Like Leeds, Koch did not fully know what to expect from England's top flight, though he had experience of playing at the highest level of competition at Freiburg, the Bundesliga side who sold him to United for a reported fee of £13 million.
Life in the Premier League did not get off to an easy start for the German, who handled the ball in the fourth minute of his debut to gift Liverpool a penalty which Mohammed Salah converted, putting Leeds on the backfoot at the start of an extremely hectic 4-3 opening day defeat.
Premier League attackers such as Salah have proved especially challenging, Koch revealed, and have forced the centre-back to put weight on in order to keep up.
"In Germany I had the feeling that more emphasis is placed on ball possession," Koch said.
"Here, it's already the case that every team has strikers that are well built and very fast.
"Especially in the English league, I think it was important for me to put on some weight - if you maybe gain one or two kilos - and still not become slower."
As well as the players, Koch claims that the supporters in the stands behave significantly differently to those of his home nation, as Premier League fans are more responsive to what they observe on the pitch.
"I had to play here for almost a year without a spectator," Koch told SWR Sport. "Then I was glad to finally play at home in front of our fans.
"And I have to say, I really had goosebumps and it was very special.
"The difference to Germany in general, I would say, it is a bit more game-dependent.
"Certain actions get celebrated and the fans are very connected to the game."
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