Documentary Asks How Body-Size Bias Affects Obesity Research

By Medscape Staff

November 19, 2021

Framing evidence of positive health associations with obesity as "paradoxical" can limit pathways to new research, a short new film suggests.

What to know:

  • How do biases about body size affect obesity research and what information do people accept as true? These are the questions asked by "What's in a Number?" a short documentary by Retro Report and Scientific American.

  • In 2005, Katherine Flegal, PhD, then a senior scientist at the Centers for Disease Control and Prevention, led a study suggesting that the rate of annual deaths from obesity in the United States was about 100,000 – in contrast to a popularly cited statistic putting that number at 300,000 – and that people considered overweight had a longer life expectancy than those in the normal weight category.

  • However, Flegal's research was met with widespread criticism, and the figure of 300,000 annul deaths continues to be regularly cited in newspapers, medical journals, and legislation.

  • According to the documentary, results that seem to contradict the belief that thinner is always healthier are frequently labeled with the phrase "obesity paradox," which always frames the results as unexpected.

  • Grouping results under the "obesity paradox" label can cause disbelief around findings and limit new research, says cancer researcher Bette Caan, DrPH, whose own research suggests that prioritizing retaining muscle during treatment is more important for patients with breast cancer than avoiding weight gain.

This is a summary of the article, "The Weight Game: How Body-Size Bias Can Hold Back Health Science," published by Scientific American on November 18, 2021. The full article can be found on

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