15 is said to be the number of pounds that many students gain in their first year of college; and freshman 15 is the often observed phenomenon of weight gain among first year college students.

据说，之所以会出现15这个数字是因为很多学生在大一这一年体重会增加15磅（约13斤）；而freshman 15则指代学生上大一时体重增加这个现象。

Health educators at American universities say that the Freshman 15 have been on the scene as long as they have. It seems fairly common.

美国各大学的健康教育学家们表示大一新生体重增加的现象由来已久，好像已经司空见惯了。