http://www.cdc.gov/obesit/data/childhood.html

Childhood Obesity Facts

The prevalence of obesity among low-income children aged 2 through 4 years, by state and income, 2011

Prevalence of Childhood Obesity in the United States, 2011-2012

Childhood obesity is a serious problem in the United States. Despite recent declines in the prevalence among preschool-aged children, obesity among children is still too high. For children and adolescents aged 2-19 years, the prevalence of obesity has remained fairly stable at about 17% and affects about 12.7 million children and adolescents for the past decade. [Read abstract Journal of American Medical Association (JAMA)]

Approximately 17% (or 12.7 million) of children and adolescents aged 2—19 years are obese
The prevalence of obesity among children aged 2 to 5 years decreased significantly from 13.9% in 2003-2004 to 8.4% in 2011-2012.

In 2011-2012, 8.4% of 2- to 5-year-olds had obesity compared with 17.7% of 6- to 11-year-olds and 20.5% of 12- to 19-year-olds.Childhood obesity is also more common among certain racial and ethnic groups.

In 2011-2012, the prevalence among children and adolescents was higher among Hispanics (22.4%) and non-Hispanic blacks (20.2%) than among non-Hispanic whites (14.1%).
The prevalence of obesity was lower in non-Hispanic Asian youth (8.6%) than in youth who were non-Hispanic white, non-Hispanic black or Hispanic.

Note: In children and adolescents age 2 to 19 years, obesity was defined as a body mass index (BMI) at or above the 95th percentile of the sex-specific CDC BMI-for-age growth charts.

Childhood obesity is associated with adult head of household’s education level for some children

[Read the report Obesity–United States 1999–2010, in MMWR]

Obesity prevalence differs among racial/ethnic groups and also varies by age, sex, and adult head of household’s and education level.
Overall, obesity prevalence among children whose adult head of household completed college was approximately half that of those whose adult head of household did not complete high school (9% vs 19% among girls; 11% vs 21% among boys) in 1999–2010.
Among non-Hispanic white children, the lowest prevalence of obesity was observed among those whose adult head of household completed college; however, this was not the case for non-Hispanic black children.
Over time, the prevalence of obesity among girls whose adult head of household had not finished high school increased from 17% (1999–2002) to 23% (2007–2010), but decreased for girls whose adult head of household completed college from 11% (1999–2002) to 7% (2007–2010). There was not a similar finding among boys.

Childhood obesity among preschoolers is more prevalent among those from lower-income families

[View the table:The prevalence of obesity among low-income children aged 2 through 4 years, by state and income, 2011]

The prevalence of obesity among children aged 2–4 years from low-income households in 2011 varied by levels of income-to-poverty ratio,* which is a measure of household income.
Obesity prevalence was the highest among children in families with an income-to-poverty ratio of 100% or less (household income that is at or below the poverty threshold), followed by those in families with an income-to-poverty ratio of 101%–130%, and then found to be lower in children in families with an income-to-poverty ratio of 131% or larger (greater household income).
Obesity prevalence on the basis of family income among children from low-income households was:
- 14.2% among children in families with an income-to-poverty ratio of less than or equal to 50%.
- 14.5% among children in families with an income-to-poverty ratio of 51–100%.
- 13.4% among children in families with an income-to-poverty ratio of 101–130%.
- 12.4% among children in families with an income-to-poverty ratio of 131–150%.
- 11.8% among children in families with an income-to-poverty ratio of 151-185%.
There were differences in state-level childhood obesity estimates by income-to-poverty ratio (refer to table).

* Income-to-poverty ratios reflect family income in relation to poverty threshold. The poverty level varies by family size, the number of related children, and the age of the head of household, but not by state. For example, a family of four with two children and an annual income of $22,811 were at the poverty level in 2011. For income-to-poverty ratios less than 100%, the family income is lower than the poverty threshold. When the ratio equals 100%, the income and poverty level are the same, and when the ratio is greater than 100%, the income is higher than the poverty level. A ratio of 130% indicates that family income was 30% above the poverty level.
Note: Obesity prevalence was estimated by state and income-to-poverty ratio using information from the Pediatric Nutrition Surveillance System (PedNSS). PedNSS contained measured heights and weights, as well as other information from low-income children aged 2–4 years. The source of the PedNSS data was from federally funded maternal and child health and nutrition programs, with data primarily collected through the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC).

Obesity and extreme obesity rates decline among low-income preschool children

[Read Journal of American Medical Association (JAMA) study highlights (PDF - 143 KB) ]
[Read article Journal of American Medical Association (JAMA) ]

Obesity and extreme obesity* among US low-income, preschool-aged children went down for the first time in recent years.
From 2003 through 2010, the prevalence of obesity decreased slightly from 15.21% to 14.94%. Similarly, the prevalence of extreme obesity decreased from 2.22% to 2.07%.
However, from 1998 through 2003, the prevalence of obesity increased from 13.05% to 15.21%, and the prevalence of extreme obesity increased from 1.75% to 2.22%.
Extreme obesity decreased among all racial groups except American Indians/Alaska Natives. The greatest decreases were among and Asian/Pacific Islander children and 2-year-old children.

* A child's weight status is determined using an age- and sex-specific percentile for BMI rather than the BMI categories used for adults because children's body composition varies by age and sex. The weight status of children is defined on the basis of the sex-specific smoothed percentile curves for BMI-for-age in the 2000 CDC growth Charts. Extreme obesity is defined as a BMI at or above the 120% of the 95th percentile for children of the same age and sex. For example, a 3-year-old boy of average height who weighs more than 44 pounds would be classified as extremely obese