Can a complete sentence have a full stop in the middle, and can it be a long sentence?

Question

for example, "vitamin drinks are good for you, but in order for you to live a healthy lifestyle you should eat healthily and do plenty exercise" and can a complete sentence have more than 1 comma?

Answer 1

In the U.K., or U.S.A.?

(and yes, lot's of commas, in fact, I suppose, as many as you like.)

Answer 2

Yes, a complete sentence can have more than one comma, but it cannot have a full stop in the middle.  If it does, then it would be 2 sentences.  

Here's a re-write:  Vitamin drinks are good for you, but  to live a healthy lifestyle, you should eat healthfully and  exercise a lot.  

Answer 3

No, it can't have a full stop in the middle. You'll just have two sentences. You can have long sentences but be careful: it might become a run-on sentence instead. However, a sentence can have more than one comma.

Answer 4

What do you mean by "full stop"?  A sentence can have an unlimited number of commas in it.  In fact, one writer whose name escapes me, wrote a perfectly good sentence that ran an entire paragraph.  It takes skill to do that.