England boss Eddie Jones sent prop Mako Vunipola a letter saying he should shed some weight before the next season.
The New Zealand born front-row was told he was in contention for the England number one jersey but that he needed to watch his diet over the European Summer break.
"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 Eurosport.
"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."