in fact I have been eating basically nothing but rice protein. as diet `s was my base of a protein. and some other fruits and vegetables. but the last two days I ate only protein and some melons + nuts.

Bad breath is usually caused by indigestion. That is, a bad combination of food you put in your gut. Or something to eat that does not digest very well in itself, such as highly processed foods. Sugar also will, as it can and often do, produce the proper fermentation in the intestine (the bad kind of fermentation). If you eat your fruits and vegetables and rice, which definitely would cause indigestion. As a general rule, the fruit is to eat alone, with nothing else. I do not know what is protein rice, but why not eat rice? protein instead of rice.