Everyone has some kind of body odor, but it may be caused by different things at different times. Regular body odor is caused by not cleaning sweat from the skin, especially on areas like the armpits, and letting bacteria grow in the sweat. Body odor is also affected by things like the health of a person's liver and kidneys—if these organs aren't operating to purify toxins from the body, then those toxins get released through the sweat, skin, and breath. Body odor often develops while a person is asleep, as the body purges toxins from the system.
A sour smell is associated with processes such as fermentation, and with dairy products. When food reaches the stomach, it's broken down in a souring process with acid. As this breakdown occurs, a sour smell is released, often through belching, and the food moves into the intestines where souring continues. This causes the buildup of toxins in a person's body, and these toxins must be eliminated. If the kidneys and liver aren't able to do the job, the toxins, along with their sour odor, may be released through breath, skin and sweat.
A sour body odor occurs especially when certain foods like dairy are left too long in the stomach. To avoid this, be mindful of overeating, eating raw foods, consuming cold drinks before a meal, eating mostly fat, protein and starch, weak digestion, eating late meals and excess weight.