The toddler stage (i.e., one to four years of age) is a highly influential time in the prevention of obesity in children. In this issue ofAmerican Family Physician, Allen and Myers provide valuable information on dietary intake of milk and other beverages, fats, and vitamin and mineral supplements, as well as recommendations on how to develop a healthy eating pattern for toddlers.1
Although it has been proven that overweight children are likely to become overweight or obese adults,2 few published studies on prevention of obesity have been conducted in toddlers. Findings from a longitudinal growth study of 3,650 full-term, healthy infants who were followed from birth showed that a body mass index (BMI) of 19 kg per m2 in boys and 19.5 kg per m2 in girls at three years is associated with a 50 percent risk of overweight (BMI greater than 25 kg per m2) at 18 years.3 Children with a low weight at two years who had large increases in BMI between two and 12 years were found to be at increased risk of developing impaired glucose tolerance or diabetes in young adulthood.4 The latter findings suggest that BMI monitoring during childhood with subsequent intervention as necessary may help prevent diabetes in adulthood. Furthermore, elevated BMIs in nonobese two- and three-year-olds are associated with higher fasting insulin levels, which are associated with higher levels of C-reactive protein.5 Because of the low success rates of adult obesity treatments, prevention approaches aimed toward children are needed urgently.
In addition to genetic contributions, environmental and lifestyle factors play important roles in the rapid increase in obesity incidence over recent years.6 Because eating and physical activity practices are formed early in life and may be carried into adulthood, prevention programs for children that encourage increased physical activity and healthy eating habits must be developed and tested. Potential critical periods when obesity may be triggered include the intrauterine period, the first year of life, preschool to school age (a period of increasing BMI, or adiposity rebound), and adolescence.7
Monitoring growth and recognizing changes in growth patterns (e.g., moving into a higher BMI percentile) with subsequent intervention to reverse these changes are the first steps toward preventing childhood obesity.8 Excessive weight gain relative to linear growth can be identified easily during a routine examination or by parents at home. Parents can easily monitor the weight and height of their child, calculate the BMI, and plot it on a growth chart. A change in the direction of BMI should be communicated to the physician before the onset of severe overweight or malnutrition.
For toddlers with no known risk factors for developing obesity (e.g., normal birth weight, no family history of obesity), parental modeling of proper nutrition and physical activity is likely to have the greatest influence on weight and health maintenance. A recent guideline from the American Heart Association provides dietary strategies for children and adolescents to improve nutrition early in life, with an emphasis on parental responsibilities such as the provision of quality nutrition and avoidance of excess caloric intake in toddlers.9 Pressuring children to eat and restricting access to specific foods are not recommended because they could lead to overfeeding and affect a child’s behavioral response to food selection and intake.10,11
Physicians have several options that can be used to promote physical activity, such as asking about activity patterns, counseling parents on the importance of being role models for active lifestyles, advising limits for sedentary activities, suggesting the use of activities instead of food as rewards; and recommending activities specific to the child’s age.12 However, because of the limited time for health maintenance visits, a take-home brochure could be used to provide strategies on how to eat a healthy diet and be more physically active. At a minimum, the measurement of BMI and a discussion of the child’s BMI should occur.
For children at risk of obesity (e.g., those with a high birth weight or with parents who are overweight and have a sedentary lifestyle), the underlying predisposing factors should be discussed with parents. Parents should receive educational or consultation programs from health care professionals to help them manage their child’s weight so that the toddler is provided with a risk-free family environment. Dietary and physical activity interventions could commence after an increase in the BMI percentile has been observed in at-risk children. Children with a BMI greater than the 95th percentile for sex and age should undergo blood pressure, fasting insulin, and glucose level measurements; lipoprotein analysis; and evaluation for other obesity-related complications.12
Although data from intervention studies in toddlers are extremely limited, efforts aimed at preventing at-risk toddlers from gaining excess weight may help delay the timing of adiposity rebound, which has been reported to be a risk factor for adult obesity.13