It is not until you have lost your health____you know its value.

It is not until you have lost your health____you know its value.
It is not until you have lost your health____you know its value.

It is not until you have lost your health____you know its value.
before

before

that 强调句
直到失去了健康你才会明白健康的价值

that

that 这里的确是强调句
这是固定形式，即it's not until…that
与他相仿的形式有：Not until+状＋部分倒装。Eg:Not until he finished his homework did he go to bed.
还有：not…until。Eg:He didn't go to bed until he finished his homework.

that
是强调句

that