I have eagerly consumed many accounts of early mountaineering expeditions in which the mountaineers always eagerly consumed Kendal Mint Cake (KMC). I got the impression that they would have found it unthinkable to set off without it.
Note that it is difficult to digest anything at very high altitudes, because digestion involves oxidation. Sugar, a simple carb, is the easiest thing to digest, and that is about all KMC is.
Sir Edmund Hillary and his team carried Romney's Kendal Mint Cake with them on the first successful ascent of Mount Everest in 1953. The packaging currently includes the following: “'We sat on the snow and looked at the country far below us … we nibbled Kendal Mint Cake.'[this quote needs a citation]
A member of the successful Everest expedition wrote – 'It was easily the most popular item on our high altitude ration – our only criticism was that we did not have enough of it.'”
Mint cake was provided for the Imperial Trans-Antarctic Expedition of 1914–1917, which was led by Sir Ernest Shackleton.
Ewan McGregor and Charley Boorman included mint cake in their supplies for their 2004 motorcycle trip around the world in Long Way Round.
The Kendal Mint Cake is also a standard part of the 24-hour ration pack issued to the Irish Defence Forces.
The basic ingredients (sugar and peppermint flavoring) -- and the picture in the link above -- seem very similar to the York Peppermint Pattie, which
was first produced in York, Pennsylvania, by Henry Kessler at his York Cone Company in 1940, for sale in the Northeastern United States, Ohio, Indiana, Illinois, and Florida.
The preeminence of Mint Cake in extreme expeditions may simply be because it got a much earlier start than the Peppermint Pattie, but were there other factors in play also? Is there any evidence that PP even tried to compete in that niche?
(I have no connection to the producers of either.)