Soy and Soy-Containing Products
Soy contains several chemicals that are structurally similar to estrogen, which decreases libido. It's also possible that the estrogen-like compounds found in soy may also down-regulate sexual activity in the brain. However, the effects of soy tend to be bigger issues for vegans and vegetarians who consume large quantities of soy products like tofu or edamame as sources of protein or meat substitutes. But even if you're not a vegan or training to be the next Arnold Schwarzenegger, Cozzolino says it's still virtually impossible to avoid soy completely, since soy-based products are commonly used in many food-grade seasonings and emulsifiers.