given the midmorning snacks, boys consumed significantly higher adjusted mean total carbohydrate, protein, saturated fat, vitamin C, zinc, calcium, and iron than girls. However, the other nutrients did not show a significant difference between genders.
Considering the BMI categories (normal weight group, overweight or obesity groups), no significant difference was observed for mean ± SD of the breakfast time and frequency (9:05 ± 00:59 vs. 9:06 ± 00:43 and 2.63 ± 2.5 vs. 3 ± 2.85, P > 0.05). Moreover, no significant difference was observed between E_BS (Kcal) and the normal weight and overweight or obesity adolescents (P > 0.05), but E_BS %, E_B %, and E_S % were greater in the normal weight students compared to the overweight or obesity group (P < 0.05). A significant increase was found in DEI among the overweight or obese adolescents compared to the normal-weight adolescents (2301.69 ± 386.00 vs. 2778.57 ± 446.03, P < 0.01). Data are not shown in the table.
According to Table 1, only 3.5% of the students were thin; so, distribution of the macro- and micro-nutrients intake was compared between the two study groups (the normal weight group and overweight or obesity group). Table 4 illustrates comparison of the nutrients’ intake at breakfast and midmorning snacks between normal weight and overweight or obesity students. The comparison of nutrients intake did not represent a significant difference between the normal-weight group and overweight or obesity group at breakfast or midmorning snacks (P > 0.05).
According to the breakfast frequency, mean of BMI was not significantly different between the IRBE and the RBE groups (21.57 ± 4.82 VS. 21.81 ± 4.65; P > 0.05). However, DEI was significantly higher in the IRBE group than the RBE group (2535.37 ± 27.75, 2359.95 ± 27.74; P < 0.01).

 

Table 1. The baseline descriptive characteristics of the students
Variables	N	%
Gender    Boy    Girl	297 272	52.2 47.8
Grade    Seventh    Eighth    Ninth	143 181 245	25.1 31.8 43.1
Weight status     Thin    Normal    Overweight or obesity	30 306 203	5.5 56.7 37.6
Household size    Less than 4    More than 4	290 230	55.8 44.2
Breakfast frequency    Irregular breakfast eating (0-4 times/wk)    Regular breakfast eating (5-7 times/wk)	352  217	61.9 38.1
Breakfast time     Before 9:30 AM    After 9:30 AM	279 29	90.6 9.4
Midmorning snacks    No   Yes	82 487	14.4 85.6
The place of breakfast preparation    Home      Out of home	335 13	96.3 3.7

 

Table 2. Comparison of mean (±SD) of the macro- and micro-nutrients’ intake between breakfast and midmorning snacks
Nutrients	Breakfast (N= 340)	Midmorning snacks (N= 487)	P-valuea
Energy (Kcal)	355.68 ±140.21	549.80 ± 38.52	0.002
Energy (%)b	14.50 ± 8.67	20.05 ± 11.10	<0.001
Total carbohydrate (g)	43.39 ± 24.57	61.34 ± 5.39	0.005
Total Fiber (g)	6.67 ± 4.79	5.36 ± 0.44	0.3
Protein (g)	87.21 ± 37.67	7.55 ± 0.91	0.003
Total Fat (g)	16.00 ± 3.86	32.40 ± 1.90	0.001
Saturated Fat (g)	4.39 ± 1.32	10.31 ± 0.73	0.01
Vitamin A (µg)	54.06 ±19.36	75.75  ± 23.48	0.004
Vitamin E (mg)	3.29 ±1.09	12.79 ± 0.51	0.5
Vitamin D (µg)	0.32 ± 0.12	0	-
Vitamin K (µg)	9.08 ± 2.00	25.54 ± 1.71	0.05
Vitamin C (mg)	6.10 ± 0.92	47.37 ± 10.70	0.2
Vitamin B complex (mg)	6.36 ± 3.37	5.37 ± 0.28	0.4
Zinc (mg)	1.96 ± 0.96	15.54 ± 4.92	0.02
Iron (mg)	2.73 ± 1.71	1.71 ± 0.16	0.008
Calcium (mg)	195.19 ± 50.39	46.48 ±12.21	<0.001
Sodium (mg)	510.87 ±287.35	555.47 ± 33.36	0.2
Caffeine (mg)	1.54 ±4.65	0.56 ± 0.61	0.001
a: Student t-test; b:Ratio of intake of energy from breakfast and midmorning snack to total energy intake.

