The phrase ‘never trust a skinny chef’ implies the chef does not enjoy their own food enough to fill up on it, and so may not be fully suited to their role in that respect.
It is a well-known expression, frequently seen emblazoned on aprons, tea towels, and mugs.
The saying is certainly nonsense. In fact, the top chef said that if a restaurant cook is overweight, it implies they've "eaten all the good bits."
Speaking in London last month at the reveal for 2019's Michelin-starred restaurants in the UK, the celebrity chef,Gordon Ramsay said he believes that in order to be consistently excellent, a chef must "stay fit."
"Chefs, as you know, don't have the world's best eating habits," Ramsay said. "Any chef will tell you that they're lying if they say they sit down and eat dinner before cooking dinner. So, you stay nimble. You don't eat before service and you taste everything."
"Trust a skinny chef because you know they haven't indulged and eaten everything. It's the customers that should be eating, you should be tasting, staying fit and in front of your brigade, to set an example."
