Contrary to what many people think, poorer American males are not more likely to be obese than their richer counterparts; but adult females nearer the poverty levels are, according to a new report issued by the National Center for Health Statistics. Rates of adult male obesity are fairly similar throughout all income levels, the authors reveal, with a slight increase among higher income men.

The number of obese adults in the USA has been growing steadily for the last few decades and does not appear to be slowing down. 72 million US adults are estimated to be either obese or overweight today. Over 30% of all American adults are obese.

A number of studies have associated obesity with socioeconomic and educational levels. Unfortunately, the media has often extrapolated from very limited studies and spread a general impression that obesity is the poor man’s epidemic.

For this latest report, the researchers gathered data from NHANES (The national Health and Nutrition Examination Survey), a cross-sectional survey designed to monitor the nutritional status and health of the civilian, non-institutionalized American population. A sample of 5,000 (nationally representative) people was used.

They found that 41% of all obese adults live in households that earn $77,000 or more per year – 350% of poverty-level income. 39% of obese adults live in households that earn from 130% to 350% of poverty-level income. The remaining 20% live in households whose income is below $29,000 per year (130% of poverty-level income). In all cases, household income relates to a family of four. The vast majority of obese American adults are not poor.

29% of adult males who live in households below 130% of the poverty level are obese, compared to 33% in well-off households (at least 350% of poverty-level income).

42% of adult females in households below poverty-level income are obese, compared to 29% in the more affluent homes.

Education appears to have a more constant correlation with obesity across both sexes:

  • 42% of adult females without a high school education are obese
  • 23% of adult females with a college degree are obese
  • 32% of adult males without a high school education are obese
  • 27% of adult males with a college degree are obese

There is a stronger link between obesity and household income among children, the authors reveal. 21.1% of boys and 19.3% of girls in poor households are obese, compared to 11.9% of boys and 12% of girls in well-off houses.

An obese person has a BMI (body mass index) of 30 or more. People with a BMI of between 18.5 and 24.9 are considered to be of normal weight. Those whose BMIs are between 25 and 29.9 are overweight. A person may be considered as obese if their bodyweight is at least 20% higher than it should be.

BMI is a measurement derived from a person’s height and weight.

  • BMI metric units
    Your weight (kilograms) divided by the square of your height (meters)
    For example. 80 kg weight. 1.8 meters height.
    1.82 meters = 3.24
    80 divided by 3.24 = a BMI of 24.69
  • Imperial units
    Pounds in weight times 703, divided by the square of your height in inches
    For example. 190lbs weight. 72 inches (6ft) height.
    722 = 5,184
    190 x 703 divided by 5,184 = A BMI of 25.76

BMI is not 100% reliable

Many people say that BMI does not measure fat and lean tissue content, and is thus unreliable. For example, a 6ft Olympic Gold Medal 100 meter sprint champion may have a BMI much greater than a 6ft couch potato. But the couch potato will have much more fat (which weighs less than muscle or lean tissue), a bigger waist, and is most definitely not likely to be healthier than the athlete – on the contrary.

BMI calculation may be useful if everyone in a study has similar levels of physical activity. Hip-waist ratio measurements are said to be much better indicators of people’s proximity to their ideal weight.

Written by Christian Nordqvist