 

Table 3. Comparison of mean (±SD) of the macro- and micro-nutrients intake at breakfast or midmorning snacks between genders
Nutrients	Unadjusted			Adjusted
	Male	Female	P_valuea	Male	Female	P_valueb
Breakfast
Energy (kcal)	372.4 ± 135.1	335.9 ± 143.9	0.01	374.6 ± 134.2	330.7 ± 144.8	0.01
Total carbohydrate (g)	45.69 ± 23.67	40.69 ± 25.41	0.06	46.11 ± 23.74	39.86 ± 25.6	0.04
Total Fiber (g)	6.99 ± 4.74	6.33 ± 4.84	0.2	7.07 ± 4.16	6.16 ± 4.99	0.1
Protein (g)	90.18 ± 35.55	84.00 ± 39.9	0.1	90.64 ± 36.76	82.85 ± 39.46	0.1
Total Fat (g)	16.76 ± 3.9	15.10 ± 3.62	<0.001	16.77 ± 3.66	14.95 ± 3.87	<0.001
Saturated Fat (g)	4.64 ± 1.37	4.11 ± 1.22	<0.001	4.46 ± 1.22	4.05 ± 1.37	0.001
Vitamin A(µg)	1549.8 ± 321.4	1430.1 ± 255.8	<0.001	57.52 ± 18.58	49.36 ± 19.98	0.003
Vitamin E (mg)	3.52 ± 1.17	3.03 ± 1.0	<0.001	2.11 ± 0.54	1.81 ± 0.62	<0.001
Vitamin D (µg)	.34 ± 0.12	0.30 ± 0.13	0.01	0.34 ± 0.13	0.3 ± 0.12	0.02
Vitamin K (µg)	9.4 ± 2.14	8.62 ± 1.7	<0.001	9.45 ± 1.89	8.56 ± 1.99	<0.001
Vitamin C (mg)	6.30 ± 1.03	5.85 ± 0.69	<0.001	6.27 ± 0.81	5.84 ± 0.87	<0.001
Vitamin B complex	6.65 ± 3.25	6.02 ± 3.48	0.08	6.68 ± 3.39	6.01 ± 3.37	0.08
Zinc (mg)	2.04 ± 0.92	1.86 ± 0.99	0.09	2.05 ± 0.81	1.86 ± 0.99	0.08
Iron (mg)	2.88 ± 1.65	2.56 ± 1.77	0.09	2.90 ± 1.76	2.51 ± 1.74	0.07
Calcium (mg)	198.7 ± 48.3	190.9 ± 52.5	0.1	200.2 ± 48.8	188.8 ± 52.4	0.1
Sodium (mg)	529.1 ± 277.5	489.3 ± 297.9	0.2	535.2 ± 279.4	480.5 ± 301.0	0.1
Caffeine  (mg)	2.25 ± 6.15	0.70 ± 1.16	0.001	2.13 ± 4.47	0.67 ±  4.74	0.007
Midmorning Snacks
Energy (Kcal)	554.5 ± 39.72	545.0 ± 36.76	0.006	554.2 ± 31.19	544.3 ± 40.61	0.01
Total carbohydrate (g)	62.30 ± 5.72	60.39 ± 4.87	<0.001	62.18 ± 5.14	60.32 ± 5.62	<0.001
Total Fiber (g)	5.40 ± 0.52	5.32 ± 0.34	.03	5.40 ± 0.46	5.32 ± 0.46	0.05
Protein (g)	7.72 ± 1.0	7.38 ± 0.78	<0.001	7.70 ± 0.77	7.35 ± 0.93	<0.001
Total Fat (g)	32.47 ± 1.89	32.34 ± 1.91	0.4	32.49 ± 1.74	32.30 ± 2.03	0.4
Saturated Fat (g)	10.30 ± 0.72	10.32 ± 0.74	0.7	10.32 ± 0.62	10.31 ± 0.78	0.8
Vitamin A (µg)	76.15 ± 23.38	75.35 ± 23.43	0.1	75.82 ± 21.86	75.81 ± 24.99	0.3
Vitamin E (mg)	12.77  ± 0.51	12.82 ± 0.52	0.2	4.62 ± 0.15	4.63 ± 0.15	0.2
Vitamin D (µg)	0	0	-	0	0	-
Vitamin K (µg)	25.52 ± 1.71	25.55 ± 1.56	0.8	25.54 ± 0.15	25.56 ± 0.11	0.8
Vitamin C (mg)	49.31 ± 12.77	45.43 ± 7.91	<0.001	48.94 ± 15.43	45.54 ± 14.52	0.001
Vitamin B complex	5.40 ± 0.31	5.35± 0.26	.07	5.4 ± 15.43	5.36 ± 0.15	0.1
Zinc (mg)	16.49 ± 5.58	14.59 ± 3.95	<0.001	16.34 ± 72.17	14.49 ± 5.15	0.03
Iron (mg)	1.74 ± 0.17	1.68 ± 0.13	<0.001	1.73 ± 0.15	1.68 ± 0.15	<0.001
Calcium (mg)	48.20 ± 13.66	44.76 ± 10.31	.002	48.18 ± 11.69	44.42 ± 12.8	.02
Sodium (mg)	557.9± 35.4	553.0 ± 30.9	0.1	557.9 ± 34.7	553.0 ± 34.8	0.1
Caffeine (mg)	0.58 ± 0.64	0.54 ± 0.59	0.5	0.57 ± 0.62	0.553 ± 0.62	0.7
a Statistical analysis was performed by an independent t-test; b Statistical analysis was performed using ANCOVA, Adjusted for TEE (2590.86) and daily energy intake (2395.90) (kcal/day)

