but then didn't I say the increased part? I said "fueta-koto" so isn't that the increase part?

You seem to know more Japanese than you want to believe.

Why single out McDonald's, though?

「マクドナルドなどのファーストフード店で食事をする 機会（きかい）が増えたことは問題だと思う。」

or

「マクドナルドなどで食事をする機会（きかい）が増え たことは問題だと思う。」

機会＝ chances

We don't use 食べる the way you used it.

EDIT: Sorry, I didn't see MMM was trying to have OP rewrite.

I agree, they know more Japanese than they think they do.

McDonald's because that's the only one I really think of when I think of fast food places in Japan. It was the only one I've seen.
I don't put trust in my grammar. :P

So I think I'll go with
マクドナルドなどのファーストフード店で食事すること の増えたことは問題だと思う。
I leave out the chance part just to be more direct about it.
Thanks for the help :)

*sighs* We never say ことの増えたこと. Sounds too funny.

If you take a word out of a grammatically perfect sentence, you will almost always have to make other alterations (and do so correctly).