Chelsea manager Antonio Conte has forbidden ketchup, brown sauce and fizzy drinks as he changes the nutritional regime of the first-team squad, club sources have told ESPN FC.
Conte has made improving his players' fitness a top priority as he aims to revive Chelsea's fortunes after last season's struggles.
The Italian implemented a programme of double training sessions with a heavy tactical focus immediately after his arrival following Euro 2016.
And he has adopted a similarly uncompromising approach to diet, instructing that all food items that do not have any nutritional benefit for elite footballers are removed from the canteen at the Cobham training ground.
A long-standing first-team tradition of pizza after matches is also expected to be abandoned.
Such measures are consistent with Conte's approach throughout his managerial career.
At Bari, he enlisted the services of Tiberio Ancona, a former footballer and personal trainer who later followed him to Juventus and Italy.
And at Euro 2016, his Italy players were forbidden to eat bread, pizza, crisps and ice cream.
The public signs during a low-key preseason are that Chelsea's players are responding Conte's methods.
Speaking at a Stamford Bridge open day on which 5,000 fans watched the team train, Ruben Loftus-Cheek told Chelsea TV: "The whole squad have been working really hard.
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"We look good and we look sharp, we're working tactically on our shape and we're really excited.
"The manager has been great. It doesn't matter whether you've come over from the academy or if you're a top player like John Terry, he's always trying to make you better."