Most of the respondents’ parents had at least secondary education (78.5%). This is consistent with the findings of a similar study in Ibadan, Nigeria where 89.2% and 94.6% of the mothers and fathers had at least secondary education. 25
Less than one third (31.0%) of the adolescents had good knowledge of balanced diet but the majority (76.1%) knew the common food sources of energy and protein. This agrees with a similar study in Abuja municipal area, wherein 34.8% of the adolescents had good knowledge of balanced diet. 26 It is possible that the adolescents had learnt about common food sources in school through subjects like physical and health education, home economics as well as food and nutrition. In contrast, less than half of the adolescent girls in rural Bangladesh, knew common food sources of energy and protein.15 The higher knowledge among adolescents in Lagos could be because Lagos is an urban area where adolescents are probably more exposed to media adverts, television and internet compared to ‘rural Bangladesh’.
Overall nutritional knowledge was poor; only 12.0% of the adolescents had good level of overall nutritional knowledge. This is consistent with the report of a similar study in Sokoto, Nigeria where only 29% of adolescents had good level of nutritional knowledge. 27 This implies that Nigerian adolescents don’t have substantial knowledge and understanding of healthy food choices, energy and nutritive values of foods and dietary related diseases. Detailed explanation of healthy food choices, energy and nutritive values of foods and dietary related diseases maybe absent from the school curriculum. On the contrary, a Tehranian study reported good nutritional knowledge among 82% of the girls and 75% of the boys. 28 This could be because adolescents in Asia are more exposed than those in Nigeria. Good nutritional knowledge is important because it usually has a positive influence on healthy food choices and health.29 This was demonstrated in this study because the level of knowledge was significantly associated with the nutritional status of the adolescents. Most of the adolescents who had good nutritional knowledge were within the normal range of Body Mass Index. This finding similar to that of another study in India where nutritional knowledge had great impact on the health status of adolescents. 30
According to this current study, sex and age were positively associated (p < 0.05) with level of nutritional knowledge. The males and younger adolescents exhibited better nutritional knowledge than the females and older adolescents. This is similar to the findings from another study in rural Bangladesh15 where age, and other socio-demographic characteristics were positively associated with nutritional knowledge. It however contrasts with the report from a similar study in Sokoto state, Nigeria 28 where the females had better overall nutritional knowledge than males. This current research shows that females do not always have better nutritional knowledge.
Various forms of malnutrition have been associated with adolescents’ dietary patterns which make them predisposed to obesity and non-communicable diseases. Majority (84.9%) of adolescents in this study had 3–4 main meals per day. This could be because they lived with their parents who monitor their feeding. This finding is corroborated by another report from urban Baroda, India, where 55% of the adolescents took regular meals 3 times a day, (4) but contrasts with the report from adolescent girls in Saudi-Arabia 31 where 44.7% of the adolescents had 2–3 main meals in a day and
Skipping of breakfast was reported among 33.0% of the adolescents and done five times more often compared with dinner (5:1). This is consistent with another report from Saudi-Arabia where 40.0% skipped breakfast and other Nigerian studies where the rate of breakfast skipping is higher than lunch and dinner. 31, 32 However, in India 55% of adolescents have a good habit of taking regular meals thrice a day and did not skip a single meal in a week.4 Adolescents generally have poor habits of breakfast skipping irrespective of their geographical location. Some reasons for missing meals as explored by other studies include little time for meal preparation, ill health, lack of appetite, or disliking the food served. 27
Adolescents’ concern about body image has been linked with breakfast skipping and social pressures to achieve a distorted body image, is creating malnutrition among some groups of adolescents.17 About 45% of rural adolescents in India suffer from under-nutrition with Body Mass Index (BMI)< -2SD. 33 Irregular meal patterns and breakfast skipping are associated with obesity.5, 6 The consequences of poor dietary habits such as skipping breakfast, include poor academic performance on standardized tests, absenteeism and tiredness. 34
Daily consumption of snacks (69.6%) and carbonated drinks (46.8%) were common among the adolescents. These findings are similar to reports from Sokoto where 82.1% of the students reported daily consumption of snacks though a lower prevalence was obtained in Osun state (33.2%).20, 29 This finding agrees with a Ghana study where majority of adolescents were reported to have Sweet Tooth Patterns (STPs).35 Adolescents commonly indulge in unhealthy dietary practices. When adolescents skip meals, they often make poor decisions such as consuming less fruits and vegetables, buying fast foods or unhealthy snacks which lead to weight gain and ultimately diabetes and heart disease later in life. 3
The WHO survey among Oman adolescents reported that some foods that were used for snacks included carbonated drinks (33.4%) and fast foods (10%), which mostly are purchased outside the home. This practice of snacks use is becoming more common in societies due to westernization and especially among those who spend long hours outside home. 36
Dietary intake of adolescents in developing countries like Nigeria and Ghana is a major concern, because traditional diets (predominantly cereal and tuber based, fresh fruits and vegetables and foods low in fat) are gradually giving way to more westernized diets which lack diversity and are high in calorie. The reason for increased consumption of snacks can be because the adolescents have some amount of money available to them for daily spending, and that these unhealthy snacks and soft drinks are relatively affordable and comfortably fits in their budget.
