美國疾病控制與預防中心（CDC）最近發布一份報告稱，現在將近四成美國成年人屬于肥胖一族。而哈佛大學的研究預計，57%的美國兒童到35歲都會變成肥胖者。

測算肥胖的指標是身體質量指數（BMI），達到30或以上就屬于肥胖。BMI的算法是體重（公斤）除以身高（米）平方得到的結果。

BMI是衡量一個人體重偏低、正常、超重或肥胖最常用的標準。不過，BMI較為簡單也引起一些爭議。因為該指標沒有考慮脂肪和肌肉的差別（同體積的肌肉比脂肪重），也沒有考慮不同種族標準體重不同。

哈佛大學新研究使用的數據基于之前五項研究，具體內容是當前美國兒童和成人體重和身高數據。為了預測研究對象的體重在35歲以前如何變化，該研究會對成長趨勢進行模擬。

結果顯示，目前19歲以下的美國青少年里57.3%將在35以前變肥胖，其中約半數童年時期就會（或已經）肥胖，另外約半數將在成人后肥胖。

對目前BMI就超過35的嚴重肥胖孩子們來說，年齡越大他們在35歲以前擺脫肥胖的幾率就越低。比如目前兩歲的嚴重肥胖孩子，35歲以前改變肥胖狀況的幾率還有21%，而19歲嚴重肥胖的少年幾率就降至6.1%。

哈佛研究之所以用35歲當分界線，是因為人到35歲就可能開始出現糖尿病和心臟病等肥胖導致的并發癥。

“基于模擬模型，童年肥胖和超重仍將是美國一大健康問題，”研究人員寫道，“小時候肥胖預示了成年后很可能也會肥胖，如果小時候就嚴重肥胖，可能性就更大。”（財富中文網）

譯者：Pessy

審稿：夏林

While a recent report from the Centers for Disease Control and Prevention (CDC)suggested that almost 40% of American adults are currently obese, the new research predicts that over 57% of today’s children will be obese by the time they reach the age of 35.

Obesity is classified as having a body mass index (BMI) of 30 or higher. BMI is calculated by dividing the subject’s weight in kilograms by the square of their height in meters.

BMI is the most widely used system for establishing whether someone is underweight, of normal weight, overweight or obese. However, it’s rather simplistic and is controversial as a health indicator, as it doesn’t take into account the differences between fat and muscle (which is heavier than fat), nor does it factor in ethnic background.

The new research took data from five earlier studies about actual American children and adults’ height and weight, and simulated growth trajectories in order to project where today’s kids were likely to end up by the age of 35.

The results showed that 57.3% of today’s kids, up to the age of 19, will be obese by the age of 35. Of those, around half will become (or already be) obese during childhood, and half will become obese later on.

For those children who are already severely obese—that is, with a BMI of 35 or more—the chances that they will cease to be obese by their 35th birthday drop with age. At the age of two, the likelihood of that happening is 21%; by 19, the likelihood drops to 6.1%.

The age of 35 was picked for the study because that’s when obesity-related conditions such as diabetes and heart disease often start to kick in.

“On the basis of our simulation models, childhood obesity and overweight will continue to be a major health problem in the United States,” the researchers wrote. “Early development of obesity predicted obesity in adulthood, especially for children who were severely obese.”