If you've ever had issues with stomach pain when eating dried beans, or lentils, then soaking them before you cook may prove very helpful. Dried beans and lentils including split peas contain complex sugars that our human body finds hard to digest. The gas produced when absorbing them can cause bloating and flatulence. Soaking helps release some of these sugars into the water, which is why soaking, re-washing, and draining do help very much.