In which tradition did Buddha say this?
That would be the Buddha Himself, see the story of the life of the Buddha. Even children know this.
However asceticism is part of the practice, eg. Eating one meal a day is asceticism.
That is not asceticism in the way that the Buddha was referring to it as, or the kind he was cautioning against as being not part of a Middle Path.
The Buddha was against practices that pushed the body to the point of being potentially lethal, or making oneself ill or injured, or damaging the body. Such as the types that He Himself had practiced, and the types that the Tendai sect are now practicing.
He said they were unnecessary and unhelpful. He likened it to a string on a musical instrument being tightened to the point of snapping (see heart attacks from the Tendai practice)
Having one meal a day is fine if you are doing a more gentle practice.
Having one meal a day when you are traveling potentially more than twice the distance of an olympic marathon, with only 2 hours of sleep a night is suicidal.
The Buddha would not have endorsed a practice that caused people to have heart attacks from sheer exhaustion and malnourishment in ratio to the energy and calories expended.
Bodhidharma sat meditating facing a wall for 9 years...
I sincerely doubt that Bodhidharma spent nine years facing the wall without adequate food to keep him alive.
Sitting still in meditation requires very little calories. And unless he had an assistant to bathe him, and feed him, and prepare his food, and change his chamber pot, he got up sometimes to go to the bathroom, and cook, and eat. He also likely slept at least some. There's a limit to how far one can sleep deprive oneself before one's body just sleeps with one's eyes open. (in fact, according to one story,[if it's accurate] we know
he fell asleep, because apparently he got so frustrated [anger, acting on anger] with himself,[probably not realizing that there was indeed a physical limit to sleep deprivation] that he cut his own eyelids off [not a smart thing to do, nor would it stop his body from going to sleep], it wasn't until later he realized a middle path. But he likely beat himself up quite a bit before finding it) Not to mention that sitting in a cave, is not exactly extraordinarily dangerous.
"Life is full of suffering. AND Life is full of the Eternal
IT IS OUR CHOICE
We can stand in our shadow, and wallow in the darkness,
We can turn around.
It is OUR choice." -Rev. Basil Singer
" ...out of fear, even the good harm one another. " -Rev. Dazui MacPhillamy