Our skin is the largest organ of our bodies. It is made up of living tissue that is designed to protect the other organs and cells within the body. Through pores, or tiny holes in our skin, sebum is excreted. Sebum is an oily substance that is made in the sebaceous glands; it helps keep moisture in our skin and microbes out. Under the oily sebum you'll find 15 to 20 layers of dead cells that are shed and replaced continually. The layer of dead cells in known as stratum corneum. Under that you'll find the stratum lucidum, which is only on the palms of our hands and soles of our feet. You can remember the term "lucid" or clear layer - which is our thick skin. Next are the stratum granulosum and stratum spinosum, where our skin cells are flattened and pushed opward. And finally is the stratum basale (or base/bottom) this is where the skin cells and the melanocytes (cells which make skin color) are produced. The stratum corneum, lucidum, granulosum, spinosum and basale all make up what is known as the epidermis. Our skin is made up of multiple layers. The deepest layer is called the subcutis; it houses fat that acts as a buffer against bumps and bruising. Between the outer layers - collectively called the epidermis, and the deep subcutis layer, is the dermis, which contains blood vessels and glands. Besides the sebaceous glands, our skin also has 2 types of sweat glands - eccrine and apocrine glands. Apocrine glands are found in the armpits and a few other places on our bodies (like the groin, chest, and eyelids) while eccrine glands are found everywhere else. Our bodies produce sweat everywhere. For the most part we don't notice it because it's mainly made up of potassium and helps to regulate our body temperature. But when we are really hot, the sweat will contain sodium (or salt) and chloride. The sweat from our armpits will also have fatty acids and protein. It's usually thicker and yellowish, and when it mixes with bacteria on the outer layer of our skin, it produces an odor. The fluid that makes up our sweat comes from the liquid between our blood cells in the dermis (or the middle layer of skin). When our bodies break down protein one of the by-products or waste produced is ammonia. Most ammonia is converted to urea and leaves our body in urine. Some ammonia, however does not get excreted in our urine and it, along with excess urea leaves our body via sweat. How would consuming less protein affect the composition of your sweat?
For an interesting read, check out http://health.howstuffworks.com/skin-care/information/anatomy/do-vegetarians-have-smellier-sweat-than-omnivores.htm