The system must be nourished. Yet we do not hesitate to say that flesh meat is not necessary for health or strength. If used it is because a depraved appetite craves it. Its use excites the animal propensities to increased activity and strengthens the animal passions. When the animal propensities are increased, the intellectual and moral powers are decreased. -- Ellen White, Testimonies Vol II, p 63.

What are these animal passions?

Sexual excess will effectually destroy a love for devotional exercises, will take from the brain the substance needed to nourish the system, and will most effectively exhaust the vitality. No woman should aid her husband in this work of self-destruction. She will not do it if she is enlightened and has true love for him. The more the animal passions are indulged, the stronger do they become, and the more violent will be their clamors for indulgence. -- Ellen White, Marital Duties and Privileges, pp 124-125.

The meat industry's marketers should love this one. If this is the truth, who needs Viagra?