[5] In 2007 researchers at Leeds University evaluated 700 variants of the sandwich, experimenting with different cooking styles, types of bacon, breads, oils, and special additions.

"[6] Another study by the Direct Line for Business listed the top additions to the traditional bacon butty in England.

[7][8] The BLT is a popular variant of the bacon sandwich with the additional ingredients of lettuce and tomato, but served cold.

[9] In Ontario, Canada, peameal bacon sandwiches are a common variation, usually served on a soft kaiser bun, and are considered the unofficial dish of Toronto.

The Double Down contains "bacon, two different kinds of melted cheese, the Colonel’s 'secret' sauce... pinched in between two pieces of Original Recipe chicken fillets.

[citation needed] Numerous studies have showed a connection between processed meats and an increased risk of serious health conditions such as type 2 diabetes, various cancers, and cardiovascular disease.