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Caley Thistle need to beat Well to stand a chance of Premiership survival.
Victory, coupled with Hamilton Academical dropping points to Dundee, would see Inverness avoid finishing bottom, and automatic relegation, at the expense of a two-legged play-off.
"The players need to look after themselves the next couple of days," Foran said.
"We must go into details: what are you eating, what are you drinking? Don't get off your sofa, find babysitters for your kids - it's worth it, it's worth it. We need you to give your all now.
"It's a massive game, but it's one you go and enjoy, one you take to Motherwell, whereas the Hamilton dressing room before their game will be very, very nervous."
Inverness remain one point behind Accies at the foot of the table, heading into the final round of league fixtures.
Their outlook seemed bleak when they were thumped by rivals Ross County in the first of the post-split matches, leaving Caley Thistle five points adrift.
But wins over Accies, then Dundee on Wednesday night, have kept alive the Highlanders' hopes of retaining their Premiership status.
"It was a wonderful, wonderful performance (against Dundee) and we need it again on Saturday against a top team," Foran added.
"Motherwell have got two really good strikers, a strong midfield, defensively we'll have to be right at it once again.
"All the pressure that was on our shoulders goes straight to Hamilton. We can't influence what happens at Hamilton but I do know, I've been in football a long time, they'll be feeling a hell of a lot of pressure right now.
"There's no sugar-coating it, no hiding it, that pressure's lifted off our shoulders and goes straight onto the Hamilton players. It's a huge game for them, and we need the same passion, hunger, desire, as we had last night, and what will be will be."
Foran insists he has no interest in keeping tabs on Accies' progress at New Douglas Park, as his side do battle with the Steelmen in Inverness.
The former Caley Thistle stalwart, who made over 150 appearances for the club, has painful memories of their last top-flight exit, when a 1-0 defeat by Falkirk in 2009 sealed their relegation.
"I missed a few great chances, so that haunts me to this day," Foran said. "We gave 100% effort and that's all you ask from the players now, 100% effort and commitment for the jersey.
"The supporters were magnificent last night, I'm sure they'll be down in their droves again. We're going well, we're full of confidence and we can't wait for it now."
Inverness boss Richie Foran has urged his players to rest ahead of Saturday's seismic clash with Motherwell.