 

 

Table 4. Comparison of  mean (±SD) of the macro- and micro-nutrient intake at breakfast or midmorning snacks between normal weight and overweight or obesity group
Midmorning snacks			Breakfast			Nutrients
P_valuea	Overweight  or obesity a	Normal  weight a	P_valuea	Overweight  or obesity a	Normal  weight a
0.7	550.2 ± 40.1	548.8 ± 37.7	0.3	348.4 ± 150.2	363.4 ± 133.0	Energy (Kcal)
0.5	61.49 ± 5.82	61.15 ± 5.16	0.3	42.08 ± 26.61	44.86 ± 23.16	Total carbohydrate(g)
0.2	5.40 ± 0.55	5.34 ± 0.37	0.3	6.4 ± 5.3	6.9 ± 4.4	Total Fiber (g)
0.8	7.53 ± 0.92	7.52 ± 0.87	0.3	85.09 ± 39.89	89.41 ± 35.96	Protein (g)
0.9	32.39 ± 1.92	32.40 ± 1.92	0.6	15.89 ± 3.88	16.09 ± 3.87	Total Fat (g)
0.5	10.29 ± 0.71	10.33 ± 0.76	0.4	4.31 ± 1.34	4.43 ± 1.28	Saturated Fat (g)
0.4	76.13 ± 24.92	75.24 ± 22.36	0.1	52.99 ± 16.31	54.35 ± 21.4	Vitamin A (µg)
0.3	12.83 ± 0.52	12.78 ± 0.52	0.5	3.34 ± 0.93	3.26 ± 1.18	Vitamin E (mg)
-	0	0	0.7	0.32 ± 0.13	0.32 ± .12	Vitamin D (µg)
0.4	25.64 ± 1.77	25.51 ± 1.73	0.6	9.04 ± 1.79	9.14 ± 2.22	Vitamin K (µg)
0.1	48.31 ± 12.87	46.73 ± 9.55	0.4	6.04 ± 0.76	6.11 ± 1.00	Vitamin C (mg)
0.3	5.39 ± 0.31	5.36 ± 0.27	0.7	6.33 ± 3.54	6.45 ± 3.25	Vitamin B complex
0.8	15.45 ± 4.80	15.36 ± 4.67	0.4	1.91 ± 1.03	2.01 ± .91	Zinc (mg)
0.7	1.71 ± 0.16	1.70 ± 0.15	0.3	2.65 ± 1.86	2.82 ± 1.60	Iron (mg)
0.9	46.1 ± 12.7	46.2 ± 11.4	0.2	191.8 ± 53.6	198.6 ± 47.8	Calcium (mg)
0.6	555.8 ± 33.9	554.5 ± 32.9	0.3	495.4 ± 310.6	528.4 ± 269.2	Sodium (mg)
0.1	0.51 ± 0.59	0.60 ± 0.64	0.5	1.64 ± 6.36	1.35 ± 2.97	Caffeine (mg)
a: Student t-test

