The growing epidemic of child and youth obesity--another twist?

The state of childhood obesity in Canada and many countries worldwide has reached epidemic proportions. The Canadian prevalence has tripled from 1981-1996. A stunning 40% of obese children and 70% of obese youth continue this trend into adulthood. This has led to higher rates of adult obesity and associated conditions such as type 2 diabetes and cardiovascular disease. A chronically positive energy balance causes obesity, where energy intake exceeds expenditure. Although genetic heritability may account for 25-40% of childhood obesity, it would be hard to imagine that recent mutations have accounted for the epidemic rise in rates over the past 20 years. Clearly, environmental factors must play a significant role. Most important among these are inappropriate nutrition and inadequate physical activity. Canadians ingest large amounts of refined sugar and fat-containing foods. The most popular Canadian beverage is the soft drink with greater than 110 litres consumed per person per year. With their busy schedules, families rely more readily on meals from fast food restaurants where large portions of fatty foods are consumed. Eating while watching television is also associated with weight gain, and excessive sedentary activities, such as television watching and playing video and computer games are more prominent than ever. Recent statistics show that children and youth watch up to14 hours per week of television and spend an average of 6-7 hours per day viewing various media. Eighty percent of Canadian children have Internet access at home and almost 50% are online for at least an hour per day. In addition, children are not engaged in sufficient amounts of regular physical activity. At least half of Canadian children are not physically active enough for optimal growth, and development and levels of activity drop as they get older. Adolescents are on average 10% less physically active than children 2-12 years of age. Girls are less active, and do less physically intense activities than boys. The reduction in physical activity levels begins 2 years earlier in girls (14-15 vs 16-17 years) compared with boys. Hypoactivity is even more prevalent in obese children and youth, which results in less energy expenditure and more weight gain. Unfortunately, obese children and youth are not just “out of shape”. Over the last 10-20 years, these individuals have developed a number of chronic illnesses including type 2 diabetes, hypertension, hyperlipidemia, respiratory disorders, gallbladder disease, orthopaedic problems and, not inconsequentially, psychological illness. Obesity is associated with poor self-esteem and depression, and when depression is noted in non-obese youth there is a two-fold increase in risk of obesity within one year. Body image and “fitting in” with perceived norms of weight, height and sexual development are important concerns for adolescents. Heavy-set youth in a state of poor self-worth frequently try to lose weight by adopting various calorie-restricted diets, which are ultimately ineffective and usually result in greater weight gain. This leads to a vicious circle of inadequate self-esteem, high levels of physique anxiety and unhealthy behaviours. In this issue of the Canadian Journal of Public Health, Peter Crocker’s article entitled “Predicting Change in Physical Activity, Dietary Restraint, and Physique Anxiety in Adolescent Girls: Examining Covariance in Physical Self-Perceptions” looked at the relationship between changes in these elements prospectively over a one-year period using several questionnaires. There are a number of limitations to this study including the lack of objective measurements of height, weight and physical activity. Also, there was a 10% drop out of subjects, which might have an impact on data analysis. In addition, the paper is exploratory in nature and as such, causation cannot truly be determined. However, a number of interesting associations were reported. Statistically significant small increases in mean body mass index (BMI) and social physique anxiety were noted in this study. Intriguingly, rising BMI values over the 12 months did not predict a change in physical activity, social physique anxiety, physical self-perceptions or dietary restraint. A reduction in physical activity was associated with changes in all self-perceptions except BMI. However, worsening of perceived physical conditioning was the only significant predictor. Body appearance, especially perceived physical conditioning, was linked to increases in social physique anxiety and dietary restraint, independent of BMI. This implies that factors other than actual height, weight and percent body fat may play a role in the development of negative self-perceptions resulting in significant aberrations in nutritional intake. One of these factors is likely the media in today’s society. Research has shown that in girls, the development of a negative body image appears to be strongly linked to media images of the thin female role model. Interestingly, young people are often unaware that the fashion industry uses digital enhancement and airbrush techniques to make these models look “perfect”. It is no wonder that obese teens become increasingly frustrated trying to achieve these unrealistic standards by ineffective and potentially harmful weight-losing behaviours. If we hope to stop the epidemic of obesity in Canada, fad diets are undoubtedly not the answer. Instead, a focus on healthy active living within families, schools, communities, and all levels of government must be adopted. Healthy food choices should be promoted. These include restricting soft drink and juice intake in childhood, increasing the intake of carboFaculty of Medicine, University of Ottawa Correspondence: Dr. Claire M.A. LeBlanc, Department of Pediatrics, Children’s Hospital of Eastern Ontario, 401 Smyth Road, Ottawa, ON K1H 8L1