In Texas, condemned inmates are executed by lethal injection unless the inmate wishes to be executed in a quick way. Some states in the south still use the electric chair while other states have found the electric chair to be "cruel and unusual" and thus phased them out. California uses the gas chamber through the use of hydrogen cyanide gas, but the use of the gas chamber has been questioned.
The point of the post is, of all the ways inmates have been executed, I haven't heard of an inmate violently vomiting while being executed because of what they ate.
Also, yeah the state doesn't really like it when the condemned inmates jump the gun and try to kill themselves before the state can kill them.