 

Discussion
The main findings showed the high prevalence of abnormal weight and IRBE, which is in agreement with the previous studies (Gortmaker et al., 2011, Saikia et al., 2016, Yang et al., 2006).The E_BS%, E_B%, and E_S % were higher in normal-weight students; whereas, the DEI was lower in normal-weight adolescents. Contrary to the study by Schusdziarra et al., increasing breakfast energy was associated with greater overall intake in normal-weight (Schusdziarra et al., 2011). It seems that a healthy breakfast plays an important role to improve the daily energy balance and overall health (Affinita et al., 2013, Ferrer-Cascales et al., 2018). No significant difference was found between the two genders and the students’ weight status with regard to the breakfast frequency and time. In agreement with the present findings, no relationship was reported between the prevalence of IRBE and weight status (Hassan et al., 2018, Rodrigues et al., 2016). However, some studies reported a higher prevalence of the overweight or obesity in breakfast skippers or IRBE (Boričić et al., 2014, O'Neil et al., 2014, Yang et al., 2006). No significant discrepancy was observed in the breakfast time among students, which can be justified by the fact that the data were collected in the second educational semester. Despite a significantly higher BMI in females, no significant difference was found E_B%, E_BS %, and E_BS between the genders. It seems that other factors, such as genetics, socioeconomic status (SES), level of physical activity, using computer, sleep duration, breastfeeding duration, and levels of parental education are associated with overweight and obesity prevalence in adolescents (Abiri et al., 2019, Narciso et al., 2019). Furthermore, higher daily energy intake was observed in IRBE adolescents, which is supported by  the study conducted by Pereira et al. (Pereira et al., 2018).
Based on the results, adolescents consumed more nutritious breakfast than midmorning snacks; however, E_S and E_S % were greater than E_B and E_B %, respectively. Some studies illustrated that the quality and quantity of the breakfast had an important role in daily energy intake (Kang and Park, 2016, Schusdziarra et al., 2011).
Some health-related macro- and micro-nutrients at breakfast or midmorning snacks were better in male adolescents than females. This result was in disagreement with the study by Monteagudo et al. They reported that breakfast quality index (BQI) scores were lower among boys in all age groups containing children and adolescents. The lowest BQI scores were observed in boys aged 14-17 years (Monteagudo et al., 2013).
The present study also had some limitations. The results of a cross-sectional study should be interpreted with caution. The results can be biased due to self-reporting method of data collection. Some confounding factors existed that were not measured. Finally, we did not consider other factors such as physical activity, quality of sleep, time of dinner, quality of dinner (Karatzi et al., 2017, Kesztyüs et al., 2017), and family meals (Rasmussen et al., 2006, Utter et al., 2008). The strengths of this study include its large sample size and simultaneous assessment of the breakfast and midmorning snacks by a 7-day food record.
Conclusions
The prevalence of overweight or obesity and IRBE were relatively high in high school students. However, breakfast frequency and time were not significantly different between male and female participants as well as the participants’ BMI. According to BMI, no significant increase was found for macro- and micro-nutrients except for the percentage of energy from breakfast, midmorning snack, and both of breakfast and midmorning snacks. The IRBE adolescents consumed higher daily energy intake.
An inappropriate breakfast habit (IRBE, high or low calories, and/or an insufficient variety of nutrients) can cause irreparable consequences in this age group. Although breakfast frequency and composition are very important among adolescents, other factors such as dinner quality, healthy back-to-school breakfast, physical activity, and SES are also effective. Given the importance of a healthy diet pattern in adolescents and determination of effective factors in overweight and obese adolescents, further related studies are required in this area.
Conflict of interests
The authors declare that they have no conflict of interest.
Acknowledgments
We are grateful for the cooperation of Yazd province's Education and Training Administration, the study schools, and students who participated in this research.
Authors’ contributions
Mozaffari-khosravi H, Karandish M and Azhdari M designed the research; Shams-Rad S, Tabatabaie M, Mirzavandy F, and Babaie S were responsible for the data collection; Azhdari M and Hadianfard AM analyzed the data; Azhdari M and Amiri R were involved in drafting the paper, Mozaffari-khosravi H and Karandish had primary responsibility for the final content. All authors read and approved the final paper.
 
