For generations, people from around the world were struggling with food scarcity due to poverty and diseases associated with this problem. However, with the onset of the industrial revolution in the 18th and 19th century it became clear that in order to gain economic development and increase productivity, there had to be a shift in the population’s body mass index (BMI), going from being underweight to normal weight.
Therefore, a new approach of adding sugar and fat to one’s usual diet began, which resulted in a progressive increase in both height and weight, predominantly during the 19th century. From this point forward, the obesity epidemic has seen a general increase in both overweight and obesity among adolescents in the last three decades. This has happened alongside the advances in technology and the changes in foods and its availability.
Not only has a large proportion of the world’s population now become car dependent, which means that adolescents therefore are no longer walking or cycling to and from school, but is being taken by car; but food high in sugar and fat has also become cheaper and the portions have become bigger. This has enabled adolescents to become more sedentary and eat more energy dense foods which therefore contribute to the high prevalence of overweight and obesity.
Thus, the prevalence of adolescent obesity is rapidly increasing and is not limited to a single continent, but has become a global epidemic. It has reached the level where worldwide policy makers, schools, parents, and the adolescents themselves have become worried. This worry is not only related to being overweight or obese, but also about the plethora of associated co-morbidities and nevertheless the health costs connected to this epidemic.
Yet, because adolescence is not only characterised by physical changes, but also by the development of individuals’ self-regulatory skills due to becoming more autonomous this can have a strong impact on their health behaviours. Hence, it is a critical time to address the issue of overweight and obesity as research suggests that the health behaviours developed in adolescence are likely to persist into adulthood.
In addition, obesity in general is suggested to cause serious health issues which can impact virtually every organ in the body. These health issues often have severe consequences; thus, result in increased morbidities and mortality rates. Consequently, an increased likelihood of adult mortality from a broad range of systemic diseases is prevalent when adolescents between the ages 14-19 are either overweight or obese.
Also, diseases such as diabetes type 2, hypertension and dyslipedidemia are well known among children and adolescents who are either overweight and/ or obese. Additionally, other complications for instance obstructive sleep apnea, nutritional deficiencies such as low vitamin D levels and insufficient iron intake, musculoskeletal problems and furthermore psychological distress such as depression are also extremely common in overweight and obese individuals. It is also suggested that nearly half of the adolescents who are considered obese, BMI ≥97th percentile have one or more conditions that constitutes metabolic syndrome.
According to the Health Survey for England, 2010 a whole 33.8% of all children aged 11-15 years are classified as either overweight or obese which is shocking. In addition, the Foresight report from 2007 has made projections about the obesity prevalence in the UK in 2050, which predicts that 26% of both females and males under the age of 20 years will be obese which means that 52% of all children and adolescents up to the age of 20 years will be obese.
However, the terms overweight and obesity can be ambiguous, in particular when classifying a child/adolescent to be either or, as different countries, organisations and journal articles have different definitions of both of the terms. Having different terminology can impact the reliability of the statistics of childhood obesity and in other words can make it more difficult to compare and contrast data. Also, the most widely used method for determining both individual and population fatness is BMI and although it has been around for a long time, it has only recently been developed to use on children and adolescents. Yet, it is questionable whether it is the most appropriate indicator of childhood and adolescence overweight and obesity as it does not give a direct measure of lean mass vs. fat mass nor does it give an indication of the distribution of the fat.
Also, because children and adolescents have growth spurts at different times, the BMI developmental curve does not fit every child and adolescent. For these reasons, BMI may show that a child is overweight according to their age and gender, but due to individuality in how children and adolescents grow and how much lean body mass they have, it can be difficult and unreliable to determine from a BMI score. Consequently, results should be interpreted with caution and if possible measurements such as waist circumference and skinfolds could help identify and understand variations in BMI. However, due to often having limited time and/ or resources BMI is typically used and seen as a “reliable” measure.