Consumption of high-sugar, fat and salty snacks was high among the adolescents because of ready availability and affordability of the snacks. Consistent with previous studies, the choice of fast food among adolescents was influenced by taste, convenience and cost. Most fast foods with the qualities of good taste, convenience and low cost, usually have a high fat and sugar content but low fiber content which promotes obesity.36 Consumption of snacks is a general issue among adolescents irrespective of their countries or localities. Although snacking is not completely bad, the quality of snacks chosen is very important. Carbonated soft drinks are energy dense and have a high glycemic index.36 Some studies have linked high soft drink consumption rate to poor intake of calcium, vitamin C and increased risk of bon e fractures because of its acidity.36
Cereals especially rice (73.5%) and pastries (69.6%) were the most commonly consumed group of foods. This finding correlates with other studies from South-western Nigeria (76.5%), Ethiopia (99.6%) (97.6%) and India (50%) where rice and pastries were commonly consumed by adolescents compared with other foods.4, 37, 38 Refined cereals like processed rice and pastries have little or no fiber and contribute to the prevalence of obesity. They contribute significantly to the higher intakes of Advanced Glycation End-products (AGEs) which is associated with marginally greater weight gain. The top six food groups contributing to AGEs intake are cereals/cereal products, meat/processed meat, cakes/biscuits, dairy, sugar and confectionary and fish/shellfish. 39
A higher proportion of older adolescents were underweight, overweight and obese compared with younger adolescents. This may be because many of the older ones engaged in dieting and skipping of meals compared with the younger adolescents. This finding is a contrast to the results obtained from similar studies in India and Ibadan, Nigeria where higher proportion of the younger adolescents were underweight (p < 0.001). 4, 20
Females had higher prevalence of overweight (13.9) and obesity (8.4%) compared with males (6.6% and 4.3%) similar to the reports from Sokoto and Ethiopia studies.27, 37 The higher prevalence of obesity among the girls may be related to weight gain that results from developmental changes and hormonal influences which necessitates beginning of menarche in females. In addition to the hormonal influences, gender roles particularly those requiring higher physical exertion can also affect weight. Boys participate more in physical activities which necessitate energy utilization compared with girls, thereby aiding expenditure of consumed calories, and reduction of fat accumulation. However, some other studies have reported contrasting reports wherein more boys had higher prevalence of overweight than girls (19.4 vs 13.2%; p < 0.05). 4
Infrequent intake of fruits (456, 66.9%) and skipping meals to control weight (254, 38.7%) were positively associated with higher prevalence of overweight and obesity while dieting to control weight (365, 53.5%) was positively associated with underweight. However, there was no statistically significant association between the number of main meals eaten per day and nutritional status of the participants (p = 0.0508).
Only 9.7% of the adolescents consumed adequate fruits and vegetables (F&V) (400 g or 5 servings) daily. This is not surprising since only 27.0% of the adults in Lagos consumed an adequate amount of F&V daily. Consumption of F&V is usually lower among adolescents due to inadequate knowledge about their benefits, family practice of irregular fruits intake, dislike of the taste of some fruits and others. In this study, low consumption of fruits and vegetables was associated with overweight and obesity. This correlates with the report from a similar study in Benin City, where low consumption of fruits and vegetables was associated with overweight. 32
Only 30.4% of the respoendents had high dietary diversity, similar to the report among Zimbabwe and Tehranian adolescents where less than 50% of adolescents had high dietary diversity.40 Based on the nine item FAO Dietary Diversity Score (WDDS); dietary diversity is regarded as high and more likely to meet micronutrient needs if four or more food groups are consumed per day whereas dietary diversity is poor if three or less food groups are consumed per day.41 In this study, good dietary diversity was associated with normal body mass index and decreased prevalence of underweight, overweight and obesity(p < 0.001). This correlates with the fact that adequate dietary diversity indicates that significantly higher intakes of most key nutrients are consumed and available for the body to maintain a normal nutritional status. 42
Number of meals consumed per day was not associated with the nutritional status of the adolescents. This agrees with some other studies which have demonstrated that no of meals does not affect weight status but contrasts the findings in a similar study in Saudi-Arabia where 13.0% of those who consumed more than four meals per day were overweight and obese. 31
Few adolescents, 5.4% were undernourished, 78.6% were of normal weight, while 10.7% and 5.3% were overweight and obese respectively. The prevalence of obesity among Lagos adolescents is quite higher than the rate in other parts of Nigeria such as Ibadan (0.8%), Ondo (0.96%) and Port Harcourt (1.8%).10, 19, 43 Nutritional status of adolescents is very important, because they are highly susceptible to malnutrition which can have impact on their offspring in the future.44