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-ranker was told he was in contention for the England 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."