Replying to Innocent Until Proven Guilty

Although i am no expert on the system of law in Canada yet and have no knowledge of how things are done in the US or in Europe. With my high school law education i have come to a conclusion with my self that our legal system does not give the accused the right to be innocent until proven guilty.

I think this for one major reason. This reason is that when you are arrested, if the crime is deemed "serious enough" such as murder, treason, extortion, rape and numerous other crimes you are detained in jail (with less serious crimes you can be granted bail and set free if they feel its appropriate). Once you are detained and held against your will i believe that this is when you lose your rights as an innocent person.

Now if everyone is "innocent until proven guilty" doesn't that mean that you should be set free until you have a trial and are proven guilty of the crime? I'm just wondering if there is anyone else who has any thoughts on this subject? Also if someone could tell me if the American and European system is similar that would be awesome.