People with low BMI are 'surprisingly' less active: report
July 15, 2022
Chinese researchers revealed in a new study that people with a very low body mass index (BMI) consume less food and are less active.
Before, people believed that a low BMI was linked to a fast metabolism that naturally makes them more active.
“We expected to find that these people are really active and to have high activity metabolic rates matched by high food intakes,” said study author John Speakman, a professor at the Shenzhen Institutes of Advanced Technology in China and the University of Aberdeen in the UK, in a media release.
“It turns out that something rather different is going on. They had lower food intakes and lower activity, as well as surprisingly higher-than-expected resting metabolic rates linked to elevated levels of their thyroid hormones.”
The researchers examined 173 volunteers with a normal BMI range and 150 that were “healthy underweight” for two weeks. Their food intake and physical activity was closely measured.
The researchers found that the healthy underweight participants ate 12% less food and were 23% less active than those with a normal BMI range.
“Although these very lean people had low levels of activity, their markers of heart health, including cholesterol and blood pressure, were very good,” said author Sumei Hu, currently at the Beijing Technology and Business University. “This suggests that low body fat may trump physical activity when it comes to downstream consequences.”
The researchers are now planning to expand their understanding of BMI by looking at differences between normal and healthy underweight people.
This study was published in the journal Cell Metabolism
