The development of overweight and obesity during the early years of life is influenced both by child characteristics and by factors related to the child’s parents and home environment. Childhood obesity develops when the body’s self-regulatory system fails to modulate environmental influences relative to the person’s genetic background. Since it is not possible for the gene pool to change in less than a generation, it is likely that changes in nutrition and lifestyle are primarily responsible for the current epidemic of obesity.
Obesity develops when there is an imbalance between energy intake and energy expenditure: reduced physical activity and increased food intake (especially high-fat, energy-dense foods such as snacks, sugar-added beverages and fast-food products) are the primary causes. In young children, levels of physical activity lower than the recommended 60 minutes per day and excessive television viewing (more than two hours per day) are likely to have adverse effects on cardiovascular and bone health, and possibly on cognitive function and social and emotional development.
Prenatal factors that may lead to overweight in children from birth to five years include maternal smoking, maternal diabetes, and maternal overweight prior to and during pregnancy. Breastfeeding, however, may protect children from obesity. Possible mechanisms for this protective effect include metabolic programming and early-learned self-control of food intake. Another possible explanation is that breastfeeding may influence parental control of child consumption patterns. As well, breastfed babies experience a variety of flavours through the mother’s diet, which may make them more accepting of typically rejected foods (such as vegetables) later on.
Introduction to complementary foods (cereal, fruit, vegetables or meat) before 16 weeks of age in combination with a short duration of breastfeeding (less than 20 weeks) has been associated with higher weight gains from birth to one year. Studies suggest that the late introduction of solids (waiting until at least 15 weeks of age) may have a beneficial effect on childhood obesity and reduce the risk for allergic reactions. Rapid weight gain in infancy and early childhood appears to be a risk factor for later obesity.
Parents have a major role to play in helping their children to develop healthy eating habits and an active lifestyle. Since children imitate what they see, it is not surprising that parents’ own eating behaviours are associated with children’s eating behaviours and weight status. Children naturally prefer sweet and salty tastes and do not need to learn to like these foods. However, when given the opportunity to taste new foods repeatedly, such as fruits and vegetables, children learn to like foods they once rejected. Studies have shown that it may take 5 to 16 exposures before a child accepts a new food.
While it is advisable for parents to limit their children’s consumption of unhealthy snacks and encourage them to eat more fruits and vegetables, excessive restriction or pressure to eat may actually have negative impacts on child food intake and weight status by disrupting the child’s ability to naturally control their food intake. Parental pressure to eat certain foods may decrease the children’s preferences for those foods, while excessive restriction may encourage over-consumption of the restricted foods when they are readily available.
Finally, psychosocial factors that potentially increase the risk that a child will become obese include low socio-economic status, being an only child, and living with a single parent.
|