Researchers believe that obesity is related to the parasitism of some microorganisms that can produce specific gases in the human body  These microorganisms make their exhaled gases smell worse  CS Medical Center in Los Angeles analyzed the exhalations of 792 physical examinees and found that the body height and body mass index (BM2) of people with high exhaled methane and hydrogen is 2
4 points higher than that of normal people, that means, they belong to the category of obese people
The mixture of methane and hydrogen smells bad.