Researchers believe that obesity is related to the parasites of certain microbes that can produce specific gases in the human body  These microbes make the smell of their exhaled breath more unpleasant  The CS Medical Center in Los Angeles, California analyzed the breaths of 792 medical examiners and found that people who exhaled a high amount of methane and hydrogen had a body mass index (BMI) 2
4 points higher than normal people, and they belonged to obese people
Obese people may host certain microbes that produce specific gases.