Fermentation is the breakdown of sugars, typically by bacteria and yeast. It’s an ancient technique used in preserving food. It’s used in the production of wine, yogurt and cheese.
Your gut has a variety of beneficial bacteria that help in the breakdown of food substances. Fermented foods are rich in these kinds of useful bacteria (or probiotics). Studies  have shown that the probiotics present in fermented foods can help improve digestion and overall gut health. They can also boost immunity in the body and help in losing weight.
This article discusses some of the best fermented foods for better digestion and health.
Tempeh is made from naturally fermented soybeans that have been compressed into cakes.
It’s a rich source of plant proteins that can be baked, steamed or fried and added to dishes. While this food is good for everyone, vegetarians might enjoy using tempeh cakes as a substitute for meat and other animal proteins.
Tempeh is rich in probiotics and many other nutrients important for muscle growth and repair. It may also reduce inflammation, improve bone strength and lower cholesterol levels.
Soy proteins like tempeh can help reduce the risk of heart disease. A review of over 40 studies  on the effects of consuming soy protein supported this claim. Eating about 25 g of soy protein daily for 6 weeks resulted in a 3.2 percent reduction in bad cholesterol and a 2.8 percent decrease in total levels of cholesterol.
Another study  suggests that tempeh contains some antioxidants. Antioxidants help reduce oxidative stress caused by free radicals.