年輕人還是要正常體重，

但中老年還是福態一點好，但不能肥胖。

People who start adulthood with a body mass index (BMI) in the normal range and move later in life to being overweight - but never obese - tend to live the longest, a new study suggests. Adults in this category lived longer than even those whose BMI stayed in the normal range throughout their life.