你的句子，每个单词的首字母为何都用了大写？是文章标题吗？若不是，建议改为：

This is exactly how many hours of sleep you need to burn fat fast.

这个句子的表语部分，实际就是how 引导的一个名词性从句，也叫表语从句。

英语中，几乎所有的wh-word 都可以引导表语从句，例如：what, when, where, how, why 等。表语部分其实就是一个简单句，不复杂。结构就是：

This/That + is + wh-word ...

That is what is polluting the lake.

那就是污染湖水的东西。

That is when I realized the importance of journalism.

就是在那时我深深感到了新闻工作的重要性。

This is where the problem lies.

这就是问题的所在。

That is why he likes the place so much.

那便是他如此喜欢这个地方的原因。

The point is whether my parents agree with me.

关键是我父母是否同意我的看法。

The doubt is who has got away with the document.

疑点是谁拿走了文件。

That was where we camped last time.

那就是上次我们野营的地方。

The question is how we can do the work better.

问题是我们如何才能将这项工作做得更好。