It is not a recognized legal defense in jurisprudence, but a catch-all term coined by reporters during their coverage of the trial of defendant Dan White for the murders of San Francisco city Supervisor Harvey Milk and Mayor George Moscone.
As an incidental note, Blinder mentioned theories that elements of diet could worsen existing mood swings.
[1] Another psychiatrist, George Solomon, testified that White had "exploded" and was "sort of on automatic pilot" at the time of the killings.
Twinkies were only mentioned incidentally in the courtroom during the White trial, and junk food was a minor aspect of the defense presentation.
[4] The day after the verdict, columnist Herb Caen wrote in the San Francisco Chronicle about the police support for White, himself a former policeman, and their "dislike of homosexuals" and mentioned "the Twinkie insanity defense" in passing.
As a result of negative publicity from the White case and others, the term diminished capacity was abolished in 1982 by Proposition 8 and the California legislature and was replaced by the term diminished actuality, referring not to the capacity to have a specific intent, but to whether the defendant actually had the required intent to commit the crime.