Black beans are flat and sweet. It has the effects of regulating middle-lower qi, nourishing yin and tonifying kidney, enriching blood, improving eyesight, promoting diuresis, reducing swelling, promoting blood circulation and caring skin. Black beans enter the kidney meridian, which has the functions of nourishing kidney and tonifying kidney, enriching blood and improving eyesight.

Soybean is sweet in taste and flat in nature, and belongs to spleen, stomach and large intestine meridians. It contains about 40% protein, which is comparable to animal protein in quantity and quality, so soybean has the reputation of "vegetable meat" and "green cow".

Eating together won't make any difference. It's better for your health.