Quick English to Japanese Help
 

The increase of eating here is a problem.
something like that

What is the context?

it's just a sakubun about how eating too much fast food causes obesity. My sensei wants me to edit my sentence because it's a little unclear, so I need to say the increase of eating at Mcdonalds is a problem.

What's your sentence? Always "show your work" here to get good help.

ファストフードは日本の問題だと思う

That says "Fast food is Japan's problem." That's different than what you are trying to say.

My sensei said that my sentence is too vague. But I'm also mentioning the trend of eating at fast food places like McDonalds, so she doesn't want me to just say that fast food is bad.

So, where is your own attempt to say in Japanese what you need to say?

マクドナルドで食べることの増えたことは問題だと思う 。but it doesnt sound right somehow

You are getting closer. This means "I think the fact that more people are eating at McDonald's is a problem."

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).