England head coach Eddie Jones has advised prop Mako Vunipola to lose weight ahead of this year's Autumn internationals, the 25-year-old has said.

Vunipola, who has 35 caps for England, was named in a 37-man training squad for the Autumn internationals and will continue his on-off battle with Joe Marler for the starting loosehead slot.

The final squad for the Autumn internationals to be announced on October 26.

"A couple of weeks ago I got a letter saying I was in contention. Everyone got (a) letter, reminding us what to work on. Mine said not to eat too much - to lose some weight," Vunipola told British media.

"I tried to look after what I ate and my diet during the summer. Eddie keeps you on your toes. I'm fighting for my place in this squad. Joe Marler's a world-class player so to have him back in the squad is a bonus."

England, unbeaten since Jones took charge after last year's World Cup, host South Africa, Fiji, Argentina and Australia in November and December.