go on a diet （为了减肥）而规定饮食；节食

例句：
 

Mary went on a diet and lost four pounds.
玛丽因为节食瘦了四磅。

I'm gaining weight.I must go on a diet.
我的体重在增长，我必须要节食。

The doctor said I am a little overweight.So I should go on a diet.
医生说我有点超重，所以我需要节食。

 

背景音乐：
Glee Cast-Saving all my love for you