Prevention of childhood obesity should be a global public health priority due to the significant impact of obesity on acute and chronic diseases, general health, development and quality of life. The importance of childhood obesity for CVD development later in life has been convincingly demonstrated in a Danish study where height and weight data collected from 276,835 Danish individuals when they were children were related to data on CVD when they were adults. Here it was shown that the risk for any CVD event was positively and linearly associated with body mass index (BMI) for boys aged 7–13 years and girls aged 10–13 years, with a greater risk as age increased for both boys and girls [10].

Obesity as early as at the age of 5 years may lead to an increased prevalence of both type 1 and 2 diabetes mellitus at the age of 21 which was reported from a group of 2639 Australian young adult participants of the Mater-University study of pregnancy. The odds ratio for diabetes if there was overweight at 5 years amounted to 2.60 [11]. In addition, teenagers and young adults who are already obese or have type 2 diabetes have an increased carotid artery intima-media thickness and arterial stiffness [12]. Participants in this US study were more likely than the lean individuals to have other cardiovascular risk factors. Their risk factors correlated with both carotid IMT and stiffness but group was reported to be an independent predictor of common carotid artery IMT and for the beta stiffness index. Additional effects of type 2 diabetes and obesity appear to influence changes in the carotid structure and function beyond traditional risk factors.

Several direct and indirect methods of assessing overweight in children and adolescents have been proposed but body mass index and waist circumference can be recommended as the best measures for estimating adverse levels of blood lipids and blood. Müller and co-workers found that among children and adolescents with an elevated obesity index 20–30 % also had elevated levels in blood pressure and blood lipids. Their data did not support the statement that direct measures of fat mass or waist circumference exceed the value of BMI [13].

Are interventions aimed to improve diet or physical activity effective at preventing obesity in children? An updated analysis of a Cochrane Review included 55 childhood obesity prevention studies—an additional 36 from the previous Cochrane review—all with a duration of 12 weeks or more [14]. In this review strong evidence was found to support beneficial effects of child obesity prevention programs on BMI, particularly for programmes targeted to children aged 6–12 years. The review included 55 childhood obesity studies—an additional 36 from the previous review—all with a focus on prevention and a duration of 12 weeks or more. The team conducted a meta-analysis using available BMI or standardized BMI (zBMI) score data and subgroup analyses were performed by age group (0–5, 6–12, and 13–18 years). The interventions were generally effective at reducing adiposity; the overall mean reduction in adiposity (measured as BMI or zBMI) was 0.15 kg/m², with the largest reduction occurring among children aged 6–12 years. Thus there is nowadays sufficient scientific support for conducting prevention targeted programmes for childhood obesity.

Over the years the public awareness of nutrition high in saturated fat has resulted in an unfortunate increased use of high caloric carbohydrates. Many children and adolescents consume significant amounts of sweetened soft drinks. These are generally both cheap and everywhere accessible. The deleterious effects of a chronic caloric overload have become a major public health hazard. Welsh and co-workers found that adolescents who consume high amounts of added sugars have blood lipid levels that place them at a clearly increased risk for future CVD: increased dyslipidemia was observed among adolescents who had a high intake of added sugars, regardless of body size, as well as increased levels of insulin resistance among those who were overweight or obese. Therefore minimizing the consumption of added sugars in the young population is an important task both for parents as for society as a whole [15].

It is known that the maturing of the human brain takes mainly place in the first two decades of life. Could unhealthy nutritional habits influence this process, especially as diet supplies the nutrients needed for the development of brain tissues in early life? A study from Australia investigated the impact of diet on the intelligence quotient (IQ) by assessing data from 7097 children from the Avon Longitudinal Study of Parents and Children. They examined dietary patterns for the children using parental questionnaires completed at 6, 15, and 24 months of age and when the children were aged 8 years, the Wechsler Intelligence Scale for Children was used to measure IQ. A small but significantly higher IQ at 8 years was found when a healthy diet had been provided during the first 2 years of life [16].

With the growing access to electronic communication devices, smart phones etc, there is a tendency among children to become less active. Instead, children should be encouraged to increase their participation in physical activity, rather than reducing their time spent sedentary, to improve their cardiovascular health. Ekelund et al. pooled data from 14 studies involving more than 20,000 children (aged 4–18 years) and found that higher time spent on moderate to vigorous activity spent by children and adolescents was associated with better cardiometabolic risk factors regardless of the amount of sedentary time. They recommend to increase daily activity at this intensity level by participating in activities such as brisk walking, jogging, cycling, playing soccer, and other team sports [17].

Even maintaining a high level of fitness plays an important role as children and adolescents with higher levels of cardiorespiratory fitness (CRF) have reduced clustering of cardiometabolic risk factors. After assessing CRF and physical activity levels in 100 children and adolescents (aged 10–14 years) using a maximal cycle ergometer test and accelerometry, Bauley et al. used a clustered risk score. They found in comparing between fit and unfit participants, according to previously proposed health-related thresholds, that the fit group had a significantly lower mean clustered risk score than those in the unfit group (−0.74 vs 2.22, respectively) [18].

Keeping up physical activity and fitness may reduce the risk of type 2 diabetes mellitus as children grow into adulthood. A prospective Australian cohort study followed 647 adults who had participated in the Australian Schools Health and Fitness Survey in 1985 when they were aged 9–15 years and followed up in 2004–2006. The study showed that the decline in fitness and in physical activity which often can be seen in many teenagers is a stronger predictor of adult obesity and insulin resistance than low levels of fitness in childhood. Thus, efforts aimed at maintaining high childhood physical activity levels into adulthood may have a potential to reduce the burden of obesity and type 2 diabetes in adults [19].

Not all video and computer games seem to be hazardous, as has been considered previously. A research team from New Zealand randomized 322 overweight and obese children aged 10–14 years, who were current users of sedentary video games, to receive either an active video game upgrade or to have no change. After 24 weeks the active video game intervention had a small but significant effect on BMI and body composition in the overweight and obese children. As it is a challenge for many parents to protect children from an overdose of electronic toys it may be prudent to choose games that actually promote physical activity [20].