This year, Feb. 16 is referred to as many things including Shrove Tuesday, Fat Tuesday for Mardi Gras or Fastnacht Day.
"Celebrated around the world in different ways. Here in eastern Pennsylvania, we eat donut," said Tom Thompson, owner of Mary Ann Donut Kitchen in Allentown.
Fastnacht Day happens the day before Ash Wednesday, which marks the beginning of Lent and fasting.
With one day to spare, people were pigging out while eating sweets and fat, things that many give up for Lent.
"I always try to stop by earlier because it's popular," said Sean Morrow of Allentown.
Customers loaded up on Fastnacht donuts at Mary Ann Donut Kitchen.
"Most Fastnacht are made with potato dough and then fried in lard and they're heavy. Ours are not," Thompson said.
They've been adding a twist to their ingredients for 60 years.
"It's made with citrus flavor. We use orange and lemon in the dough," Thompson said.
And customers love it.
"We got 52 dozen for about 500 plus employees at both of our sites at Thermo Fisher Scientific," said customer Katy Kizeik.
Mary Ann's will continue selling their donuts until the end of the month.
Over at Lochel's Bakery in Hatboro, they've been sticking to the basics since 1942.
"Traditional Fat Tuesday donut made with mash potatoes in the dough and they're available in eight varieties," said Lochel's Bakery owner Kathleen Lochel.
They've extended their Fastnacht sale one more day as customers buy it by the dozens.
"Today is Fat Tuesday and that's the day I get my donuts," said customer Patrice Felahe.