Self-reported BMI bias estimates increasing due to weight bias, not weight loss

The gap between obesity levels measured by self-reported height and weight and obesity recorded by measured height and weight is increasing. This is due to an increasing bias in self-reported weight, according to research published January 23 in the open access journal PLOS ONE by Frances Shiely and colleagues from University College of Cork, Ireland.

BMI is a ratio of height and used clinically to assess whether an individual's weight is in a healthy range. Previous studies have shown that people tend to over-estimate their own height and under-estimate their weight and it is generally assumed that both are responsible for under-estimation of self-reported BMI. The authors of this study have shown in previous work that under-estimation of BMI is increasing over time. Here, they assess whether this increasing inaccuracy is due to changing biases in self-reported height, weight, or both, using data from a representative sample of Irish adults.

The researchers found that the in self-reported height has remained stable over the last ten years regardless of gender, age or clinical BMI category. However, biases in self-reported weight have increased over time for both genders and in all age groups. The bias towards reporting a lower weight is most notable in those who are obese.

The authors state that knowing why self-reported scores are decreasing while clinically measured BMIs are not "brings us one step closer to accurately estimating true obesity levels in the population."

More information: Shiely F, Hayes K, Perry IJ, Kelleher CC (2013) Height and Weight Bias: The Influence of Time. PLoS ONE 8(1): e54386. doi:10.1371/journal.pone.0054386

add to favorites email to friend print save as pdf

Related Stories

Most people fudge numbers on weight and height surveys

Jan 27, 2012

When people in the U.S. are asked to provide their weight for research surveys, they underestimate their weight and overestimate their height, despite numerous public reports about increasing rates of obesity. ...

Rethinking body mass index for assessing cancer risk

Nov 08, 2012

A study by researchers at Albert Einstein College of Medicine of Yeshiva University suggests that body mass index (BMI)—the most commonly used weight-for-height formula for estimating fatness—may not be the best measure ...

Recommended for you

Weight training appears key to controlling belly fat

51 minutes ago

Healthy men who did twenty minutes of daily weight training had less of an increase in age-related abdominal fat compared with men who spent the same amount of time doing aerobic activities, according to ...

When you lose weight, where does the fat go?

Dec 16, 2014

Despite a worldwide obsession with diets and fitness regimes, many health professionals cannot correctly answer the question of where body fat goes when people lose weight, a UNSW Australia study shows.

User comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.