Kevin Magnussen has said he will gain weight in order to cope with the physical demands of the 2017 Formula One cars.
Compatriot and former F1 test driver Tom Kristensen said that Magnussen should lose weight in order to compete with taller new team mate Romain Grosjean.
"I have talked to him (Kristensen) about it, and I do not agree," he told the Danish broadcaster TV2. "We will need some more weight to run these new cars at the limit. At least I hope so, because we are told that they will be up to six seconds faster than the old cars, and I think that's going to make them really hard to drive."
"So I have to put some weight on, but not much. I'm quite light already, so I think I'm doing the right thing," he added.
Thomas Jorgensen, Magnussen's trainer, also confirmed the plan.
"Kevin is lighter than Grosjean, and Kevin will probably need three kilos to be where he needs to be physically to take the forces of these wider tyres and more downforce," he said.
"So I would say the opposite of Tom. Kevin needs to put on a little, but of course it's muscle mass, not fat. We'll achieve it by the end of February," he added.
Bahrain International Circuit - Winter testing