It is all due to bacteria that feed on sweat. Bacterias are attracted towards the sweat on your feet and starts feeding on them. These bacteria get rid of waste on your feet which are in the form of organic acids
Remedies To Get rid From Smelling Feet:

# To begin with what the doctors say about the treatment of chronic foot odor, you need to treat this problem more scientifically. They suggest the smelly feet victims to wash their feet on a daily basis using antibacterial soap. After washing, it is important to dry the feet completely.
# Drink a lot of water. It is a better way to fight body odor.
# Do not wear synthetic socks but a clear pair of socks, made with absorbent material, such as cotton.
# Spray your feet regularly with a usual antiperspirant and shower foot powder in your shoes.
# Do not wear the pair of shoes for two days consequently.
# The sneaker wearers should interchange between two pairs to make it dry out for a while.
# While indoors, wash your feet and prefer going barefoot. Wearing sandals is also a best alternative
# Paraffin treatment is another good idea to fight body odor. In this method, the professional waxes the bottom of one’s feet using the melted down cooled wax.
# Another treatment is to do without any intake of sugar and alcohol for about a week. This experiment on your body may tell you if these elements have to do anything with it.
# Buy and use some acne soap on your feet. It is a special soap that is anti bacteria and helps to fight with body toxics.