Marcus Ericsson has thrown his weight behind the reasons why Sauber team mate Pascal Wehrlein is generally faster than he is.
The Swede says there is a 10kg weight difference between himself and the German, a natural ballast which he estimates is worth four tenths of a second per lap!
Wehrlein leads Ericsson 9 to 4 in the intra-team qualifying battle while the former has scored five points so far this season against zero top ten finishes for the latter.
"We've been close, but he has good numbers on me, which I don't really like," Ericsson said.
"It's also been difficult for me with the weight disadvantage.
"At the beginning of the year it was a bit less but for the last four or five races it's been 10 kilos difference.
"That is a lot of lap time on every lap on every track - usually they say it's three or four tenths a lap with 10 kilos."
Ericsson admits that keeping his weight under control is a never-ending battle and an inevitable by-product of his height.
"It makes it difficult. It's [Wehrlein’s pace] my benchmark and I need to beat him as much as I can.
"It's been a lot of years in F1 now where I've been in probably the worst car, and it's difficult then to show your skills, and that also makes it more difficult to get a better seat."
Ericsson's prospects don't look set to improve anytime soon. Indeed, he may even struggle to remain at Sauber despite his close relationship with the Swiss outfit's owners.
The team has renewed its engine supply agreement with Ferrari who may channel its young talent through Hinwil, to Ericsson's detriment.
Contact was recently initiated with Williams, but chances of his joining the Grove-based outfit are remote.
"Williams is looking less likely for me and Sauber is probably the strongest option at the moment,” Ericsson confirmed.
"There are always people trying to take your seat and there always will be.
"We've been looking around a bit at different seats, which I think everyone that doesn't have a contract for next year has to do.
"At the moment nothing is done. My management is working hard on it and we see there are some options."