Tempeh is a fermented soy product that is commonly used as a plant-based protein source. It is made by culturing soybeans, which results in a nutty and savory flavor. Tempeh has a firm texture and can be used in various dishes, such as stir-fries and sandwiches. It is also a good source of essential nutrients, making it a popular choice for vegan bodybuilding. Some people prefer tempeh over tofu because of its higher protein content and distinct flavor.