Reference

Abiri B, Sarbakhsh P & Vafa M 2019. Prevalence of overweight, obesity, and associated risk factors in healthy female adolescents in Tehran, Iran. Central Asian Journal of Global Health. 8 (1).
Affinita A, et al. 2013. Breakfast: a multidisciplinary approach. Italian Journal of Pediatrics. 39 (1): 44.
Ahadi Z, et al. 2015. Association between breakfast intake with anthropometric measurements, blood pressure and food consumption behaviors among Iranian children and adolescents: the CASPIAN-IV study. Public Health. 129 (6): 740-747.
Alimoradi F, Jandaghi P, Khodabakhshi A, Javadi M & Moghadam SAHZ 2017. Breakfast and fast food eating behavior in relation to socio-demographic differences among school adolescents in Sanandaj Province, Iran. Electronic Physician. 9 (6): 4510.
Boričić K, Simić S, Vasiljević N & Marinković J 2014. Risk Factors Associated with Overweight among Adolescents in Serbia. Slovenian Journal of Public Health. 53 (4): 283.
Caprio S, Perry R & Kursawe R 2017. Adolescent obesity and insulin resistance: roles of ectopic fat accumulation and adipose inflammation. Gastroenterology. 152 (7): 1638-1646.
Cole T 1994. Do growth chart centiles need a face lift? British Medical Journal. 308 (6929): 641-642.
Ferrer-Cascales R, et al. 2018. Eat or skip breakfast? The important role of breakfast quality for health-related quality of life, stress and depression in Spanish adolescents. International Jjournal of Environmental Research and Public Health. 15 (8): 1781.
Gibney MJ, et al. 2018. Towards an evidence-based recommendation for a balanced
breakfast-a proposal from the international breakfast research initiative. Nutrients. 10 (10): 1540.
Gortmaker SL, et al. 2011. Changing the future of obesity: science, policy, and action. The Lancet. 378 (9793): 838-847.
Grieger J & Cobiac L 2012. Comparison of dietary intakes according to breakfast choice in Australian boys. European Journal of Clinical Nutrition. 66 (6): 667-672.
Hassan BK, Cunha DB, da Veiga GV, Pereira RA & Sichieri R 2018. Changes in breakfast frequency and composition during adolescence: The Adolescent Nutritional Assessment Longitudinal Study, a cohort from Brazil. PloS one. 13 (7): e0200587.
James WPT & Schofield EC 1990. Human energy requirements. A manual for planners and nutritionists. Oxford University Press.
Kang YW & Park J-H 2016. Does Skipping Breakfast and Being Overweight Influence Academic Achievement Among Korean Adolescents? Osong Public Health and Research Perspectives. 7 (4): 220-227.
Karatzi K, et al. 2017. Late-night overeating is associated with smaller breakfast, breakfast skipping, and obesity in children: The Healthy Growth Study. Nutrition. 33: 141-144.
Kesztyüs D, Traub M, Lauer R, Kesztyüs T & Steinacker JM 2017. Skipping breakfast is detrimental for primary school children: cross-sectional analysis of determinants for targeted prevention. BMC Public Health. 17 (1): 258.
Knowles K, et al. 2011. Waist Circumference, Body Mass Index, and Other Measures of Adiposity in Predicting Cardiovascular Disease Risk Factors among Peruvian Adults. International journal of hypertension. 2011: 931402.
Larson N & Story M 2013. A review of snacking patterns among children and adolescents: what are the implications of snacking for weight status? Childhood Obesity. 9 (2): 104-115.
Maddah M 2007. Overweight and obesity among Iranian female adolescents in Rasht: more overweight in the lower social group. Public Health Nutrition. 10 (5): 450-453.
