This is how the chapter starts off:
Accept the one whose faith is weak, without quarreling over disputable matters. 2 One person’s faith allows them to eat anything, but another, whose faith is weak, eats only vegetables. 3 The one who eats everything must not treat with contempt the one who does not, and the one who does not eat everything must not judge the one who does, for God has accepted them.
So Frankie is exactly right in pointing at the historical and situational context of the letter.
Essentially the message Paul spells out is this:
a) Paul does not think that the Jewish dietary laws apply anymore. he does not believe food is a genuine religious concern. By logical extension Muslim dietary laws are equally irrelevant.
b) However, he recognizes that this is a tricky step to take for Jewish people. The same applies to modern converts from Islam... eating pork sausages would be most likely something they would not easily be willing to do, even post-Islam. It surprises many Muslims to hear that you can be a Christian without eating pork, or even meat, and many do. Some even are amazed to find that not all Christians regularly eat dog...
Paul suggests that the food or drink people consume should not be a matter for criticism or debate. Nobody should feel superior over another because of the diet they keep. He suggests simply not to discuss that issue as it can generate strife over a trivial issue. Instead simply do as you think is best. As a former Jew he knows exactly how dietary laws divide people one from another. He makes no secret of his view that clinging to dietary rules to him shows a certain lack in faith; but he also says we should not worry about that, after all none of us are without fault.
He also expresses the view that in food, excesses should be avoided. An excess in red meat and alcohol does in fact cause problems, as you can see at the mortality patterns in the "developed" world. So, it is prudent to opt for balance in diet. However, Paul firmly places these kinds of issues into the sphere of personal decision and responsibility.
