When the 1993 Act was passed, prisons were deliberately held to the higher standard to which other state institutions must adhere. They can certainly argue that free exercise of a religion would compromise their security or penal goals, but they have to come up with a sound and compelling reason for their argument. I haven't heard a single argument made by a prison to justify denying a vegetarian diet that makes any sense to me. Now, of course, I am a vegan, and someone who chooses not to eat meat because to me a vegan diet is a step in advancing a broad concept of justice and non-violence. But you don't have to hold such beliefs to see that respecting these requests for vegetarian food is not only required by the constitution, but makes complete sense in terms of penal and fiscal policy.
Vegetarian food costs less.
It is harder to quantify the savings in terms of the medical care required by prisoners, but after many have lived much of their lives in poverty, with poor diet and exposure to disease, drugs and alcohol, diet can assist in alleviating many common medical problems. Even more difficult to quantify is the benefit that each of the men who I am representing, points to as the most important benefit to themselves and to the society to which they hope to return. They describe their belief that meat makes them less able to control their own violent tendencies. It is my opinion, that prison authorities feel that they have lost control over inmates who subscribe to spiritual beliefs such as non-violence. He taught meditation and yoga.