BMJ本期聖誕節專期的這篇文章很有趣。
http://www.bmj.com/content/349/bmj.g7257
減肥後那些脂肪都去哪裏了？調查顯示很多醫生，營養師，健身教練都錯誤地認為脂肪被燃燒成熱量/能量排出去了。這篇文章幫我們複習了一遍基本生化知識，結論是：脂肪通過最終產物CO2從肺部排出體外了。可以說減肥者就是個碳排者。
Fig 1 Responses of a sample of doctors, dieticians, and personal trainers to the question
“When somebody loses weight, where does it go?” (Correct answer CO2)
Fig 2 When somebody loses 10 kg of fat (triglyceride), 8.4 kg is exhaled as CO2. The remainder of the 28 kg
total of CO2 produced is contributed by inhaled oxygen. Lungs are therefore the primary
excretory organ for weight loss. (This calculation ignores fat that may be excreted as ketone bodies
under particular (patho)physiological conditions or minor amounts of lean body mass,
the nitrogen in which may be excreted as urea)
......
Our calculations show that the lungs are the primary excretory organ for fat. Losing weight requires unlocking the carbon stored in fat cells, thus reinforcing that often heard refrain of “eat less, move more.” We recommend these concepts be included in secondary school science curriculums and university biochemistry courses to correct widespread misconceptions about weight loss.
Where does the fat go?
