The patron saint of parish priests, St. John Vianney, used to eat a moldy potato for a meal.
And St. Patrick (patron saint of Ireland) ate one slice of burned toast for his meal on many occasions.
Their voluntary penances were the reason they performed many miracles. But in
the case of the Cure d'Ars, he attributed all his miracles to St. Philomena. And
when someone received a miracle that wasn't what they expected, he told them
to "take it up with her."