|This is a concise and simply written argument for changing the habits of those who are eating fast food. The ideas are communicated effectively and with ease. You make strong points and point to an article or letter scribed by someone else. I'm not sure exactly what the article might say originally and I won't bother looking it up, but it's clear that your stance is that fast food is a negative outlet in some people's lives.
Unfortunately, I don't think anything new is really said here, at least that I haven't heard before.
I also thought this little bit could be revised or altogether taken out:
"Often, if we eat too fast, stomach ache is inevitable. This is one of the bad impacts. The other one is that the time for gathering with families and friends will be lessened."
Also, I do agree that packing your own lunch as opposed to eating fast food is probably the best option. I think everyone already knows this. Sometimes the convenience of eating fast food outweighs the benefits of not in the minds of many. I personally eat very healthfully but I still eat some fast food from time to time. It's kind of unavoidable for many without really making some significant changes. So to say that eating less fast food is preferred may be better. You don't outright say not to eat fast food at all, although you're clearly against it. It might be helpful to suggest how much or to quantify it somehow. If you are suggesting that more people should stop eating it altogether that is something else entirely and I would come right out and say it. Also, if I've ever sat down at a fast food restaurant I've hardly felt like I was being rushed out by the desire of others to take a seat. Usually there are plenty of open seats and where there aren't, drivethroughs have already been invented...