I want something stronger to "prove" that Rom 14 is talking about food offered to idols, as opposed to food in general.

Sunday's is about The Weak Brother.

http://www.ssnet.org/qrtrly/eng/10c/less13.html#sun

What is the practical definition of a weak brother?

I don't think anybody answered my question, therefore, I am asking it again.
What is the practical definition of a weak brother?

It would include people who refuse to be vegetarian when their circumstances make it perfectly possible.

But is food offered to an idol unclean? The common teaching of the Jews in that day was a resounding 'yes'! According to the Encyclopedia Judaica under the heading "Purity" it says:

"In the case of idolatrous offerings the law is even stricter [than the impurity of the idol itself] and Judah b. Bava says that it conveys impurity by overshadowing, as does a corpse"

Roma 14:21 [It] [is] good neither to eat meat nor drink wine nor [do] [anything] by which your brother stumbles or is offended or is made weak.

Now here is a very important verse. This is where Paul actually clarifies that he is talking about meat offered to idols. It is hidden from our eyes by translation but it is nonetheless there! Let's look at the Greek word that is translated "meat" here...

BDB/Thayers # 2907 2907 kreas {kreh'-as} perhaps a primary word;; n n AV - flesh 2; 2 1) (the) flesh (of a sacrificed animal)

In fact it is this same word that is used in

1Cor 8:13 (NKJV) Therefore, if food makes my brother stumble, I will never again eat meat, lest I make my brother stumble.

This is the only 2 places in the New Testament that it is used. In both cases the context was concerning meat offered to idols! Notice that even though it was obvious from reading the first and second verses of this chapter that he was talking about meat, this is the first time that the food that is spoken of here in Romans is classified as 'meat'. So this certainly clarifies things.

The third thing to say about the weak brother’s abstinence from meat and wine is that it is not because he believes this behavior is the way he gets justified or the way he secures his acceptance with God. This weak brother is not like the Judaizers in Galatia who thought that circumcision was essential to securing acceptance with God (Galatians 5:1-3). We know this because Paul was furious with this false gospel in Galatians (Galatians 1:6-9), but he gives no criticism of these weak brothers like that. They are not legalists. They do not think their abstinence earns God’s acceptance or contributes to their justification.