Claudio Ranieri says Leicester are experiencing normality this season after their extraordinary Premier League title success.
The Foxes on Saturday lost 3-0 at Chelsea, their predecessors as champions.
"Last season we were not in this world, we were out of this world," Ranieri said.
"And now we come back into the world and we have to react.
"What happened last season is something... it's not possible, it's crazy.
"Now we are normal. We are the normal Leicester, who have to fight."
Ranieri accepts his team - without a point away from home this season - are not showing the characteristics which delivered such a shock title.
And he will demand positivity and a change in fortunes through hard work, not incentives.
Ranieri, who last year awarded his players pizza for a clean sheet, added: "The body language is not good. Last season, I didn't see this body language. We have to react. I want positive men.
"It is not the energy of the power, but the energy of the mentality.
"It's not pizza, it's not beer. You have to be used to play in the Champions League or (Europa) League and then you take your training sessions.
"When we play away we are not competitive, it's very strange. Last season we were so solid, so strong, so concentrated, very, very hungry and now we have to change our mind."
Leicester play Copenhagen in Champions League Group G on Tuesday in a match which could go a long way to securing a place in the knockout stages.
Europe's elite competition has been suggested as a reason for Leicester's domestic dip, but Ranieri is not concerned at the possibility of relegation.
Ranieri, who throughout last season focused first on the 40 points seen as the requirement to avoid relegation, said: "Worried? No, but we have to react.
"I said to my players the Premier League is so long and we have to achieve 40 points.
"The Champions League is two months, in or out, and for this reason it is important to be competitive in both matches, Champions League and Premier League."
Chelsea won the 2014-15 title under Jose Mourinho before a dramatic fall from grace last term.
Mourinho was sacked in December, with the Blues perilously close to the relegation zone. They finished 10th.
The self-proclaimed Special One will return to Stamford Bridge as boss of Manchester United on Sunday in a much-anticipated clash.
Antonio Conte, Mourinho's permanent successor, believes the Blues should welcome their former boss.
Conte said: "Jose Mourinho was here for many years and he won a lot with this club and I think it is right to have a great reception."