"Never trust a skinny chef” is a saying that has been used on aprons and for book and newspaper article titles. The implication is that a skinny chef doesn’t eat much of his or her own food, or that the food isn’t very filling. The saying has been used since at least 1976.


Zazzle.com
Never Trust a Skinny Chef apron by mrsrnj
Never Trust a Skinny Chef mug by mrsrnj
created by mrsrnj (6/1/2007 11:56 AM)

4 March 1976, Augusta (GA) Chronicle, “French cooking is taught by expert” by Louise Thrash, pg. E1, col. 1:
The French use lots of whipping cream, pure butter, cheese, wines and liqueurs in their cooking. But as Chef Carles pointed out, “You wouldn’t trust a skinny chef, would you?”

Google News Archive
17 January 1979, Deseret News, “If a skinny chef can’t be trusted, prison chef can” by Jack Monson, pg. 8H, col. 1:
UTAH STATE PRISON—Never trust a skinny chef.

Google News
3 June 1981, Deseret News (Salt Lake City, UT), pg. F1, col. 2:
Never trust a skinny chef—he’ll ham it up!
By Winnifred Jardine

OCLC WorldCat record
Never trust a skinny chef
Author: Les Kincaid; Creative Cuisine.
Publisher: Las Vegas, Nev. : Teed-Up, 1984
Edition/Format: Book : English

Google Books
August 1987, Texas Monthly, pg. 108:
WHO SAYS NEVER TRUST A SKINNY CHEF?
By Alison Cook

26 February 1989, Chicago (IL) Sun-Times, pg. 48:
“Never trust a skinny chef,” confided Louis Szathmary, dean of restaurateurs;...

24 July 1990, Deseret News (Salt Lake City, UT):
Hilton Hotels used to advertise ``never trust a skinny chef.’’

13 September 1992, Salt Lake Tribune (Salt Lake City, UT), pg. B3: 
“Would you trust a skinny chef who looks like he doesn’t enjoy his food?’’ Mr. Stucki asked.

AuburnPub.com
Hanging on until spring
By Chance Bear
Wednesday, January 20, 2010 12:00 AM EST
(...)
I mean, you don’t get my waistline by saying “no thank you” when it comes to desserts. I think it is my duty and my privilege to sample as much as possible. The old saying goes, and I quote, “Never trust a skinny chef.” Well, that may not be always true, but it is the excuse I give to my significant other.

Ohio.com
Glenmoor chef tightening belt with diet and fitness program
Meeker hopes to lose 200 pounds under new regimen
By Lisa Abraham
Beacon Journal food writer
Published on Sunday, Feb 07, 2010
‘’Never trust a skinny chef’’ is a common saying in culinary circles.

Although I like the idea, if you seen how hard alot of chefs work in a kitchen I wouldn’t be surprised if some of them ended up skinny! And what about restaurants for vegetarians?