What happens when Christians don't change?
Like, if a Christian watches too much tv, or goes online too much, what happens if they don't change?
How do you define "too much"?
If the Lord tells me I am watching too much tv, that it is becoming a god/idol and consuming too much of my time, and if I tell him that I am serious about following him but refuse to hear what he is telling me; then, from experience, he will either keep confronting me with the issue til I listen and surrender to his Lordship, or he will find ways of keeping me so busy, happy and fulfilled that I no longer have time to watch it so much, and in time I will realise that I don't miss it and can do without it.
Ditto being online. Though in both cases, I may just need to be more discerning about the types of programmes I watch/sites I log on to.
What happens when a Christian eats too much food, especially unhealthy food, and they don't take care of themselves with proper diet and excercise, what happens?
Again, define "too much" food. What is more than enough for one person, may be only a small portion for another.
If I regularly take in more calories than I am burning off, I will put on weight. If my diet were to consist of a large amount of junk food, I may become unhealthy/fat/anaemic.
If that were to happen, my dosctor might well tell me that I was heading for trouble. If I refused to listen and developed weight-related health problems, I would suffer and would probably have only myself to blame if I did myself some long term damage.
What happens when a Christian simply reads the bible, but other than excepting the free gift of salvation, they rarely do what the bible says, what happens?
Well it depends what you mean by "do what the Bible says".
It seems from some of your former posts that you believe that all Christians should live simply/in faith and go to help the poor.
But that's not correct. What the Bible teaches is that God calls all believers to serve and follow him; that he gives us gifts to build upp the church and do the things he has called us to do. Ephesians says that we were created to do good works, which God prepared in advance for us to do. (Eph 2:10).
So what we all need to do is discover what gifts we have been given, for what purpose, and who and where we are to serve. Some Christians will have a ministry among the poor, others will have a ministry among the rich or middle class. Some will be called to work among the elderly, children, the mentally ill, others will be called to witness to managers in the city.
The Christian who has lots of money and is called to that group of people, should not feel guilty for not working in third world countries; those called to do the latter, should not be scornful or critical of those called to the former.
If I have been called to serve as a teacher/nurse/pastoral worker/plumber/scientist/librarian or whatever, and I KNOW that I have, but I decide to go off and witness to people in Germany or work among the poor in India - even though these are worhwhile vocations, I am still being disobedient to God.
If we are saved, declare Jesus as Lord but do nothing to show our faith - then others will not be able to see our faith in action, and may well question it.