While everyone thinks a chubby baby is a cute baby, that cute chubbiness could be the beginning of big problems in children. New research suggests that the tendency for childhood obesity may begin in infancy.

Over the past thirty years the prevalence of childhood obesity in the United States has more than doubled for young children and adolescents, and tripled for children ages 6 to 11. Currently, an estimated 17 percent of children and adolescents ages 2 to 19 are obese. Childhood obesity is associated with the early development of chronic diseases such as hypertension, cardiovascular disease, and type 2 diabetes.

No one is suggesting that infants or young children be put on a diet. Whether breastfed or bottle-fed, infants should never be denied their feeding. As solid foods are introduced, usually between the ages of 4 and 6 months, parents should make healthy choices for their children.

According to the Centers for Disease Control (CDC), obesity in children is defined as a body mass index (BMI) at or above the 95th percentile for children of the same age and sex on the 2000 CDC Growth Charts. Overweight is defined as a BMI at or above the 85th percentile.

Researchers studied data from the Early Childhood Longitudinal Study-Birth Cohort to track the weight of about 7,500 children who were born in 2001. At the age of 9 months, 32 percent of the infants were either obese or at risk of obesity. By the time the infants were 2 years old, that figure increased to 34 percent.

Head researcher Brian Moss of Wayne State University in Detroit said, "We weren’t surprised by the prevalence rates we found in our study, but we were surprised the trend began at such a young age."

Moss also said that while these results do not mean overweight babies will become obese adults, it could predict obesity later in childhood.

Other results from the study found that boys and Hispanic children had the highest risk of becoming obese, and girls and Asian/Pacific Islanders had the lowest risk. Geographic location was not consistently associated with being obese or at risk of obesity. The socioeconomic status of the family was not a factor at 9 months of age, but at the age of 2 years children in the lowest economic levels were most likely to be obese or at risk while those in the top economic levels were least likely.

Understanding the demographic characteristics of infants and young children who are more likely to become obese could foster the efforts of health officials as they try to develop policies and programs to fight childhood obesity, and it could encourage parents to promote healthy eating and lifestyle choices for their infants and children.

Despite the results of this study, no one is suggesting that infants or young children be put on a diet. Ideally, infants should receive breast milk exclusively for the first six months of life. Whether breastfed or bottle-fed, infants should never be denied their feeding. As solid foods are introduced, usually between the ages of 4 and 6 months, parents should make healthy choices for their children. Junk food, fast food, and other high calorie foods with low nutrient density should not be introduced until a child has had the opportunity to establish healthy eating habits.

The study appears in the January-February 2011 issue of the American Journal of Health Promotion.