Hello and thank you for the question!
Body odor is the result of bacteria breaking down protein into certain acids. It usually becomes evident at the age of 15.There are different causes or situations that may cause a body odor:people who are
obese and especially those who regulary eat spicy foods,people with
diabetes,people with hyperhydrosis(a condition when people sweat too much).Also,we wear shoes and socks, which give the bacteria more sweat to break down into smelly substances. Moist feet also raise the risk of fungi developing, which can also give off unpleasant smells.Usually its not neccessary to see a doctor about this problem,because you can treat it by some self care techniques(deordorants or antiperspirant,wash daily,change clothes,avoid spicy foods,etc)But,if yoy realise that you start sweating at night,you have
cold sweat,you start sweating much more than you normally do,you have to consult a doctor!
Best regards!