Maddah M, Rashidi A, Mohammadpour B, Vafa R & Karandish M 2009. In-school snacking, breakfast consumption, and sleeping patterns of normal and overweight Iranian high school girls: a study in urban and rural areas in Guilan, Iran. Journal of Nutrition Education and Behavior. 41 (1): 27-31.
Malhotra K & Nistane R 2016. Study of obesity and hypertension in adolescents and their relationships with anthropometric indices. International Journal of Contemporary Pediatrics. 3: 1014-1021.
Monteagudo C, et al. 2013. Proposal for a Breakfast Quality Index (BQI) for children and adolescents. Public Health Nutrition. 16 (4): 639-644.
Monzani A, et al. 2019. A systematic review of the association of skipping breakfast with weight and cardiometabolic risk factors in children and adolescents. What should we better investigate in the future? Nutrients. 11 (2): 387.
Narciso J, et al. 2019. Behavioral, contextual and biological factors associated with obesity during adolescence: a systematic review. PloS one. 14 (4).
O'Neil CE, et al. 2014. The role of breakfast in health: definition and criteria for a quality breakfast. Journal of the Academy of Nutrition and Dietetics. 114 (12): S8-S26.
Onis Md, et al. 2007. Development of a WHO growth reference for school-aged children and adolescents. Bulletin of the World Health Organization. 85: 660-667.
Pereira JL, et al. 2018. Prevalence of consumption and nutritional content of breakfast meal among adolescents from the Brazilian National Dietary Survey. Jornal de Pediatria. 94 (6): 630-641.
Raj M & Kumar RK 2010. Obesity in children & adolescents. Indian Journal of Medical Research. 132 (5): 598.
Rampersaud GC, Pereira MA, Girard BL, Adams J & Metzl JD 2005. Breakfast habits, nutritional status, body weight, and academic performance in children and adolescents. Journal of the American Dietetic Association. 105 (5): 743-760.
Rashidi A, et al. 2007. Obese and female adolescents skip breakfast more than their non-obese and male peers. Open Medicine. 2 (4): 481-487.
Rasmussen M, et al. 2006. Determinants of fruit and vegetable consumption among children and adolescents: a review of the literature. Part I: quantitative studies. International Journal of Behavioral Nutrition and Physical Activity. 3 (1): 22.
Rodrigues PRM, et al. 2016. Irregular breakfast habits are associated with children’s increased adiposity and children’s and parents’ lifestyle-related behaviors: a population-based cross-sectional study. Nutrire. 41 (1): 8.
Saikia D, Ahmed SJ, Saikia H & Sarma R 2016. Overweight and obesity in early adolescents and its relation to dietary habit and physical activity: A study in Dibrugarh town. Clinical Epidemiology and Global Health. 4: S22-S28.
Schusdziarra V, et al. 2011. Impact of breakfast on daily energy intake-an analysis of absolute versus relative breakfast calories. Nutrition Journal. 10 (1): 5.
Utter J, Scragg R, Schaaf D & Mhurchu CN 2008. Relationships between frequency of family meals, BMI and nutritional aspects of the home food environment among New Zealand adolescents. International Journal of Behavioral Nutrition and Physical Activity. 5 (1): 50.
World Health Organization 2016. BMI for age (5-19 years) https://www.who.int/growthref/ who2007_ bmi_for_age/en/
World Health Organization 2018. Obesity and Overweight; https:// www.who.int/ news-room/ fact- sheets/ detail/obesity-and-overweight.
Yang R-J, Wang EK, Hsieh Y-S & Chen M-Y 2006. Irregular breakfast eating and health status among adolescents in Taiwan. BMC Public Health. 6 (1): 295.