Body odor (also known as fetid sweat or body smell) is the smell of bacteria growing from sweat on the body.  In some cases, causes of foul smell are heredity and obesity.  You should decrease your weight first to see if the body odor is better or not.  If not, perhaps it is caused from the heredity so you have to frequently try to stay clean.  Do not let you get too sweaty.  Just use perfume to easily eliminate the body odor.