一查文獻,發現研究人員對這兩種情況還真有一些探討。老宋的朋友的情況很可能是“代謝肥胖而體重正常”(Metabolically obese normal weight);小龐的情況可能是“代謝正常卻身體肥胖”(Metabolically healthy obese)。關於這方麵的研究有一篇綜述寫得很好,我先摘要介紹一下 (14)。
韋伯氏字典關於肥胖的定義是身體裏脂肪的過多積累和貯存。但臨床關於肥胖與否的測量最初是量一定身高下的體重,後來發展成體重指數(BMI:Body Mass Index,體重/身高的平方,單位是公斤/平方米,大於25為超重,大於30為肥胖)。肥胖當然更應該用脂肪的含量來定義,比如脂肪含量超過體重的25%(男)或35%(女)為肥胖。但由於測BMI遠遠比測脂肪含量容易,所以BMI被廣泛運用。有人對BMI正常的人的脂肪含量進行了測量,在男性中數據從5.6%到31.2%,在女性中從4.6%到51.1% (8)。所以用BMI來衡量肥胖是很不精確的。這很容易忽略了這樣一些人:他們體重正常甚至偏瘦,BMI小於25,但脂肪含量卻很高。這些人往往更容易得糖尿病與心血管疾病。
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感謝閱讀留言,我有一位朋友也是騎車健身的,俺是非常佩服!