James Haskell's return to England's training camp will give him a chance to keep an eye on any "junk-food athletes" within Eddie Jones' squad.
Despite being banned for his country's opening two Six Nations games, against Italy and Wales, Haskell was added to the 36-man squad Monday, alongside suspended prop Joe Marler.
The Wasps back row, who released a health and fitness book "Perfect Fit" earlier this month, revealed that the group's nutritional needs were carefully looked after while they were in camp.
"At Pennyhill Park [England's Surrey training base] everything they want you to eat is laid on," he told ESPN. "So they're quite strict on that type of stuff, which is great."
Haskell is well aware of the benefits a controlled diet can have on a player's career but not all of his teammates in the professional game quite share his discipline when it comes to rationing fast food.
"There are a lot of athletes who have great bodies, who are young, who have the ability to put whatever they want in their body -- junk-food athletes I call them," Haskell said. "At some point they are going to go over the edge."
And while England's chef has devised a menu to ensure that players are in peak condition come matchday, not every member of the squad can resist the urge for more sugary products.
"There's never any real issues [with England], and if there is, lads have got their cars and a few of them disappear," Haskell added. "I remember there was one player who every night you'd see him coming back from Marks & Spencer with a couple of bags of contraband.
"Another player who I've roomed many times with lives off Horlicks, Hobnobs, Ribenna and club sandwiches from the hotel."
He added: "If it works for them, it works for them. I just wonder how good they could be."
Having played for clubs in France, Japan and New Zealand, as well as England, over during the past decade, Haskell has hit on a winning formula when it comes to his own pre-match food intake.
And the British & Irish Lions tourist says the key lies with keeping things familiar -- and clean.
"At the moment, I would always wake up and have eggs in some form, maybe four or five of them, I would have a couple of pieces of toast, I would have porridge, maybe with some protein powder in it, a cup of coffee, two litres of water with rehydration stuff in," he said.
"A couple of hours after that I will have a piece of salmon, brown rice, some broccoli, again probably another litre and a half of water and then I'll go to the game.
"If you've got an evening kick off, you'd throw another meal in there as well."